Utility of the INECO Frontal Screening and the Frontal Assessment Battery in detecting executive dysfunction in early-onset cognitive impairment and dementia

OBJECTIVE

The INECO Frontal Screening (IFS) and the Frontal Assessment Battery (FAB) are executive dysfunction (ED) screening tools that can distinguish patients with neurodegenerative disorders from healthy controls and, to some extent, between dementia subtypes. This paper aims to examine the suitability of these tests in assessing early-onset cognitive impairment and dementia patients.

METHOD

In a memory clinic patient cohort (age mean = 57.4 years) with symptom onset at ≤65 years, we analyzed the IFS and the FAB results of four groups: early-onset dementia (EOD, n = 49), mild cognitive impairment due to neurological causes (MCI-n, n = 34), MCI due to other causes such as depression (MCI-o, n = 99) and subjective cognitive decline (SCD, n = 14). Data were gathered at baseline and at 6 and 12 months. We also studied the tests' accuracy in distinguishing EOD from SCD patients and ED patients from those with intact executive functioning. Correlations with neuropsychological measures were also studied.

RESULTS

The EOD group had significantly (p < .05) lower IFS and FAB total scores than the MCI-o and SCD groups. Compared with the FAB, the IFS showed more statistically significant (p < .05) differences between diagnostic groups, greater accuracy (IFS AUC = .80, FAB AUC = .75, p = .036) in detecting ED and marginally stronger correlations with neuropsychological measures. We found no statistically significant differences in the EOD group scores from baseline up to 6- or 12-months follow-up.

CONCLUSIONS

While both tests can detect EOD among memory clinic patients, the IFS may be more reliable in detecting ED than the FAB.

A Novel Computerized Flexible Attention Test in Detecting Executive Dysfunction of Patients with Early-Onset Cognitive Impairment and Dementia

OBJECTIVE

The number of computer-based cognitive tests has increased in recent years, but there is a need for tests focusing on the assessment of executive function (EF), as it can be crucial for the identification of early-onset neurodegenerative disorders. This study aims to examine the ability of the Flexible Attention Test (FAT), a new computer-based test battery for detecting executive dysfunction of early-onset cognitive impairment and dementia patients.

METHOD

We analyzed the FAT subtask results in memory clinic patients with cognitive symptom onset at ≤65 years. The patients were divided into four groups: early onset dementia (EOD, n = 48), mild cognitive impairment due to neurological causes (MCI-n, n = 34), MCI due to other causes (MCI-o, n = 99), and subjective cognitive decline (SCD, n = 14). The test accuracy to distinguish EOD patients from other groups was examined, as well as correlations with pen-and-paper EF tests. We also reported the 12-months follow-up results.

RESULTS

The EOD and MCI-n patients performed significantly poorer (p ≤ .002) than those in the MCI-o and SCD groups in most of the FAT subtasks. The accuracies of the FAT subtasks to detect EOD from other causes were mainly moderate (0.34 ≤ area under the curve < 0.74). The FAT subtasks correlated logically with corresponding pen-and-paper EF tests (.15 ≤ r ≤ .75). No systematic learning effects were detected in the FAT performance at follow-up.

CONCLUSIONS

The FAT appears to be a promising method for the precise evaluation of EF and applicable distinguishing early-onset neurodegenerative disorders from patients with other causes of cognitive problems.

Neuropsychological Profiles, Etiologies, and Medical Comorbidities in Early-Onset Dementia and Cognitive Impairment: A Memory Outpatient Clinic Cohort Study

Background

Although early-onset dementia (EOD) is associated with diagnostic challenges that differ from those of related to late-onset dementia, only limited studies have addressed the neuropsychological and health characteristics or specified the diagnoses underlying early-onset cognitive impairment in a real-world clinical setting.

Objective

To investigate the neuropsychological profiles, etiologies, and comorbidities of an unselected cohort of memory clinic patients (≤65 years at symptom onset).

Methods

The patients' (n = 210) diagnoses were determined based on comprehensive diagnostic workup. Medical comorbidities and neuropsychological profiles were compared between clinically relevant patient groups, namely early-onset dementia (n = 55), mild cognitive impairment due to vascular or suspected neurodegenerative (MCI-n, n = 35) or non-neurodegenerative (MCI-o, n = 106) etiologies, and subjective cognitive decline (n = 14).

Results

The most prevalent diagnoses were Alzheimer's disease (AD, 14%) and depression (11%). Multiple prior medical conditions were common (67%); however, EOD patients had fewer other diagnoses (p = 0.008) than MCI-o patients. Compared to other groups, EOD patients had more severe deficits (p < 0.001) on immediate and delayed memory, processing speed, symptom awareness, and global cognition. AD patients had weaker memory retention ability but less behavioral symptoms than frontotemporal dementia (FTD) patients (p≤0.05). Depression was associated with better immediate memory, symptom awareness, and global cognition than AD and FTD (p < 0.05).

Conclusions

EOD is associated with more severe and widespread neuropsychological deficits but fewer prior medical diagnoses than nondegenerative etiologies of cognitive impairment. AD and depression are common etiologies and the neuropsychological profiles are partly overlapping; however, memory, symptom awareness and global cognitive impairment measures may help in the differential diagnosis.

The Cognitive Function at Work Questionnaire (CFWQ): A new scale for measuring cognitive complaints in occupational population

Cognitive functioning is a relevant work and health related topic, however, validated methods to assess subjective cognitive complaints (SCC) at work are lacking. We introduce the Cognitive Function at Work Questionnaire (CFWQ) for measuring SCC in occupational settings. 1-year follow-up data of 418 employees from a Finnish public media service company was analyzed. Participants completed web-based CFWQ, cognitive tests and a broad set of questionnaires for evaluating depression, anxiety, insomnia, daytime sleepiness, burnout, stress, mental job burden, work ability, cognitive errors, and perceived health. The factor analysis yielded a model with the CFWQ subdomains: Memory, Language, Executive Function, Speed of Processing, Cognitive Control and Name Memory. The internal consistency (Cronbach's alpha = .87) and the test-retest constancy (ICC = .84) reflected good reliability. Correlation between the CFWQ and cognitive errors at work ranged from .25 to .64 indicating adequate concurrent validity. Employees with depression, insomnia and burnout symptoms had higher (p < .001) CFWQ scores than participants without these symptoms. Depression and burnout symptom severity as well as accumulation of mood, sleep, and psychosocial stressors were associated with higher CFWQ scores (p < .001 in all). The CFWQ appears psychometrically sound measure for the assessment of SCC in occupational population.

Correlation of fatigue with disability and accelerometer-measured daily physical activity in patients with relapsing-remitting MS

BACKGROUND

Fatigue is one of the most common symptoms in patients with multiple sclerosis (MS). Furthermore, measuring its effects on patients in daily life is challenging. This study aimed to discover the association between relapsing-remitting MS (RRMS) patients' disability, fatigue, and accelerometer-measured physical activity.

METHODS

A total of 41 patients with RRMS with an Expanded Disability Status Scale (EDSS) level of 0-5.5 and 20 healthy controls completed the Modified Fatigue Impact Scale (MFIS) and the Fatigue Severity Scale (FSS) questionnaires. The EDSS was evaluated for all patients with RRMS, and all participants performed the MS Functional Composite (MSFC) test and six-min walk test and wore an accelerometer for seven days.

RESULTS

Patients with an EDSS level of 0-2.5 were found to have higher fatigue levels (p < 0.001) than healthy controls but lower levels than patients with an EDSS level of 3-5.5 (p < 0.001). A significant correlation was found to exist between fatigue and disability level measured by the EDSS (EDSS/FSS, r=0.750/p=0.001; EDSS/MFIS, r=0.661/p=0.001) and with the MSFC test in the patient group (MSFC/FSS, r = -0.350 p=0.025; MSFC/MFIS, r = -0.423/p=0.007). Total daily activity correlated with fatigue as measured by the FSS (MVPS/FSS r = -0.357/p=0.028, step count/FSS r = -0.463/p=0.003), but no correlation was found between the EDSS or the MSFC.

CONCLUSION

A lower disability rate, better physical condition, and higher daily-living activity were found to predict lower fatigue levels.

Fatigue and health-related quality of life depend on the disability status and clinical course in RRMS

BACKGROUND

Fatigue is a prominent and disabling symptom of multiple sclerosis (MS), impairing quality of life. The disease course of relapsing remitting MS (RRMS) is individual.

OBJECTIVES

We aimed to study the effects of demographic and clinical characteristics, as well as lifestyle risk factors on experienced fatigue and health-related quality of life (HRQoL) among RRMS patients, comparing benign and severe disease types.

METHODS

Altogether 198 Finnish RRMS patients were recruited for this real-life cross-sectional study. Self-reported questionnaires were used to evaluate fatigue and HRQoL by using Fatigue Scale for Motor and Cognitive Functions and 15D health-related quality of life questionnaires. Patients were categorized into subgroups based on the current disability status measured by the Expanded Disability Status Scale (EDSS) cut-off value of 4.5, and by retrospective clinical course divided into benign and aggressive RRMS.

RESULTS

All in all, 73% of the RRMS patients suffered from fatigue. Lower HRQoL had a strong correlation with more prominent fatigue (r = -0.719). Higher EDSS was associated with more prominent fatigue and lower HRQoL in the whole RRMS cohort. Older age at the disease onset was associated with more prominent fatigue and decreased HRQoL in the groups of aggressive RRMS and EDSS > 4.5. In the groups of EDSS ≤ 4.5 and benign RRMS, a higher number of used disease-modifying treatments (DMTs) was associated with more pronounced fatigue and reduced HRQoL. In addition, higher BMI was associated with lower HRQoL in patients with benign RRMS. Side effects (45 %) and lack of efficacy (26 %) were the most common reasons for discontinuing a DMT. Cessation due to side effects was the only reason that was significantly associated with more prominent fatigue and lower HRQoL. Use of nicotine products, gender, or disease duration were not associated with fatigue or HRQoL.

CONCLUSIONS

Individuals with severe RRMS and higher EDSS scores are more prone to experience fatigue and lower HRQoL. In addition, fatigue and lower HRQoL are more commonly observed among RRMS patients with older age at disease onset and in those with multiple DMT switches.

The Cognitive Function at Work Questionnaire in memory clinic setting: a validation study

INTRODUCTION

As there is a trend toward more people seeking medical help due to cognitive symptoms, validated and targeted questionnaires are increasingly important in the clinical evaluation process. The Cognitive Function at Work Questionnaire (CFWQ) was developed to identify and rate subjective cognitive symptoms of individuals active in working life. However, its psychometric characteristics have not been previously studied in a memory clinic setting.

METHOD

The factorial structure, internal consistency, test-retest reliability, and convergent validity of the CFWQ were studied in a memory clinic setting (N = 113). We also investigated the instrument's ability to identify cognitive symptoms in a cohort of early-onset dementia (EOD, N = 22), mild cognitive impairment-neurological (MCI-n, N = 18), MCI due to mood, sleep, or other physical health problems (MCI-o, N = 59), and subjective cognitive decline (SCD, N = 14) patients.

RESULTS

Based on factor analysis, eight cognitive subscales were identified covering main cognitive domains: Memory, Language, Executive Function, Speed of Processing, Cognitive Control, Name Memory, Visuospatial/Praxis and Attention. The internal consistency (α = .93) and the test-retest reliability (ICC = .91) were high. Several correlations (r = .19 - .33, p < .05) were documented between neuropsychological impairment level and CFWQ scores. EOD, MCI-n, MCI-o, and SCD groups did not differ statistically significantly in the levels of cognitive symptoms as measured by the CFWQ Total score. EOD group scored higher (p = .009) than other patient groups on the Visuospatial/Praxis subscale, but the difference between EOD and MCI-o groups turned insignificant after correcting for multiple testing.

CONCLUSIONS

The results of the study support the validity and reliability characteristics of the CFWQ in a memory clinic setting. The instrument is easy-to-use and has clinical utility in capturing the subjective cognitive symptoms of patients active in working life and who need a referral to a more detailed evaluation.

Serum Cathepsin S Levels Do Not Show Alterations in Different Clinical, Neuropathological, or Genetic Subtypes of Frontotemporal Dementia Patients nor in Comparison to Healthy Control Individuals

Frontotemporal dementia (FTD) can manifest as diverse clinical phenotypes and is frequently caused by mutations in different genes, complicating differential diagnosis. This underlines the urgent need for valid biomarkers. Altered lysosomal and immune functions proposedly contribute to FTD pathogenesis. Cathepsins, including cathepsin S, are enzymes preferentially expressed in brain in microglia, which influence lysosomal and immune function. Here, we examined whether alterations in serum cathepsin S levels associate with specific clinical, genetic, or neuropathological FTD subgroups, but no such alterations were observed. However, further research on other lysosomal proteins may reveal new biologically relevant biomarkers in FTD.

Cerebellar and subcortical atrophy contribute to psychiatric symptoms in frontotemporal dementia

Recent studies have reported early cerebellar and subcortical impact in the disease progression of genetic frontotemporal dementia (FTD) due to microtubule-associated protein tau (MAPT), progranulin (GRN) and chromosome 9 open reading frame 72 (C9orf72). However, the cerebello-subcortical circuitry in FTD has been understudied despite its essential role in cognition and behaviors related to FTD symptomatology. The present study aims to investigate the association between cerebellar and subcortical atrophy, and neuropsychiatric symptoms across genetic mutations. Our study included 983 participants from the Genetic Frontotemporal dementia Initiative including mutation carriers and noncarrier first-degree relatives of known symptomatic carriers. Voxel-wise analysis of the thalamus, striatum, globus pallidus, amygdala, and the cerebellum was performed, and partial least squares analyses (PLS) were used to link morphometry and behavior. In presymptomatic C9orf72 expansion carriers, thalamic atrophy was found compared to noncarriers, suggesting the importance of this structure in FTD prodromes. PLS analyses demonstrated that the cerebello-subcortical circuitry is related to neuropsychiatric symptoms, with significant overlap in brain/behavior patterns, but also specificity for each genetic mutation group. The largest differences were in the cerebellar atrophy (larger extent in C9orf72 expansion group) and more prominent amygdalar volume reduction in the MAPT group. Brain scores in the C9orf72 expansion carriers and MAPT carriers demonstrated covariation patterns concordant with atrophy patterns detectable up to 20 years before expected symptom onset. Overall, these results demonstrated the important role of the subcortical structures in genetic FTD symptom expression, particularly the cerebellum in C9orf72 and the amygdala in MAPT carriers.

Incidence of Syndromes Associated With Frontotemporal Lobar Degeneration in 9 European Countries

Importance

Diagnostic incidence data for syndromes associated with frontotemporal lobar degeneration (FTLD) in multinational studies are urgent in light of upcoming therapeutic approaches.

Objective

To assess the incidence of FTLD across Europe.

Design, Setting, and Participants

The Frontotemporal Dementia Incidence European Research Study (FRONTIERS) was a retrospective cohort study conducted from June 1, 2018, to May 31, 2019, using a population-based registry from 13 tertiary FTLD research clinics from the UK, the Netherlands, Finland, Sweden, Spain, Bulgaria, Serbia, Germany, and Italy and including all new FTLD-associated cases during the study period, with a combined catchment population of 11 023 643 person-years. Included patients fulfilled criteria for the behavioral variant of frontotemporal dementia (BVFTD), the nonfluent variant or semantic variant of primary progressive aphasia (PPA), unspecified PPA, progressive supranuclear palsy, corticobasal syndrome, or frontotemporal dementia with amyotrophic lateral sclerosis (FTD-ALS). Data were analyzed from July 19 to December 7, 2021.

Main Outcomes and Measures

Random-intercept Poisson models were used to obtain estimates of the European FTLD incidence rate accounting for geographic heterogeneity.

Results

Based on 267 identified cases (mean [SD] patient age, 66.70 [9.02] years; 156 males [58.43%]), the estimated annual incidence rate for FTLD in Europe was 2.36 cases per 100 000 person-years (95% CI, 1.59-3.51 cases per 100 000 person-years). There was a progressive increase in FTLD incidence across age, reaching its peak at the age of 71 years, with 13.09 cases per 100 000 person-years (95% CI, 8.46-18.93 cases per 100 000 person-years) among men and 7.88 cases per 100 000 person-years (95% CI, 5.39-11.60 cases per 100 000 person-years) among women. Overall, the incidence was higher among men (2.84 cases per 100 000 person-years; 95% CI, 1.88-4.27 cases per 100 000 person-years) than among women (1.91 cases per 100 000 person-years; 95% CI, 1.26-2.91 cases per 100 000 person-years). BVFTD was the most common phenotype (107 cases [40.07%]), followed by PPA (76 [28.46%]) and extrapyramidal phenotypes (69 [25.84%]). FTD-ALS was the rarest phenotype (15 cases [5.62%]). A total of 95 patients with FTLD (35.58%) had a family history of dementia. The estimated number of new FTLD cases per year in Europe was 12 057.

Conclusions and Relevance

The findings suggest that FTLD-associated syndromes are more common than previously recognized, and diagnosis should be considered at any age. Improved knowledge of FTLD incidence may contribute to appropriate health and social care planning and in the design of future clinical trials.

Traumatic Brain Injury Associates with an Earlier Onset in Sporadic Frontotemporal Dementia

BACKGROUND

Currently, there are few studies considering possible modifiable risk factors of frontotemporal dementia (FTD).

OBJECTIVE

In this retrospective case-control study, we evaluated whether a history of traumatic brain injury (TBI) associates with a diagnosis of FTD or modulates the clinical phenotype or onset age in FTD patients.

METHODS

We compared the prevalence of prior TBI between individuals with FTD (N = 218) and age and sex-matched AD patients (N = 214) or healthy controls (HC; N = 100). Based on the patient records, an individual was categorized to the TBI+ group if they were reported to have suffered from TBI during lifetime. The possible associations of TBI with age of onset and disease duration were also evaluated in the whole FTD patient group or separately in the sporadic and genetic FTD groups.

RESULTS

The prevalence of previous TBI was the highest in the FTD group (19.3%) when compared to the AD group (13.1%, p = 0.050) or HC group (12%, p = 0.108, not significant). Preceding TBI was more often associated with the sporadic FTD cases than the C9orf72 repeat expansion-carrying FTD cases (p = 0.003). Furthermore, comparison of the TBI+ and TBI- FTD groups indicated that previous TBI was associated with an earlier onset age in the FTD patients (B = 3.066, p = 0.010).

CONCLUSION

A preceding TBI associates especially with sporadic FTD and with earlier onset of symptoms. The results of this study suggest that TBI may be a triggering factor for the neurodegenerative processes in FTD. However, understanding the precise underlying mechanisms still needs further studies.

Psychopharmacological Medication Use in Frontotemporal Dementia at the Time of Diagnosis: Comparison with Alzheimer's Disease

BACKGROUND

Due to the significant presence of neuropsychiatric symptoms in patients with frontotemporal dementia (FTD) spectrum disorders, psychiatric misdiagnoses, diagnostic delay, and use of psychiatric treatments are common prior to the FTD diagnosis. Furthermore, treatment of diagnosed FTD patients mainly relies on off-label psychopharmacological approaches. Currently, limited real-world data are available regarding the actual use of psychopharmacological medications in FTD.

OBJECTIVE

To evaluate psychopharmacological medication use at the time of FTD diagnosis.

METHODS

Psychopharmacological medication use was evaluated in a Finnish FTD cohort containing 222 FTD patients, including the major clinical disease phenotypes (behavioral, language, and motor variants) and genetic patients carrying the C9orf72 repeat expansion. A cohort of 214 Alzheimer's disease (AD) patients was used as a neurodegenerative disease reference group.

RESULTS

Active use of psychopharmacological medications at the time of diagnosis was significantly more common in FTD compared to AD, especially in the case of antidepressants (26.1% versus 15.0%, OR = 2.01, p = 0.008), antipsychotics (23.9% versus 9.3%, OR = 3.15, p < 0.001), and mood-stabilizers (6.3% versus 1.9%, OR = 2.93, p = 0.085; not statistically significant), whereas the use of cholinesterase inhibitors or memantine was nearly nonexistent in FTD patients. Female gender and behavioral variant of FTD phenotype alongside with depressive and psychotic symptoms were the most prominent factors associating with the use of these medications among the FTD spectrum patients.

CONCLUSION

Use of off-label psychopharmacological medication and polypharmacy is substantially common at the time of FTD diagnosis. This likely reflects the challenges in using symptom-driven treatment approaches, especially prior to the eventual diagnosis.

Serum total TDP-43 levels are decreased in frontotemporal dementia patients with C9orf72 repeat expansion or concomitant motoneuron disease phenotype

BACKGROUND

Frontotemporal dementia (FTD) covers a spectrum of neurodegenerative disorders with various clinical and neuropathological subtypes. The two major pathological proteins accumulating in the brains of FTD patients, depending on their genetic background, are TDP-43 and tau. We aimed to evaluate whether total TDP-43 levels measured from the serum associate with the genotype or clinical phenotype of the FTD patients and whether serum TDP-43 provides prognostic or diagnostic value in the FTD spectrum disorders.

METHODS

The study cohort included 254 participants with a clinical diagnosis of FTD (including all major genotypes and clinical phenotypes) and 105 cognitively healthy controls. Serum total TDP-43 levels measured with a single-molecule array (Simoa) were compared within the FTD group according to the genotype, clinical phenotype, and predicted neuropathological subtype of the patients. We also evaluated the associations between the TDP-43 levels and disease severity or survival in FTD.

RESULTS

Total TDP-43 levels in the serum were significantly lower in the FTD group as compared to the healthy control group (275.3 pg/mL vs. 361.8 pg/mL, B = 0.181, 95%CI = 0.014-0.348, p = 0.034). The lowest TDP-43 levels were observed in the subgroup of FTD patients harboring predicted TDP-43 brain pathology (FTD-TDP, 241.4 pg/mL). The low levels in the FTD-TDP group were especially driven by C9orf72 repeat expansion carriers (169.2 pg/mL) and FTD patients with concomitant motoneuron disease (FTD-MND, 113.3 pg/mL), whereas GRN mutation carriers did not show decreased TDP-43 levels (328.6 pg/mL). Serum TDP-43 levels showed no correlation with disease severity nor progression in FTD.

CONCLUSIONS

Our results indicate that the total levels of TDP-43 in the serum are decreased especially in FTD patients with the C9orf72 repeat expansion or FTD-MND phenotype, both subtypes strongly associated with TDP-43 type B brain pathology. Serum-based measurement of TDP-43 could represent a useful tool in indicating C9orf72 repeat expansion and FTD-MND-related TDP-43 neuropathology for future diagnostics and intervention studies.

Cognitive impairment is not uncommon in patients with biallelic RFC1 AAGGG repeat expansion, but the expansion is rare in patients with cognitive disease

INTRODUCTION

The biallelic repeat expansion (AAGGG)_exp in RFC1 causes cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS). Recently, cognitive impairment has been reported in patients with CANVAS and a broader neurodegenerative process associated with RFC1 has been suggested. Furthermore, rare cases of multiple system atrophy, Parkinson's disease, amyotrophic lateral sclerosis or CANVAS with features of dementia with Lewy bodies have been found.

OBJECTIVE

We hypothesized that the biallelic (AAGGG)_exp is associated with neurodegeneration manifested as cognitive symptoms and that atypical RFC1 disease may be found among patients with cognitive disorder.

METHODS

Clinical data on nine patients with biallelic (AAGGG)_exp were reviewed and 564 patients with Alzheimer's disease or frontotemporal dementia (FTD) were investigated for biallelic RFC1 (AAGGG)_exp.

RESULTS

Five patients with biallelic (AAGGG)_exp were found with a cognitive impairment and in four of them the phenotype resembled FTD. However, biallelic (AAGGG)_exp was not detected among patients with Alzheimer's disease or FTD.

CONCLUSION

Cognitive impairment is a feature in patients with the biallelic (AAGGG)_exp, but the pathogenic expansion seems to be rare in patients with dementia. Studies on patients with diverse phenotypes would be useful to further explore the involvement of RFC1 in neuronal degeneration and to identify atypical phenotypes, which should be taken into account in clinical practice.

Grey matter atrophy in patients with benign multiple sclerosis

BACKGROUND

Brain atrophy appears during the progression of multiple sclerosis (MS) and is associated with the disability caused by the disease.

METHODS

We investigated global and regional grey matter (GM) and white matter (WM) volumes, WM lesion load, and corpus callosum index (CCI), in benign relapsing-remitting MS (BRRMS, n = 35) with and without any treatment and compared those to aggressive relapsing-remitting MS (ARRMS, n = 46). Structures were analyzed by using an automated MRI quantification tool (cNeuro®).

RESULTS

The total brain and cerebral WM volumes were larger in BRRMS than in ARRMS (p = .014, p = .017 respectively). In BRRMS, total brain volumes, regional GM volumes, and CCI were found similar whether or not disease-modifying treatment (DMT) was used. The total (p = .033), as well as subcortical (p = .046) and deep WM (p = .041) lesion load volumes were larger in BRRMS patients without DMT. Cortical GM volumes did not differ between BRRMS and ARRMS, but the volumes of total brain tissue (p = .014) and thalami (p = .003) were larger in patients with BRRMS compared to ARRMS. A positive correlation was found between CCI and whole-brain volume in both BRRMS (r = .73, p < .001) and ARRMS (r = .80, p < .01).

CONCLUSIONS

Thalamic volume is the most prominent measure to differentiate BRRMS and ARRMS. Validation of automated quantification of CCI provides an additional applicable MRI biomarker to detect brain atrophy in MS.

Modifiable potential risk factors in familial and sporadic frontotemporal dementia

Objective

Only a few studies have evaluated modifiable risk factors for frontotemporal dementia (FTD). Here, we evaluated several modifiable factors and their association with disease phenotype, genotype, and prognosis in a large study population including Finnish and Italian patients with FTD and control groups.

Methods

In this case–control study, we compared the presence of several cardiovascular and other lifestyle‐related diseases and education between Finnish and Italian patients with familial (n = 376) and sporadic (n = 654) FTD, between different phenotypes of FTD, and between a subgroup of Finnish FTD patients (n = 221) and matched Finnish patients with Alzheimer's disease (AD) (n = 214) and cognitively healthy controls (HC) (n = 100).

Results

Patients with sporadic FTD were less educated (p = 0.042, B = ‐0.560, 95% CI −1.101 to −0.019) and had more heart diseases (p < 0.001, OR = 2.265, 95% CI 1.502–3.417) compared to patients with familial FTD. Finnish FTD patients were less educated (p = 0.032, B = 0.755, 95% CI 0.064–1.466) compared with AD patients. The Finnish FTD group showed lower prevalence of hypertension than the HC group (p = 0.003, OR = 2.162, 95% CI 1.304–3.583) and lower prevalence of hypercholesterolemia than in the HC group (p < 0.001, OR = 2.648, 95%CI 1.548–4.531) or in the AD group (p < 0.001, OR = 1.995, 95% CI 1.333–2.986). Within the FTD group, clinical phenotypes also differed regarding education and lifestyle‐related factors.

Interpretation

Our study suggests distinct profiles of several modifiable factors in the FTD group depending on the phenotype and familial inheritance history and that especially sporadic FTD may be associated with modifiable risk factors.

Brainstem atrophy is linked to extrapyramidal symptoms in frontotemporal dementia

Extrapyramidal (EP) symptoms are a known feature in a subpopulation of patients with behavioral variant frontotemporal dementia (bvFTD). Concomitant EP symptoms with FTD-like neuropsychiatric symptoms are also core features in progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). This complicates the early diagnosis of these disorders. Our retrospective register study aimed to discover imaging (MRI and FDG-PET) biomarkers to differentiate PSP, CBD, and bvFTD patients with extrapyramidal symptoms (EP +) from bvFTD patients without EP symptoms (EP-). The records of 2751 patients were screened for the diagnoses and presence of EP symptoms. A total of 222 patients were submitted to imaging analysis and applicable imaging data were recovered from 139 patients. Neuroimaging data were analyzed using Freesurfer software. In the whole cohort, EP + patients showed lower volumes of gray matter compared to EP- patients in the putamen (p = 0.002), bilateral globus pallidum (p = 0.002, p = 0.042), ventral diencephalon (p = 0.002) and brain stem (p < 0.001). In the bvFTD subgroup, there was volumetric difference between EP + and EP− patients in the brain stem. FDG-PET scans in the bvFTD patient subgroup showed that EP + patients had comparative hypometabolism of the superior cerebellar peduncle (SCP) and the frontal lobes. We discovered that EP symptoms are linked to brainstem atrophy in bvFTD patients and the whole cohort. Also, evident hypometabolism in the SCP of bvFTD EP + patients was detected as compared to bvFTD EP− patients. This could indicate that the EP symptoms in these diseases have a more caudal origin in the brainstem than in Parkinson’s disease.

Cerebrospinal fluid biomarkers that reflect clinical symptoms in idiopathic normal pressure hydrocephalus patients

Background

The relationship between cerebrospinal fluid (CSF) biomarkers and the clinical features of idiopathic normal pressure hydrocephalus (iNPH) has been inconclusive. We aimed to evaluate CSF biomarkers reflecting Alzheimer’s disease (AD)-related amyloid β (Aβ) aggregation, tau pathology, neuroinflammation and axonal degeneration in relation to the clinical features of pre- and post-shunt surgery in iNPH patients.

Methods

Mini Mental State Examination (MMSE) scores and gait velocity were evaluated pre- and postoperatively in cohorts of 65 Finnish (FIN) and 82 Swedish (SWE) iNPH patients. Lumbar CSF samples were obtained prior to shunt surgery and analysed for soluble amyloid precursor protein alpha (sAPPα) and beta (sAPPβ); amyloid-β isoforms of 42, 40 and 38 (Aβ₄₂, Aβ₄₀, Aβ₃₈); total tau (T-tau); phosphorylated tau (P-tau₁₈₁); neurofilament light (NfL) and monocyte chemoattractant protein 1 (MCP1).

Results

Preoperative patient characteristics showed no significant differences between patients in the FIN and SWE cohorts. Patients in both cohorts had significantly improved gait velocity after shunt surgery (p < 0.0001). Low CSF T-tau and absence of apolipoprotein E ε4 predicted over 20% gait improvement postoperatively (p = 0.043 and p = 0.008). Preoperative CSF T-tau, P-tau₁₈₁ and NfL correlated negatively with MMSE scores both pre- (p < 0.01) and post-surgery (p < 0.01). Furthermore, T-tau, NfL and Aβ₄₂ correlated with MMSE outcomes (p < 0.05). Low preoperative CSF P-tau₁₈₁ (p = 0.001) and T-tau with NfL (p < 0.001 and p = 0.049) best predicted pre- and postoperative MMSE scores greater than or equal to 26.

Conclusions

CSF biomarkers of neurodegeneration appeared to correlate with pre- and postoperative cognition, providing a window into neuropathological processes. In addition, preoperative CSF neurodegeneration biomarkers may have potential in the prediction of gait and cognitive outcomes after shunt surgery.

Deficient neurotransmitter systems and synaptic function in frontotemporal lobar degeneration-Insights into disease mechanisms and current therapeutic approaches

Frontotemporal lobar degeneration (FTLD) comprises a heterogenous group of fatal neurodegenerative diseases and, to date, no validated diagnostic or prognostic biomarkers or effective disease-modifying therapies exist for the different clinical or genetic subtypes of FTLD. Current treatment strategies rely on the off-label use of medications for symptomatic treatment. Changes in several neurotransmitter systems including the glutamatergic, GABAergic, dopaminergic, and serotonergic systems have been reported in FTLD spectrum disease patients. Many FTLD-related clinical and neuropsychiatric symptoms such as aggressive and compulsive behaviour, agitation, as well as altered eating habits and hyperorality can be explained by disturbances in these neurotransmitter systems, suggesting that their targeting might possibly offer new therapeutic options for treating patients with FTLD. This review summarizes the present knowledge on neurotransmitter system deficits and synaptic dysfunction in model systems and patients harbouring the most common genetic causes of FTLD, the hexanucleotide repeat expansion in C9orf72 and mutations in the granulin (GRN) and microtubule-associated protein tau (MAPT) genes. We also describe the current pharmacological treatment options for FLTD that target different neurotransmitter systems.

C9orf72 hexanucleotide repeat expansion leads to altered neuronal and dendritic spine morphology and synaptic dysfunction

Frontotemporal lobar degeneration (FTLD) comprises a heterogenous group of progressive neurodegenerative syndromes. To date, no validated biomarkers or effective disease-modifying therapies exist for the different clinical or genetic subtypes of FTLD. The most common genetic cause underlying FTLD and amyotrophic lateral sclerosis (ALS) is a hexanucleotide repeat expansion in the C9orf72 gene (C9-HRE). FTLD is accompanied by changes in several neurotransmitter systems, including the glutamatergic, GABAergic, dopaminergic, and serotonergic systems and many clinical symptoms can be explained by disturbances in these systems. Here, we aimed to elucidate the effects of the C9-HRE on synaptic function, molecular composition of synapses, and dendritic spine morphology. We overexpressed the pathological C9-HRE in cultured E18 mouse primary hippocampal neurons and characterized the pathological, morphological, and functional changes by biochemical methods, confocal microscopy, and live cell calcium imaging. The C9-HRE-expressing neurons were confirmed to display the pathological RNA foci and DPR proteins. C9-HRE expression led to significant changes in dendritic spine morphologies, as indicated by decreased number of mushroom-type spines and increased number of stubby and thin spines, as well as diminished neuronal branching. These morphological changes were accompanied by concomitantly enhanced susceptibility of the neurons to glutamate-induced excitotoxicity as well as augmented and prolonged responses to excitatory stimuli by glutamate and depolarizing potassium chloride as compared to control neurons. Mechanistically, the hyperexcitation phenotype in the C9-HRE-expressing neurons was found to be underlain by increased activity of extrasynaptic GluN2B-containing N-methyl-d-aspartate (NMDA) receptors. Our results are in accordance with the idea suggesting that C9-HRE is associated with enhanced excitotoxicity and synaptic dysfunction. Thus, therapeutic interventions targeted to alleviate synaptic disturbances might offer efficient avenues for the treatment of patients with C9-HRE-associated FTLD.

GFAP as a biomarker in frontotemporal dementia and primary psychiatric disorders: diagnostic and prognostic performance

BACKGROUND

Frontotemporal lobar degeneration (FTLD) and primary psychiatric disorders (PPD) are characterised by overlapping clinical features but different aetiologies. Here, we assessed for the first time the potential of blood glial fibrillar acidic protein (GFAP), marker of astrogliosis, as a discriminative and prognostic tool in FTLD and PPD.

METHODS

The levels of GFAP in serum (sGFAP) of patients with FTLD (N=107) and PPD (N=44) and GFAP in whole blood samples (bGFAP) from FTLD (N=10), PPD (N=10) and healthy controls (N=18) were measured. We evaluated whether the sGFAP levels associate with C9orf72 repeat expansion, survival of FTLD and PPD patients, and brain atrophy assessed cross-sectionally and longitudinally by structural T1W MRI. We also examined the correlation between sGFAP and bGFAP levels in a subset of patients.

RESULTS

sGFAP and bGFAP levels were elevated in the FTLD group compared with the PPD or control groups. Receiver operating characteristic analysis indicated an excellent diagnostic performance between FTLD and PPD (the area under the curve (AUC)=0.820, 95% CI 0.745 to 0.896). sGFAP and bGFAP levels showed a strong correlation and elevated sGFAP levels significantly associated with atrophy rate in the temporal cortex and predicted shorter survival time in patients with FTLD. No association with C9orf72 repeat expansion was detected.

CONCLUSIONS

sGFAP enabled differentiation of patients with FTLD and PPD and associated with shorter survival and more severe brain atrophy rate in patients with FTLD. These results suggest that blood-based GFAP represents a minimally invasive and useful biomarker in the differential diagnostics between patients with FTLD and PPD and in evaluating disease progression and astrogliosis in FTLD.

Primary progressive aphasias associated with C9orf72 expansions: Another side of the story

C9orf72 repeat expansions are rarely associated with primary progressive aphasias (PPA). In-depth characterization of the linguistic deficits, and the underlying patterns of grey-matter atrophy in PPA associated with the C9orf72 expansions (PPA-C9orf72) are currently lacking. In this study, we comprehensively analyzed a unique series of 16 patients affected by PPA-C9orf72. Eleven patients were issued from two independent French and Finnish cohorts, and five were identified by means of literature review. Voxel-based morphometry (VBM) studies were performed on three of them. This study depicts the spectrum of C9orf72-related aphasic phenotypes, and illustrates their linguistic presentation. The non-fluent/agrammatic variant was the most frequent phenotype in our series (9/16 patients, 56%), with apraxia of speech being the main defining feature. Left frontal lobe atrophy was present in these subjects, peaking in inferior frontal gyrus. Three patients (19%) showed the semantic variant, with progression of atrophy in temporo-polar regions, later involving orbitofrontal cortex. Anterior temporal lobe dysfunction was also particularly relevant in two patients (12.5%) with mixed forms of PPA. Lastly, two patients (12.5%) had unclassifiable PPA with predominating word-finding difficulties. No PPA-C9orf72 patients in our series fulfilled the criteria of the logopenic variant. Importantly, this study underlines the role of C9orf72 mutation in the disruption of the most anterior parts of the language network, including prefrontal and temporo-polar areas. It provides guidelines for C9orf72 testing in PPA patients, with important clinical impact as gene-specific therapies are upcoming.

Serum GFAP and NfL levels in benign relapsing-remitting multiple sclerosis

OBJECTIVE

We aimed to investigate serum glial fibrillary acidic protein (GFAP) and serum neurofilament light chain (NfL) levels as potential discriminative biomarkers between benign relapsing-remitting multiple sclerosis (BRRMS) and aggressive relapsing-remitting MS (ARRMS).

METHODS

Serum GFAP and NfL levels were analyzed in patients with BRRMS (n = 34), ARRMS (n = 29), and healthy controls (n = 14) by using Single Molecule Array (Simoa). Patients with ARRMS had been treated with highly effective disease-modifying treatments (DMT) (fingolimod or natalizumab).

RESULTS

Serum GFAP levels in both BRRMS (median 210.19 pg/ml, IQR 163.69-287.19) and in ARRMS (median 188.60 pg/ml, IQR39.23-244.93) were significantly higher (p = 0.035 and p = 0.034, respectively) compared to healthy controls (median 117.93 pg/ml, IQR 60.28-183.83). Serum GFAP levels did not differ between BRRMS and ARRMS. There were no statistical differences in NfL levels between BRRMS, ARRMS and healthy controls. GFAP level was significantly higher (p = 0.04) in BRRMS without DMT (median 216.04 pg/ml, IQR 188.60-274.79) than in those BRRMS patients who had used DMT (median 196.26 pg/ml, IQR 133.33-325.54).

CONCLUSIONS

We found elevated levels of serum GFAP in both BRRMS and ARRMS compared to healthy controls, reflecting astrocytic activation. Serum NfL did not differ between BRRMS and ARRMS, probably due to the stable inflammatory phase of the disease and effective DMT use in ARRMS. Single serum NfL and GFAP measurements cannot separate a patient with BRRMS from effectively treated ARRMS after a long history of the disease, thus consecutive samples are needed in the follow-up.

A Novel Genetic Marker for the C9orf72 Repeat Expansion in the Finnish Population

BACKGROUND

C9orf72 repeat expansion (C9exp) is the most common genetic cause underlying frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). However, detection of the C9exp requires elaborative methods.

OBJECTIVE

Identification of C9exp carriers from genotyped cohorts could be facilitated by using single nucleotide polymorphisms (SNPs) as markers for the C9exp.

METHODS

We elucidated the potential of the previously described Finnish risk haplotype, defined by the SNP rs3849942, to identify potential C9exp carriers among 218,792 Finns using the FinnGen database. The haplotype approach was first tested in an idiopathic normal pressure hydrocephalus (iNPH) patient cohort (European Alzheimer's Disease DNA BioBank) containing C9exp carriers by comparing intermediate (15-30) and full-length (>  60 repeats) C9exp carriers (n = 41) to C9exp negative patients (<  15 repeats, n = 801).

RESULTS

In this analysis, rs3849942 was associated with carriership of C9exp (OR 8.44, p <  2×10-15), while the strongest association was found with rs139185008 (OR 39.4, p <  5×10-18). Unbiased analysis of rs139185008 in FinnGen showed the strongest association with FTLD (OR 4.38, 3×10-15) and motor neuron disease ALS (OR 5.19, 3×10-21). rs139185008 was the top SNP in all diseases (iNPH, FTLD, ALS), and further showed a strong association with ALS in the UK Biobank (p = 9.0×10-8).

CONCLUSION

Our findings suggest that rs139185008 is a useful marker to identify potential C9exp carriers in the genotyped cohorts and biobanks originating from Finland.

FRONTotemporal dementia Incidence European Research Study-FRONTIERS: Rationale and design

Introduction

The incidence of Frontotemporal Lobar Degeneration (FTLD)–related disorders and their characteristics are not well known. The “FRONTotemporal dementia Incidence European Research Study” (FRONTIERS) is designed to fill this gap.

Methods

FRONTIERS is a European prospective, observational population study based on multinational registries. FRONTIERS comprises 11 tertiary referral centers across Europe with long‐lasting experience in FTLD‐related disorders and comprehensive regional referral networks, enabling incidence estimation over well‐defined geographical areas.

Endpoints

The primary endpoints are (1) the incidence of FTLD‐related disorders across Europe; (2) geographic trends of FTLD‐related disorders; (3) the distribution of FTLD phenotypes in different populations and ethnicities in Europe; (4) inheritance of FTLD‐related disorders, including the frequencies of monogenic FTLD as compared to overall disease burden; and (5) implementation of data banking for clinical and biological material.

Expected impacts

FRONTIERS will improve the understanding of FTLD‐related disorders and their epidemiology, promoting appropriate public health service policies and treatment strategies.

FTLD Patient-Derived Fibroblasts Show Defective Mitochondrial Function and Accumulation of p62

Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and neuropathologically heterogeneous group of neurodegenerative syndromes, leading to progressive cognitive dysfunction and frontal and temporal atrophy. C9orf72 hexanucleotide repeat expansion (C9-HRE) is the most common genetic cause of FTLD, but pathogenic mechanisms underlying FTLD are not fully understood. Here, we compared cellular features and functional properties, especially related to protein degradation pathways and mitochondrial function, of FTLD patient–derived skin fibroblasts from C9-HRE carriers and non-carriers and healthy donors. Fibroblasts from C9-HRE carriers were found to produce RNA foci, but no dipeptide repeat proteins, and they showed unchanged levels of C9orf72 mRNA transcripts. The main protein degradation pathways, the ubiquitin–proteasome system and autophagy, did not show alterations between the fibroblasts from C9-HRE-carrying and non-carrying FTLD patients and compared to healthy controls. An increase in the number and size of p62-positive puncta was evident in fibroblasts from both C9-HRE carriers and non-carriers. In addition, several parameters of mitochondrial function, namely, basal and maximal respiration and respiration linked to ATP production, were significantly reduced in the FTLD patient–derived fibroblasts from both C9-HRE carriers and non-carriers. Our findings suggest that FTLD patient–derived fibroblasts, regardless of whether they carry the C9-HRE expansion, show unchanged proteasomal and autophagic function, but significantly impaired mitochondrial function and increased accumulation of p62 when compared to control fibroblasts. These findings suggest the possibility of utilizing FTLD patient–derived fibroblasts as a platform for biomarker discovery and testing of drugs targeted to specific cellular functions, such as mitochondrial respiration.

Novel Rare SORL1 Variants in Early-Onset Dementia

BACKGROUND

Rare variants of SORL1 have been associated with an increased risk of early-onset or late-onset Alzheimer's disease (AD). However, a lot remains to be clarified about their significance in the pathogenesis of the disease.

OBJECTIVE

To evaluate the role of SORL1 variants among Finnish patients with early-onset AD (EOAD).

METHODS

The rare SORL1variants were screened in a cohort of 115 Finnish EOAD patients (mean age at onset 58.3 years, range 46-65 years) by using the whole-exome sequencing.

RESULTS

We found one novel nonsense variant (p.Gln290*) and eight missense variants in SORL1. This is the first study reporting the SORL1 variants p.Lys80Arg, p.Ala789Val and p.Arg866Gln in EOAD patients. Furthermore, two of these three missense variants were overrepresented in EOAD patients compared to gnomAD non-neuro Finnish samples.

CONCLUSION

This study strengthens the earlier findings, that the rare variants in SORL1 are associated with EOAD.

Safety of alemtuzumab in a nationwide cohort of Finnish multiple sclerosis patients

Background

Alemtuzumab is an effective disease-modifying therapy (DMT) for highly active multiple sclerosis (MS). However, safety concerns limit its use in clinical practice.

Objectives

To evaluate the safety of alemtuzumab in a nationwide cohort of Finnish MS patients.

Methods

In this retrospective case series study, we analyzed the data of all but two MS patients who had received alemtuzumab in Finland until 2019. Data were systematically collected from patient files.

Results

Altogether 121 patients were identified, most of whom had received previous DMTs (82.6%). Median follow-up time after treatment initiation was 30.3 months and exceeded 24 months in 78 patients. Infusion-associated reactions (IARs) were observed in 84.3%, 57.3%, and 57.1% of patients during alemtuzumab courses 1–3, respectively. Serious adverse events (SAEs) were observed in 32.2% of patients, serious IARs in 12.4% of patients, and SAEs other than IARs in 23.1% of patients. Autoimmune adverse events were observed in 30.6% of patients. One patient died of hemophagocytic lymphohistiocytosis, and one patient died of pneumonia. A previously unreported case of thrombotic thrombocytopenic purpura was documented.

Conclusions

SAEs were more frequent in the present cohort than in previous studies. Even though alemtuzumab is a highly effective therapy for MS, vigorous monitoring with a long enough follow-up time is advised.

Mutation Analysis of the Genes Associated with Parkinson's Disease in a Finnish Cohort of Early-Onset Dementia

BACKGROUND

Alzheimer's disease, frontotemporal lobar degeneration, dementia with Lewy bodies, and Parkinson's disease (PD) overlap in clinical characteristics, neuropathology, and genetics.

OBJECTIVE

The aim of this study was to evaluate the role of pathogenic mutations and rare variants in genes associated with PD among early-onset dementia (EOD) patients.

METHODS

Rare non-synonymous variants (MAF < 0.01) in ten genes (SNCA, PARK2, PARK7, LRRK2, PINK1, ATP13A2, UCHL1, HTRA2, GBA, and SNCAIP) and low-frequency (MAF < 0.05) GBA variants were screened using a targeted next-generation sequencing panel in a strictly defined cohort of 37 early-onset (age at onset (AAO) <65 years) dementia patients presenting with atypical features (e.g., myoclonia or spasticity), rapidly progressive course of the disease or with a family history of dementia. The identified variations were further screened in a larger cohort of EOD (n = 279, mean AAO 57, range 36-65) patients.

RESULTS

No pathogenic mutations were found, but we identified seven possible risk variants for neurodegeneration (LRRK2 p.Arg793Met, PARK2 p.Ala82Glu, SNCAIP p.Arg240Gln, SNCAIP p.Phe369Leu, GBA p.Asn409Ser, GBA p.Glu365Lys, GBA p.Thr408Met).

DISCUSSION

Altogether, the frequency of these variants was two times higher in the first selected cohort compared to the whole cohort. This suggests that specific rare variants in the genes associated with PD might play a role also especially in familial EOD.

State-of-the-Art Methods and Emerging Fluid Biomarkers in the Diagnostics of Dementia-A Short Review and Diagnostic Algorithm

The most common neurodegenerative dementias include Alzheimer’s disease (AD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). The correct etiology-based diagnosis is pivotal for clinical management of these diseases as well as for the suitable timing and choosing the accurate disease-modifying therapies when these become available. Enzyme-linked immunosorbent assay (ELISA)-based methods, detecting altered levels of cerebrospinal fluid (CSF) Tau, phosphorylated Tau, and Aβ-42 in AD, allowed the wide use of this set of biomarkers in clinical practice. These analyses demonstrate a high diagnostic accuracy in AD but suffer from a relatively restricted usefulness due to invasiveness and lack of prognostic value. In recent years, the development of novel advanced techniques has offered new state-of-the-art opportunities in biomarker discovery. These include single molecule array technology (SIMOA), a tool for non-invasive analysis of ultra-low levels of central nervous system-derived molecules from biofluids, such as CSF or blood, and real-time quaking (RT-QuIC), developed to analyze misfolded proteins. In the present review, we describe the history of methods used in the fluid biomarker analyses of dementia, discuss specific emerging biomarkers with translational potential for clinical use, and suggest an algorithm for the use of new non-invasive blood biomarkers in clinical practice.

Cardiovascular brain impulses in Alzheimer's disease

Accumulation of amyloid-β is a key neuropathological feature in brain of Alzheimer’s disease patients. Alterations in cerebral haemodynamics, such as arterial impulse propagation driving the (peri)vascular CSF flux, predict future Alzheimer’s disease progression. We now present a non-invasive method to quantify the three-dimensional propagation of cardiovascular impulses in human brain using ultrafast 10 Hz magnetic resonance encephalography. This technique revealed spatio-temporal abnormalities in impulse propagation in Alzheimer’s disease. The arrival latency and propagation speed both differed in patients with Alzheimer’s disease. Our mapping of arterial territories revealed Alzheimer’s disease-specific modifications, including reversed impulse propagation around the hippocampi and in parietal cortical areas. The findings imply that pervasive abnormality in (peri)vascular CSF impulse propagation compromises vascular impulse propagation and subsequently glymphatic brain clearance of amyloid-β in Alzheimer’s disease.

Comparison of Prodromal Symptoms of Patients with Behavioral Variant Frontotemporal Dementia and Alzheimer Disease

INTRODUCTION

Behavioral variant frontotemporal dementia (bvFTD) is the most common clinical subtype of frontotemporal lobar degeneration. bvFTD is often characterized by changes in behavior and personality, frequently leading to psychiatric misdiagnoses. On the other hand, substantial clinical overlap with other neurodegenerative diseases, such as Alzheimer disease (AD), further complicates the diagnostics.

OBJECTIVE

Our aim was to identify the main differences in early symptoms of bvFTD and AD in the prodromal stages of the diseases. In addition, patients with bvFTD were analyzed separately according to whether they carry the C9orf72repeat expansion or not.

METHODS

Patient records of bvFTD (n = 75) and AD (n = 83) patients were analyzed retrospectively for memory and neuropsychiatric symptoms, sleeping disorders, and somatic complaints before the setting of the accurate diagnosis.

RESULTS

A total of 84% of bvFTD patients (n = 63) and 98.8% of AD patients (n = 82) reported subjective memory disturbances in the prodromal phases of the disease. bvFTD patients presented significantly more often with sleeping disorders, headache, inexplicable collapses, transient loss of consciousness, somatization, delusions, and hallucinations, suicidality, changes in oral behaviors, and urinary problems. In addition, poor financial judgement was frequently detected in patients with prodromal bvFTD. Aberrant sensations in the nose and throat without any physical explanation, regarded as somatizations, emerged only in bvFTD patients with the C9orf72 repeat expansion.

CONCLUSIONS

Subjective reporting of impaired episodic memory is a poor indicator in differentiating bvFTD from AD. Sleeping disturbances, delusions, hallucinations, and unexplained somatic complaints in a patient with cognitive disturbances should prompt the clinicians to consider bvFTD as a possible diagnostic option behind these symptoms. The spectrum of symptoms in the prodromal stages of bvFTD may be more diverse than the latest criteria suggest.

Severe Obstructive Sleep Apnea and Increased Cortical Amyloid-β Deposition

BACKGROUND

The suggested association between severe obstructive sleep apnea (OSA) and risk of Alzheimer's disease (AD) needs further study. Only few recent reports exist on associations between brain amyloid-β (Aβ) burden and severe OSA in middle-aged patients.

OBJECTIVE

Examine the possible presence of cortical Aβ accumulation in middle-aged patients with severe OSA.

METHODS

We performed detailed multimodal neuroimaging in 19 cognitive intact patients (mean 44.2 years) with severe OSA (Apnea-Hypopnea Index >30 h-1). Known etiological factors for possible Aβ accumulation were used as exclusion criteria. Aβ uptake was studied with [11C]-PiB-PET, glucose metabolism with [18F]-FDG-PET, and structural imaging with 3.0T MRI.

RESULTS

When analyzed individually, in [11C]-PiB-PET a substantial number (∼32%) of the patients exhibited statistically significant evidence of increased cortical Aβ uptake based on elevated regional Z-score values, mostly seen bilaterally in the precuneus and posterior cingulum regions. Cortical glucose hypometabolism in [18F]-FDG-PET was seen in two patients. MRI did not show structural changes suggestive of AD-related pathology.

CONCLUSION

Increased [11C]-PiB uptake was seen in middle-aged cognitively intact patients with severe OSA. These findings are similar to those described in cognitive unimpaired older OSA patients. The changes in cortical Aβ uptake suggest that severe OSA itself may predispose to alterations related to AD already in middle-age. Aβ clearance may be compromised without simultaneous evidence of metabolic or structural alterations. The results emphasize the importance of early diagnostics and proper treatment of severe OSA in cognitively intact middle-aged subjects, possibly diminishing the individual risk for later cognitive dysfunction.

The ethical implications of genetic testing in neurodegenerative diseases: A systematic review

BACKGROUND

Availability of genetic testing in neurodegenerative disorders has developed rapidly. This growing ability is providing specific genetic information to individuals and, in turn, their families, raising ethical concerns. However, family members' perspective is a seldom-studied phenomenon.

AIM

The aim of this systematic review was to describe the ethical aspect of genetic testing in neurodegenerative diseases from the perspective of at-risk family members.

METHOD

A systematic review of data was performed in accordance with the PRISMA statement. The data search was conducted using the CINAHL, PubMed and Scopus databases to identify original peer-reviewed studies published between January 2009 and April 2019. A total of 24 articles were selected. The data were analysed using inductive content analysis.

FINDINGS

On the basis of the analysis, four central ethical implications were identified: (i) decision-making in genetic testing as a dilemma: balance between autonomy and responsibility, (ii) the individual's right to make a voluntary and informed decision for genetic testing, (iii) conflicting emotions after knowing one's genetic status and (iv) privacy and confidentiality of genetic information: the fear of genetic discrimination and stigma.

CONCLUSIONS

The findings of this review increase understanding about the central ethical implications of genetic testing in neurodegenerative diseases from the perspective of family members, and identify and underline outstanding needs for further research.

Predicting Development of Alzheimer's Disease in Patients with Shunted Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) patients often develop Alzheimer's disease (AD) related brain pathology. Disease State Index (DSI) is a method to combine data from various sources for differential diagnosis and progression of neurodegenerative disorders.

OBJECTIVE

To apply DSI to predict clinical AD in shunted iNPH-patients in a defined population.

METHODS

335 shunted iNPH-patients (median 74 years) were followed until death (n = 185) or 6/2015 (n = 150). DSI model (including symptom profile, onset age of NPH symptoms, atrophy of medial temporal lobe in CT/MRI, cortical brain biopsy finding, and APOE genotype) was applied. Performance of DSI model was evaluated with receiver operating characteristic (ROC) curve analysis.

RESULTS

A total of 70 (21%) patients developed clinical AD during median follow-up of 5.3 years. DSI-model predicted clinical AD with moderate effectiveness (AUC = 0.75). Significant factors were cortical biopsy (0.69), clinical symptoms (0.66), and medial temporal lobe atrophy (0.66).

CONCLUSION

We found increased occurrence of clinical AD in previously shunted iNPH patients as compared with general population. DSI supported the prediction of AD. Cortical biopsy during shunt insertion seems indicated for earlier diagnosis of comorbid AD.

Low Serum High-Density Lipoprotein Cholesterol Levels Associate with the C9orf72 Repeat Expansion in Frontotemporal Lobar Degeneration Patients

 Decreased levels of serum high-density lipoprotein (HDL) cholesterol have previously been linked to systemic inflammation and neurodegenerative diseases, such as Alzheimer’s disease. Here, we aimed to analyze the lipoprotein profile and inflammatory indicators, the high-sensitivity C-reactive peptide (hs-CRP) and glycoprotein acetyls (GlycA), in sporadic and C9orf72 repeat expansion-associated frontotemporal lobar degeneration (FTLD) patients. The C9orf72 hexanucleotide repeat expansion is the most frequent genetic etiology underlying FTLD. The concentrations of different lipid measures in the sera of 67 FTLD patients (15 C9orf72 repeat expansion carriers), including GlycA, were analyzed by nuclear magnetic resonance spectroscopy. To verify the state of systemic inflammation, hs-CRP was also quantified from patient sera. We found that the total serum HDL concentration was decreased in C9orf72 repeat expansion carriers when compared to non-carriers. Moreover, decreased concentrations of HDL particles of different sizes and subclass were consistently observed. No differences were detected in the very low- and low-density lipoprotein subclasses between the C9orf72 repeat expansion carriers and non-carriers. Furthermore, hs-CRP and GlycA levels did not differ between the C9orf72 repeat expansion carriers and non-carriers. In conclusion, the HDL-related changes were linked with C9orf72 repeat expansion associated FTLD but were not seen to associate with systemic inflammation. The underlying reason for the HDL changes remains unclear.

C9orf72 Repeat Expansion Does Not Affect the Phenotype in Primary Progressive Aphasia

Primary progressive aphasia (PPA) forms the spectrum of language variants of frontotemporal lobar degeneration (FTLD), including three subtypes each consisting of distinctive speech and language features. Repeat expansion in C9orf72 gene is the most common genetic cause of FTLD. However, thus far only little is known about the effects of the C9orf72 repeat expansion on the phenotype of PPA. This retrospective study aimed at determining the differences between the PPA phenotypes of the C9orf72 expansion carriers and non-carriers. Our results demonstrated no significant differences between these groups, indicating that the C9orf72 repeat expansion does not substantially affect the phenotype of PPA.

BV-2 Microglial Cells Overexpressing C9orf72 Hexanucleotide Repeat Expansion Produce DPR Proteins and Show Normal Functionality but No RNA Foci

Hexanucleotide repeat expansion (HRE) in the chromosome 9 open-reading frame 72 (C9orf72) gene is the most common genetic cause underpinning frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). It leads to the accumulation of toxic RNA foci and various dipeptide repeat (DPR) proteins into cells. These C9orf72 HRE-specific hallmarks are abundant in neurons. So far, the role of microglia, the immune cells of the brain, in C9orf72 HRE-associated FTLD/ALS is unclear. In this study, we overexpressed C9orf72 HRE of a pathological length in the BV-2 microglial cell line and used biochemical methods and fluorescence imaging to investigate its effects on their phenotype, viability, and functionality. We found that BV-2 cells expressing the C9orf72 HRE presented strong expression of specific DPR proteins but no sense RNA foci. Transiently increased levels of cytoplasmic TAR DNA-binding protein 43 (TDP-43), slightly altered levels of p62 and lysosome-associated membrane protein (LAMP) 2A, and reduced levels of polyubiquitinylated proteins, but no signs of cell death were detected in HRE overexpressing cells. Overexpression of the C9orf72 HRE did not affect BV-2 cell phagocytic activity or response to an inflammatory stimulus, nor did it shift their RNA profile toward disease-associated microglia. These findings suggest that DPR proteins do not affect microglial cell viability or functionality in BV-2 cells. However, additional studies in other models are required to further elucidate the role of C9orf72 HRE in microglia.

Mutation Analysis of the Genes Linked to Early Onset Alzheimer's Disease and Frontotemporal Lobar Degeneration

A lot of effort has been done to unravel the genetics underlying early-onset Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD). However, many familial early-onset dementia (EOD) cases still show an unclear genetic background. The aim of this study was to evaluate the role of the known causative mutations and possible pathogenic variants associated with AD and FTLD in a Finnish EOD cohort. The cohort consisted of 39 patients (mean age at onset 54.8 years, range 39-65) with a positive family history of dementia or an atypical or rapidly progressive course of the disease. None of the patients carried the C9orf72 hexanucleotide repeat expansion. Mutations and variants in APP, PSEN1, PSEN2, MAPT, GRN, VCP, CHMP2B, FUS, TARDBP, TREM2, TMEM106B, UBQLN2, SOD1, PRNP, UBQLN1, and BIN1 were screened by using a targeted next generation sequencing panel. Two previously reported pathogenic mutations (PSEN1 p.His163Arg and MAPT p.Arg406Trp) were identified in the cohort. Both patients had familial dementia with an atypical early onset phenotype. In addition, a heterozygous p.Arg71Trp mutation in PSEN2 with an uncertain pathogenic nature was identified in a patient with neuropathologically confirmed AD. In conclusion, targeted investigation of the known dementia-linked genes is worthwhile in patients with onset age under 55 and a positive family history, as well as in patients with atypical features.

Diabetes is associated with familial idiopathic normal pressure hydrocephalus: a case-control comparison with family members

BACKGROUND

The pathophysiological basis of idiopathic normal pressure hydrocephalus (iNPH) is still unclear. Previous studies have shown a familial aggregation and a potential heritability when it comes to iNPH. Our aim was to conduct a novel case-controlled comparison between familial iNPH (fNPH) patients and their elderly relatives, involving multiple different families.

METHODS

Questionnaires and phone interviews were used for collecting the data and categorising the iNPH patients into the familial (fNPH) and the sporadic groups. Identical questionnaires were sent to the relatives of the potential fNPH patients. Venous blood samples were collected for genetic studies. The disease histories of the probable fNPH patients (n = 60) were compared with their ≥ 60-year-old relatives with no iNPH (n = 49). A modified Charlson Comorbidity Index (CCI) was used to measure the overall disease burden. Fisher's exact test (two-tailed), the Mann-Whitney U test (two-tailed) and a multivariate binary logistic regression analysis were used to perform the statistical analyses.

RESULTS

Diabetes (32% vs. 14%, p = 0.043), arterial hypertension (65.0% vs. 43%, p = 0.033), cardiac insufficiency (16% vs. 2%, p = 0.020) and depressive symptoms (32% vs. 8%, p = 0.004) were overrepresented among the probable fNPH patients compared to their non-iNPH relatives. In the age-adjusted multivariate logistic regression analysis, diabetes remained independently associated with fNPH (OR = 3.8, 95% CI 1.1-12.9, p = 0.030).

CONCLUSIONS

Diabetes is associated with fNPH and a possible risk factor for fNPH. Diabetes could contribute to the pathogenesis of iNPH/fNPH, which motivates to further prospective and gene-environmental studies to decipher the disease modelling of iNPH/fNPH.

Frontotemporal dementia: a conference report from the 2nd FinFTD Symposium

The 2nd FinFTD Symposium was held on 13 September 2019, in Kuopio, Finland, and attracted 80 attendees from six different countries. The program, spanning from molecular mechanisms to biomarkers, prevention, diagnosis and treatment of frontotemporal lobar degeneration and related diseases, provided a great opportunity for researchers, clinicians, healthcare professionals and other participants to discuss about the current status and future directions of frontotemporal lobar degeneration research.

Serum neurofilament light chain in FTLD: association with C9orf72, clinical phenotype, and prognosis

Objective

The aim of the present study was to compare the levels of serum neurofilament light chain (sNfL) in frontotemporal lobar degeneration (FTLD) patients of different clinical subtypes (bvFTD, PPA, and FTLD‐MND) and with or without the C9orf72 repeat expansion, and to correlate sNfL levels to disease progression, assessed by the brain atrophy rate and survival time.

Methods

The sNfL levels were determined from 78 FTLD patients (C9orf72 repeat expansion carriers [n = 26] and non‐carriers [n = 52]) with Single Molecule Array (SIMOA). The progression of brain atrophy was evaluated using repeated T1‐weighted MRI scans and the survival time from medical records.

Results

In the total FTLD cohort, sNfL levels were significantly higher in C9orf72 repeat expansion carriers compared to non‐carriers. Considering clinical phenotypes, sNfL levels were higher in the C9orf72 repeat expansion carriers than in the non‐carriers in bvFTD and PPA groups. Furthermore, sNfL levels were the highest in the FTLD‐MND group (median 105 pg/mL) and the lowest in the bvFTD group (median 27 pg/mL). Higher sNfL levels significantly correlated with frontal cortical atrophy rate and subcortical grey matter atrophy rate. The higher sNfL levels also associated with shorter survival time.

Interpretation

Our results indicate that the C9orf72 repeat expansion carriers show elevated sNFL levels compared to non‐carriers and that the levels differ among different clinical phenotypes of FTLD. Higher sNfL levels correlated with a shorter survival time and cortical and subcortical atrophy rates. Thus, sNfL could prove as a potential prognostic biomarker in FTLD.

Impact of a Clinical Decision Support Tool on Dementia Diagnostics in Memory Clinics: The PredictND Validation Study

BACKGROUND

Determining the underlying etiology of dementia can be challenging. Computer- based Clinical Decision Support Systems (CDSS) have the potential to provide an objective comparison of data and assist clinicians.

OBJECTIVES

To assess the diagnostic impact of a CDSS, the PredictND tool, for differential diagnosis of dementia in memory clinics.

METHODS

In this prospective multicenter study, we recruited 779 patients with either subjective cognitive decline (n=252), mild cognitive impairment (n=219) or any type of dementia (n=274) and followed them for minimum 12 months. Based on all available patient baseline data (demographics, neuropsychological tests, cerebrospinal fluid biomarkers, and MRI visual and computed ratings), the PredictND tool provides a comprehensive overview and analysis of the data with a likelihood index for five diagnostic groups; Alzheimer´s disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia and subjective cognitive decline. At baseline, a clinician defined an etiological diagnosis and confidence in the diagnosis, first without and subsequently with the PredictND tool. The follow-up diagnosis was used as the reference diagnosis.

RESULTS

In total, 747 patients completed the follow-up visits (53% female, 69±10 years). The etiological diagnosis changed in 13% of all cases when using the PredictND tool, but the diagnostic accuracy did not change significantly. Confidence in the diagnosis, measured by a visual analogue scale (VAS, 0-100%) increased (ΔVAS=3.0%, p<0.0001), especially in correctly changed diagnoses (ΔVAS=7.2%, p=0.0011).

CONCLUSION

Adding the PredictND tool to the diagnostic evaluation affected the diagnosis and increased clinicians' confidence in the diagnosis indicating that CDSSs could aid clinicians in the differential diagnosis of dementia.

Prevalence of Schizophrenia in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a progressive and potentially treatable neurodegenerative disease affecting elderly people, characterized by gait impairment and ventricular enlargement in brain imaging. Similar findings are seen in some patients with schizophrenia (SCZ).

OBJECTIVE

To determine the prevalence of SCZ among patients suffering from probable or possible iNPH and the specific effects of comorbid SCZ on the outcome of the cerebrospinal fluid (CSF) shunting.

METHODS

All medical records of the 521 iNPH patients in the NPH registry were retrospectively analyzed from 1991 until 2017. The prevalence of comorbidity of SCZ was determined and compared to that of general aged (≥65 yr) population in Finland.

RESULTS

We identified a total of 16 (3.1%) iNPH patients suffering from comorbid SCZ. The prevalence of SCZ among the iNPH patients was significantly higher compared to the general population (3.1% vs 0.9%, P < .001). All iNPH patients with comorbid SCZ were CSF shunted and 12 (75%) had a clinically verified shunt response 3 to 12 mo after the procedure. The CSF shunt response rate did not differ between patients with and without comorbid SCZ.

CONCLUSION

SCZ seems to occur 3 times more frequently among iNPH patients compared to the general aged population in Finland. The outcome of the treatment was not affected by comorbid SCZ and therefore iNPH patients suffering from comorbid SCZ should not be left untreated. These results merit validation in other populations. In addition, further research towards the potential connection between these chronic conditions is warranted.

Selection of memory clinic patients for CSF biomarker assessment can be restricted to a quarter of cases by using computerized decision support, without compromising diagnostic accuracy

INTRODUCTION

An accurate and timely diagnosis for Alzheimer's disease (AD) is important, both for care and research. The current diagnostic criteria allow the use of CSF biomarkers to provide pathophysiological support for the diagnosis of AD. How these criteria should be operationalized by clinicians is unclear. Tools that guide in selecting patients in which CSF biomarkers have clinical utility are needed. We evaluated computerized decision support to select patients for CSF biomarker determination.

METHODS

We included 535 subjects (139 controls, 286 Alzheimer's disease dementia, 82 frontotemporal dementia and 28 vascular dementia) from three clinical cohorts. Positive (AD like) and negative (normal) CSF biomarker profiles were simulated to estimate whether knowledge of CSF biomarkers would impact (confidence in) diagnosis. We applied these simulated CSF values and combined them with demographic, neuropsychology and MRI data to initiate CSF testing (computerized decision support approach). We compared proportion of CSF measurements and patients diagnosed with sufficient confidence (probability of correct class ≥0.80) based on an algorithm with scenarios without CSF (only neuropsychology, MRI and APOE), CSF according to the appropriate use criteria (AUC) and CSF for all patients.

RESULTS

The computerized decision support approach recommended CSF testing in 140 (26%) patients, which yielded a diagnosis with sufficient confidence in 379 (71%) of all patients. This approach was more efficient than CSF in none (0% CSF, 308 (58%) diagnosed), CSF selected based on AUC (295 (55%) CSF, 350 (65%) diagnosed) or CSF in all (100% CSF, 348 (65%) diagnosed).

CONCLUSIONS

We used a computerized decision support with simulated CSF results in controls and patients with different types of dementia. This approach can support clinicians in making a balanced decision in ordering additional biomarker testing. Computer-supported prediction restricts CSF testing to only 26% of cases, without compromising diagnostic accuracy.

Cerebrospinal Fluid and MRI Biomarkers in Neurodegenerative Diseases: A Retrospective Memory Clinic-Based Study

BACKGROUND

Cerebrospinal fluid (CSF) and magnetic resonance imaging (MRI) biomarkers of neurodegenerative diseases are relatively sensitive and specific in highly curated research cohorts, but proper validation for clinical use is mostly missing.

OBJECTIVE

We studied these biomarkers in a novel memory clinic cohort with a variety of different neurodegenerative diseases.

METHODS

This study consisted of 191 patients with subjective or objective cognitive impairment who underwent neurological, CSF biomarker (Aβ42, p-tau, and tau) and T1-weighted MRI examinations at Kuopio University Hospital. We assessed CSF and imaging biomarkers, including structural MRI focused on volumetric and cortical thickness analyses, across groups stratified based on different clinical diagnoses, including Alzheimer's disease (AD), frontotemporal dementia, dementia with Lewy bodies, Parkinson's disease, vascular dementia, and mild cognitive impairment (MCI), and subjects with no evidence of neurodegenerative disease underlying the cognitive symptoms. Imaging biomarkers were also studied by profiling subjects according to the novel amyloid, tau, and, neurodegeneration (AT(N)) classification.

RESULTS

Numerous imaging variables differed by clinical diagnosis, including hippocampal, amygdalar and inferior lateral ventricular volumes and entorhinal, lingual, inferior parietal and isthmus cingulate cortical thicknesses, at a false discovery rate (FDR)-corrected threshold for significance (analysis of covariance; p < 0.005). In volumetric comparisons by AT(N) profile, hippocampal volume significantly differed (p < 0.001) between patients with normal AD biomarkers and patients with amyloid pathology.

CONCLUSION

Our analysis suggests that CSF and MRI biomarkers function well also in clinical practice across multiple clinical diagnostic groups in addition to AD, MCI, and cognitively normal groups.

Correction: Whole exome sequencing study identifies novel rare and common Alzheimer's-Associated variants involved in immune response and transcriptional regulation

A correction to this paper has been published and can be accessed via a link at the top of the paper.

Whole exome sequencing study identifies novel rare and common Alzheimer's-Associated variants involved in immune response and transcriptional regulation

The Alzheimer's Disease Sequencing Project (ADSP) undertook whole exome sequencing in 5,740 late-onset Alzheimer disease (AD) cases and 5,096 cognitively normal controls primarily of European ancestry (EA), among whom 218 cases and 177 controls were Caribbean Hispanic (CH). An age-, sex- and APOE based risk score and family history were used to select cases most likely to harbor novel AD risk variants and controls least likely to develop AD by age 85 years. We tested ~1.5 million single nucleotide variants (SNVs) and 50,000 insertion-deletion polymorphisms (indels) for association to AD, using multiple models considering individual variants as well as gene-based tests aggregating rare, predicted functional, and loss of function variants. Sixteen single variants and 19 genes that met criteria for significant or suggestive associations after multiple-testing correction were evaluated for replication in four independent samples; three with whole exome sequencing (2,778 cases, 7,262 controls) and one with genome-wide genotyping imputed to the Haplotype Reference Consortium panel (9,343 cases, 11,527 controls). The top findings in the discovery sample were also followed-up in the ADSP whole-genome sequenced family-based dataset (197 members of 42 EA families and 501 members of 157 CH families). We identified novel and predicted functional genetic variants in genes previously associated with AD. We also detected associations in three novel genes: IGHG3 (p = 9.8 × 10^-7), an immunoglobulin gene whose antibodies interact with β-amyloid, a long non-coding RNA AC099552.4 (p = 1.2 × 10^-7), and a zinc-finger protein ZNF655 (gene-based p = 5.0 × 10^-6). The latter two suggest an important role for transcriptional regulation in AD pathogenesis.

Prevalence of C9ORF72 Expansion in a Large Series of Patients with Idiopathic Normal-Pressure Hydrocephalus

BACKGROUND/AIMS

The C9ORF72 expansion is known to cause frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). We aim to identify the prevalence of the C9ORF72 expansion in idiopathic normal pressure hydrocephalus (iNPH).

METHODS

We analysed the C9ORF72 expansion in a large cohort of patients with possible iNPH (n = 487) and cognitively intact elderly controls (n = 432; age > 65 years).

RESULTS

While the C9ORF72 expansion was detected in 1.6% (n = 8/487) of cases with possible iNPH, no control subject was found to carry the mutation. The mean age at onset of symptoms of C9ORF72 expansion carriers was 59 years (range: 52-67 years), 11 years less than non-carriers (p = 0.0002). The most frequent initial/main symptom pertained to gait difficulties. Despite identified mutation, only 3 of the patients fulfilled the criteria for the FTLD-ALS spectrum. Clinically significant shunt response was detected in 6 out of 7 shunted C9ORF72 expansion carriers.

CONCLUSION

This is the first study cohort identifying the underlying C9ORF72 expansion in patients with iNPH providing evidence for the potential comorbidity between iNPH and the FTLD-ALS spectrum. Analysis of the C9ORF72 expansion should be considered for patients with probable iNPH presenting with frontal atrophy and personality changes or other severe psychiatric symptoms.