The Study of Language in the Amyotrophic Lateral Sclerosis - Frontotemporal Spectrum Disorder: a Systematic Review of Findings and New Perspectives

Verbal expressive language minimally affected in non-demented people living with amyotrophic lateral sclerosis

Objective: Language dysfunction is one of the most common cognitive impairments in amyotrophic lateral sclerosis (ALS). Although discourse capacities are essential for daily functioning, verbal expressive language has not been widely investigated in ALS. The existing research available suggests that discourse impairments are prevalent. This study investigates verbal expressive language in people living with ALS (plwALS) in contrast to healthy controls (HC).Methods: 64 plwALS and 49 age, gender and education-matched healthy controls were ask to describe the Cookie Theft Picture Task. The recordings were analyzed for discourse productivity, discourse content, syntactic complexity, speech fluency and verb processing. We applied the Bayesian hypothesis-testing framework, incorporating the effects of dysarthria, cognitive impairment status (CIS), and premorbid crystalline verbal IQ.Results: Compared to HC, plwALS only showed a single impairment: speech dysfluency. Discourse productivity, discourse content, syntactic complexity and verb processing were not impaired. Cognition and dysarthria exceeded the influence of verbal IQ for total words spoken and content density. Cognition alone seemed to explain dysfluency. Body-agent verbs were produced at even higher rates than other verb types. For the remaining outcomes, verbal IQ was the most decisive factor.Conclusions: In contrast to existing research, our data demonstrates no discernible impairment in verbal expressive language in ALS. What our findings show to be decisive is accounting for the influence of dysarthria, cognitive impairment status, and verbal IQ as variables on spontaneous verbal expressive language. Minor impairments in verbal expressive language appear to be influenced to a greater degree by executive dysfunctioning and dysarthria than by language impairment.

Frontotemporal-spectrum disorders and functional independence in non-demented ALS patients

BACKGROUND

The present study aimed at determining whether, net of motor confounders, neuropsychological features affect functional independence (FI) in activities of daily living (ADLs) in non-demented amyotrophic lateral sclerosis (ALS) patients.

METHODS

N = 88 ALS patients without frontotemporal dementia were assessed for FI-Katz's Basic ADL Scale (BADL) and Lawton-Brody's Instrumental ADL Scale (IADL)-, cognition-Edinburgh Cognitive and Behavioural ALS Screen (ECAS)-and behaviour-Beaumont Behavioural Inventory and Dimensional Apathy Scale. The association between cognitive and behavioural measures and BADL/IADL scores was assessed by covarying for demographics, anxiety and depression levels, disease duration and motor confounders-i.e. ALS Functional Rating Scale-Revised (ALSFRS-R) scores, progression rate and both King's and Milano-Torino stages.

RESULTS

Higher scores on the ECAS-Language were associated with higher IADL scores (p = 0.005), whilst higher apathetic features-as measured by the Dimensional Apathy Scale (DAS)-were inversely related to the BADL (p = 0.003). Whilst IADL scores were related to all ECAS-Language tasks, the DAS-Initiation was the only subscale associated with BADL scores. Patients with abnormal ECAS-Language (p = 0.023) and DAS (p = 0.008) scores were more functionally dependent than those without.

DISCUSSION

Among non-motor features, language changes and apathetic features detrimentally affect FI in non-demented ALS patients.

Assessment of Language Function in Older Mandarin-Speaking Adults with Mild Cognitive Impairment using Multifaceted Language Tests

BACKGROUND

Individuals with amnestic mild cognitive impairment (aMCI), especially for those with multidomain cognitive deficits, should be clinically examined for determining risk of developing Alzheimer's disease. English-speakers with aMCI exhibit language impairments mostly at the lexical-semantic level. Given that the language processing of Mandarin Chinese is different from that of alphabetic languages, whether previous findings for English-speakers with aMCI can be generalized to Mandarin Chinese speakers with aMCI remains unclear.

OBJECTIVE

This study examined the multifaceted language functions of Mandarin Chinese speakers with aMCI and compared them with those without cognitive impairment by using a newly developed language test battery.

METHODS

Twenty-three individuals with aMCI and 29 individuals without cognitive impairment were recruited. The new language test battery comprises five language domains (oral production, auditory and reading comprehension, reading aloud, repetition, and writing).

RESULTS

Compared with the controls, the individuals with aMCI exhibited poorer performance in the oral production and auditory and reading comprehension domains, especially on tests involving effortful lexical and semantic processing. Moreover, the aMCI group made more semantic naming errors compared with their counterparts and tended to experience difficulty in processing items belonging to the categories of living objects.

CONCLUSIONS

The pattern identified in the present study is similar to that of English-speaking individuals with aMCI across multiple language domains. Incorporating language tests involving lexical and semantic processing into clinical practice is essential and can help identify early language dysfunction in Mandarin Chinese speakers with aMCI.

Bulbar involvement and cognitive features in amyotrophic lateral sclerosis: a retrospective study on 347 patients

Background

This study aimed at clarifying the role of bulbar involvement (BI) as a risk factor for cognitive impairment (CI) in non-demented amyotrophic lateral sclerosis (ALS) patients.

Methods

Data on N = 347 patients were retrospectively collected. Cognition was assessed via the Edinburgh Cognitive and Behavioral ALS Screen (ECAS). On the basis of clinical records and ALS Functional Rating Scale-Revised (ALSFRS-R) scores, BI was characterized as follows: (1) BI at onset-from medical history; (2) BI at testing (an ALSFRS-R-Bulbar score ≤11); (3) dysarthria (a score ≤3 on item 1 of the ALSFRS-R); (4) severity of BI (the total score on the ALSFRS-R-Bulbar); and (5) progression rate of BI (computed as 12-ALSFRS-R-Bulbar/disease duration in months). Logistic regressions were run to predict a below- vs. above-cutoff performance on each ECAS measure based on BI-related features while accounting for sex, disease duration, severity and progression rate of respiratory and spinal involvement and ECAS response modality.

Results

No predictors yielded significance either on the ECAS-Total and -ALS-non-specific or on ECAS-Language/-Fluency or -Visuospatial subscales. BI at testing predicted a higher probability of an abnormal performance on the ECAS-ALS-specific (p = 0.035) and ECAS-Executive Functioning (p = 0.018). Lower ALSFRS-R-Bulbar scores were associated with a defective performance on the ECAS-Memory (p = 0.025). No other BI-related features affected other ECAS performances.

Discussion

In ALS, the occurrence of BI itself, while neither its specific features nor its presence at onset, might selectively represent a risk factor for executive impairment, whilst its severity might be associated with memory deficits.

Prevalence and determinants of language impairment in non-demented amyotrophic lateral sclerosis patients

BACKGROUND AND PURPOSE

This study aimed at estimating the prevalence of language impairment (LI) in a large, clinic-based cohort of non-demented amyotrophic lateral sclerosis (ALS) patients and assessing its underpinnings at motor and non-motor levels.

METHODS

Non-demented ALS patients (N = 348) underwent the Edinburgh Cognitive and Behavioural ALS Screen (ECAS), as well as an assessment of behavioural/psychiatric and motor-functional features. The prevalence of LI was estimated based on the proportion of patients showing a performance below the age- and education-adjusted cut-off on the ECAS-Language. Multiple regression models were run to assess the determinants of language functioning and impairment.

RESULTS

The prevalence of LI was 22.7%. 46.6% of the variance of ECAS-Language scores remained unexplained, with only the ECAS-Executive positively predicting them (p < 0.001; η²  = 0.07). Similarly, only a lower score on the ECAS-Executive predicted a higher probability of a below cut-off ECAS-Language performance (p < 0.001). Spelling and Naming tasks were the major drivers of ECAS-Language performance.

CONCLUSIONS

This study suggests that, in non-demented ALS patients, LI occurs in ≈23% of cases, is significantly driven by executive dysfunction but, at the same time, partially independent of it and is not associated with other motor or non-motor features.

Convenient Auditory-Based Language and Executive Function Test for Patients With Amyotrophic Lateral Sclerosis: A Pilot Study

OBJECTIVE

About 30%-50% of patients with amyotrophic lateral sclerosis (ALS) show cognitive impairment ranging from mild dysexecutive syndrome to frontotemporal dementia. We aimed to develop a brief cognitive test, convenient auditory-based language and executive function test (CABLET), for rapid detection of cognitive impairment in ALS, with reduced load on motor function.

METHOD

The CABLET comprises two tests using auditory verbal stimuli: Test 1, assessing word repetition and lexical judgment, and Test 2, evaluating verbal short-term memory and semantics knowledge. The administration time of Test 1 and Test 2 was 1 and 3-5 min, respectively. Overall, 61 patients with ALS and 46 age-, sex-, and education-matched healthy controls participated in this study. All participants underwent existing neuropsychological tests and the CABLET. We investigated the applicability of the CABLET to detect ALS with cognitive impairment (ALSci) from normal cognition.

RESULTS

Receiver operating characteristic analyses showed that both the CABLET total and Test 2 had good diagnostic accuracy (area under the curve [AUC]: total = 0.894, Test 2 = 0.893). Test 2 had the highest sensitivity (100% sensitivity and 71.4% specificity). No significant difference existed in the AUC between the analyses with and without age, education, and disease severity as covariates. Correlations were observed between the CABLET and established neuropsychological tests, supporting its good convergent validity.

CONCLUSIONS

Our findings indicated that the CABLET could be useful in identifying ALSci quickly without adjusting for confounding factors. Further validation is required to evaluate it in larger groups and compare with ALS-specific cognitive screen.

Cognition and motor phenotypes in ALS: a retrospective study

Background

Amyotrophic lateral sclerosis (ALS) is phenotypically heterogeneous in motor manifestations, and the extent of upper vs. lower motor neuron involvement is a widespread descriptor. This study aimed to examine cognition across different ALS motor phenotypes.

Methods

ALS patients (N = 124) were classified as classical (N = 66), bulbar (N = 13), predominant-upper motor neuron (PUMN; N = 19), and predominant-lower motor neuron (PLMN; N = 26) phenotypes. Cognition was assessed with the Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and function with the ALS Functional Rating Scale—Revised (ALSFRS-R). Revised ALS-FTD consensus criteria were applied for cognitive/behavioral phenotyping.

Results

Defective ECAS-total scores were detected in all groups — bulbar: 15.4%, classical: 30.3%, PLMN: 23.1%, and PUMN: 36.8%. Classical and PUMN ALS patients performed worse than PLMN ones on ECAS-total, ALS-specific, Fluency, and Executive measures. No other difference was detected. Worse ASLFRS-R scores correlated with poorer ECAS-total scores in classical ALS patients.

Conclusions

Frontotemporal cognitive deficits are more prevalent in PUMN and classical ALS and linked to disease severity in the latter, but occur also in PLMN phenotypes.

Supplementary information

The online version contains supplementary material available at 10.1007/s10072-022-06157-x

Identifying key signs of motor neurone disease in primary care: a nested case-control study using the QResearch database

OBJECTIVE

To confirm the symptoms and signs for motor neuron disease (MND) in the Red Flag tool; to quantify the extent to which the key symptoms and signs are associated with MND; and to identify additional factors which may be helpful within the primary care setting in recognition of possible MND and triggering timely referral to neurology specialists.

DESIGN

A nested case-control study.

SETTING

1292 UK general practices contributing to the QResearch primary care database, linked to hospital and mortality data.

PARTICIPANTS

Baseline cohort included 16.8 million individuals aged 18 years and over without a diagnosis of MND at study entry and with more than 3 years of digitalised information available. The nested case-control data set comprised of 6437 cases of MND diagnosed between January 1998 and December 2019, matched by year of birth, gender, general practice and calendar year to 62 003 controls.

MAIN OUTCOME MEASURES

Clinically recognised symptoms and signs of MND prior to diagnosis and symptoms and factors which are relevant in primary care setting.

RESULTS

This study identified 17 signs and symptoms that were independently associated with MND diagnosis in a multivariable analysis. Of these, seven were new to the Red Flag tool: ataxia, dysphasia, weight loss, wheeze, hoarseness of voice, urinary incontinence and constipation. Among those from the Red Flag tool, dysarthria had the strongest association with subsequent MND (adjusted OR (aOR): 43.2 (95% CI 36.0 to 52.0)) followed by muscle fasciculations (aOR: 40.2 (95% CI 25.6 to 63.1)) and muscle wasting (aOR: 31.0 (95% CI 19.5 to 49.4)). Additionally, the associations between MND diagnosis and family history, dropped foot, focal weakness and sialorrhoea remained robust after controlling for confounders. Patients who reported symptoms indicative of damage to the lower brainstem and its connections were diagnosed sooner than those who presented with respiratory or cognitive signs.

CONCLUSION

This is the first study that has identified, confirmed and quantified the association of key symptoms and signs with MND diagnosis. In addition to known factors, the study has identified the following new factors to be independently associated with MND prior to diagnosis: ataxia, dysphasia, wheeze and hoarseness of voice. These findings may be used to improve risk stratification and earlier detection of MND in primary care.

A verb-naming test accurately detects cognitive changes in ALS

Verb-naming tests were proposed for detecting cognitive impairment in ALS, although statistical evidence on their clinical usefulness is still lacking. A total of 29 ALS patients and 29 demographic-matched healthy controls (HCs) were administered the Action-Verb-Naming Test (AVNT), a standardized picture-naming task of actions. Patients were also administered the Edinburgh Cognitive and Behavioral ALS Screen (ECAS), and classified according to Strong et al. (Amyotrophic lateral sclerosis-frontotemporal spectrum disorder (ALS-FTSD): revised diagnostic criteria. Amyotroph Lateral Scler Frontotemporal Degener. 2017;18:153-4) criteria. The AVNT discriminated ALS patients from HCs (p = 0.026) and yielded high accuracy in detecting cognitive impairments among ALS patients (88% of accuracy; sensitivity = 1; specificity = 0.84; PPV = 0.5; NPV = 1; LR+ = 3.83; LR- = 0), as well as a below-cutoff performance on the ECAS (AUC = 0.74). The AVNT was unrelated to other clinical variables, despite being strongly associated with ECAS total, ALS-specific, Language and Executive scores (r_s = 0.65-0.75). These findings show that verb naming is an accurate test to detect domain-specific cognitive changes in ALS patients, regardless of their disease phenotype.

The diagnostic value of the Italian version of the Edinburgh Cognitive and Behavioral ALS Screen (ECAS)

Objectives: The diagnostic capabilities of specific cognitive screeners are clinically crucial for an early detection of frontotemporal features in amyotrophic lateral sclerosis (ALS) patients. This study aimed at providing diagnostic properties of the cognitive section of the Edinburgh Cognitive and Behavioral ALS Screen (ECAS) in Italian ALS patients.Methods: Eighty-nine consecutive Italian ALS patients were classified according to Strong et al. (2017) criteria with a comprehensive neuropsychological assessment. The Italian version of ECAS was also administered, and its accuracy, sensitivity (SE), specificity (SP), negative and positive predictive values (PPV; NPV) and likelihood ratios (LR+; LR-) were computed against clinical diagnoses.Results: The ECAS and its subscales yielded moderate-to-high accuracy (AUC = .7-.87). High SP was overall found (81.8%-100%). The most sensitive measures were ALS-specific and Executive (73.9-78.3%) subscales, while the least were the ALS-non-specific subscales (8.7-17.4%). ECAS measures showed good PPVs (60%-100%) and NPVs (75.9%-91.5%). Acceptable LRs were found (LR+: 6.97-4.3; LR-: .29-.91), with total and ALS-specific measures yielding the best estimates.Conclusions: This is the first study demonstrating the diagnostic value of the ECAS against a thorough neuropsychological assessment in Italy. ECAS-total and -ALS-specific scores are diagnostically sound as to both intrinsic and post-test features, whereas ALS-non-specific measures perform slightly worse.

Pathophysiological Underpinnings of Extra-Motor Neurodegeneration in Amyotrophic Lateral Sclerosis: New Insights From Biomarker Studies

Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) lie at opposing ends of a clinical, genetic, and neuropathological continuum. In the last decade, it has become clear that cognitive and behavioral changes in patients with ALS are more frequent than previously recognized. Significantly, these non-motor features can impact the diagnosis, prognosis, and management of ALS. Partially overlapping neuropathological staging systems have been proposed to describe the distribution of TAR DNA-binding protein 43 (TDP-43) aggregates outside the corticospinal tract. However, the relationship between TDP-43 inclusions and neurodegeneration is not absolute and other pathophysiological processes, such as neuroinflammation (with a prominent role of microglia), cortical hyperexcitability, and synaptic dysfunction also play a central role in ALS pathophysiology. In the last decade, imaging and biofluid biomarker studies have revealed important insights into the pathophysiological underpinnings of extra-motor neurodegeneration in the ALS-FTLD continuum. In this review, we first summarize the clinical and pathophysiological correlates of extra-motor neurodegeneration in ALS. Next, we discuss the diagnostic and prognostic value of biomarkers in ALS and their potential to characterize extra-motor neurodegeneration. Finally, we debate about how biomarkers could improve the diagnosis and classification of ALS. Emerging imaging biomarkers of extra-motor neurodegeneration that enable the monitoring of disease progression are particularly promising. In addition, a growing arsenal of biofluid biomarkers linked to neurodegeneration and neuroinflammation are improving the diagnostic accuracy and identification of patients with a faster progression rate. The development and validation of biomarkers that detect the pathological aggregates of TDP-43 in vivo are notably expected to further elucidate the pathophysiological underpinnings of extra-motor neurodegeneration in ALS. Novel biomarkers tracking the different aspects of ALS pathophysiology are paving the way to precision medicine approaches in the ALS-FTLD continuum. These are essential steps to improve the diagnosis and staging of ALS and the design of clinical trials testing novel disease-modifying treatments.

Cognitive and behavioral involvement in ALS has been known for more than a century

BACKGROUND

Among clinicians and researchers, it is common knowledge that, in ALS, cognitive and behavioral involvement within the spectrum of frontotemporal degenerations (FTDs) begun to be regarded as a fact in the late 1990s of the twentieth century. By contrast, a considerable body of evidence on cognitive/behavioral changes in ALS can be traced in the literature dating from the late nineteenth century.

METHODS

Worldwide reports on cognitive/behavioral involvement in ALS dating from 1886 to 1981 were retrieved thanks to Biblioteca di Area Medica "Adolfo Ferrate," Sistema Bibliotecario di Ateneo, University of Pavia, Pavia, Italy and qualitatively synthetized.

RESULTS

One-hundred and seventy-four cases of ALS with co-occurring FTD-like cognitive/behavioral changes, described in Europe, America, and Asia, were detected. Neuropsychological phenotypes were consistent with the revised Strong et al.'s consensus criteria. Clinical observations were not infrequently supported by histopathological, post-mortem verifications of extra-motor, cortical/sub-cortical alterations, as well as by in vivo instrumental exams-i.e., assessments of brain morphology/physiology and psychometric testing. In this regard, as earlier as 1907, the notion of motor and cognitive/behavioral features in ALS yielding from the same underlying pathology was acknowledged. Hereditary occurrences of ALS with cognitive/behavioral dysfunctions were reported, as well as familial associations with ALS-unrelated brain disorders. Neuropsychological symptoms often occurred before motor ones. Bulbar involvement was at times acknowledged as a risk factor for cognitive/behavioral changes in ALS.

DISCUSSION

Historical observations herewith delivered can be regarded as the antecedents of current knowledge on cognitive/behavioral impairment in the ALS-FTD spectrum.

Patterns of Language Impairment in Early Amyotrophic Lateral Sclerosis

Objective

To investigate the incidence and nature of language change and its relationship to executive dysfunction in a population-based incident amyotrophic lateral sclerosis (ALS) sample, with the hypothesis that patterns of frontotemporal involvement in early ALS extend beyond areas of executive control to regions associated with language processing.

Methods

One hundred seventeen population-based incident ALS cases without dementia and 100 controls matched by age, sex, and education were included in the study. A detailed assessment of language processing including lexical processing, word spelling, word reading, word naming, semantic processing, and syntactic/grammatical processing was undertaken. Executive domains of phonemic verbal fluency, working memory, problem-solving, cognitive flexibility, and social cognition were also evaluated.

Results

Language processing was impaired in this incident cohort of individuals with ALS, with deficits in the domains of word naming, orthographic processing, and syntactic/grammatical processing. Conversely, phonological lexical processing and semantic processing were spared. Although executive dysfunction accounted in part for impairments in grammatical and orthographic lexical processing, word spelling, reading, and naming, primary language deficits were also present.

Conclusions

Language impairment is characteristic of ALS at early stages of the disease and can develop independently of executive dysfunction, reflecting selective patterns of frontotemporal involvement at disease onset. Language change is therefore an important component of the frontotemporal syndrome associated with ALS.

Speech and language impairments in behavioral variant frontotemporal dementia: A systematic review

Although behavioral variant frontotemporal dementia (bvFTD) is classically defined by behavioral and socio-emotional changes, impairments often extend to other cognitive functions. These include early speech and language deficits related to the disease's core neural disruptions. Yet, their scope and clinical relevance remains poorly understood. This systematic review characterizes such disturbances in bvFTD, considering clinically, neuroanatomically, genetically, and neuropathologically defined subgroups. We included 181 experimental studies, with at least 5 bvFTD patients diagnosed using accepted criteria, comparing speech and language outcomes between bvFTD patients and healthy controls or between bvFTD subgroups. Results reveal extensive and heterogeneous deficits across cohorts, with (a) consistent lexico-semantic, reading & writing, and prosodic impairments; (b) inconsistent deficits in motor speech and grammar; and (c) relative preservation of phonological skills. Also, preliminary findings suggest that the severity of speech and language deficits might be associated with global cognitive impairment, predominantly temporal or fronto-temporal atrophy and MAPT mutations (vs C9orf72). Although under-recognized, these impairments contribute to patient characterization and phenotyping, while potentially informing diagnosis and management.

Evaluation and categorisation of individual patients based on white matter profiles: Single-patient diffusion data interpretation in neurodegeneration

The majority of radiology studies in neurodegenerative conditions infer group-level imaging traits from group comparisons. While this strategy is helpful to define phenotype-specific imaging signatures for academic use, the meaningful interpretation of single scans of individual subjects is more important in everyday clinical practice. Accordingly, we present a computational method to evaluate individual subject diffusion tensor data to highlight white matter integrity alterations. Fifty white matter tracts were quantitatively evaluated in 132 patients with amyotrophic lateral sclerosis (ALS) with respect to normative values from 100 healthy subjects. Fractional anisotropy and radial diffusivity alterations were assessed individually in each patient. The approach was validated against standard tract-based spatial statistics and further scrutinised by the assessment of 78 additional data sets with a blinded diagnosis. Our z-score-based approach readily detected white matter degeneration in individual ALS patients and helped to categorise single subjects with a 'blinded diagnosis' as likely 'ALS' or 'control'. The group-level inferences from the z-score-based approach were analogous to the standard TBSS output maps. The benefit of the z-score-based strategy is that it enables the interpretation of single DTI datasets as well as the comparison of study groups. Outputs can be summarised either visually by highlighting the affected tracts, or, listing the affected tracts in a text file with reference to normative data, making it particularly useful for clinical applications. While individual diffusion data cannot be visually appraised, our approach provides a viable framework for single-subject imaging data interpretation.

Pathophysiology and Treatment of Non-motor Dysfunction in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive and fatal neurodegenerative disease typically presenting with bulbar or limb weakness. There is increasing evidence that amyotrophic lateral sclerosis is a multisystem disease with early and frequent impacts on cognition, behaviour, sleep, pain and fatigue. Dysfunction of normal physiological and metabolic processes also appears common. Evidence from pre-symptomatic studies and large epidemiological cohorts examining risk factors for the future development of amyotrophic lateral sclerosis have reported a high prevalence of changes in behaviour and mental health before the emergence of motor weakness. This suggests that changes beyond the motor system are underway at an early stage with dysfunction across brain networks regulating a variety of cognitive, behavioural and other homeostatic processes. The full impact of non-motor dysfunction continues to be established but there is now sufficient evidence that the presence of non-motor symptoms impacts overall survival in amyotrophic lateral sclerosis, and with up to 80% reporting non-motor symptoms, there is an urgent need to develop more robust therapeutic approaches. This review provides a contemporary overview of the pathobiology of non-motor dysfunction, offering readers a practical approach with regard to assessment and management. We review the current evidence for pharmacological and non-pharmacological treatment of non-motor dysfunction in amyotrophic lateral sclerosis and highlight the need to further integrate non-motor dysfunction as an important outcome measure for future clinical trial design.

Cognitive dysfunction in amyotrophic lateral sclerosis: can we predict it?

Background and aim

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the degeneration of both upper and lower motoneurons in the brain and spinal cord leading to motor and extra-motor symptoms. Although traditionally considered a pure motor disease, recent evidences suggest that ALS is a multisystem disorder. Neuropsychological alterations, in fact, are observed in more than 50% of patients: while executive dysfunctions have been firstly identified, alterations in verbal fluency, behavior, and pragmatic and social cognition have also been described. Detecting and monitoring ALS cognitive and behavioral impairment even at early disease stages is likely to have staging and prognostic implications, and it may impact the enrollment in future clinical trials. During the last 10 years, humoral, radiological, neurophysiological, and genetic biomarkers have been reported in ALS, and some of them seem to potentially correlate to cognitive and behavioral impairment of patients. In this review, we sought to give an up-to-date state of the art of neuropsychological alterations in ALS: we will describe tests used to detect cognitive and behavioral impairment, and we will focus on promising non-invasive biomarkers to detect pre-clinical cognitive decline.

Conclusions

To date, the research on humoral, radiological, neurophysiological, and genetic correlates of neuropsychological alterations is at the early stage, and no conclusive longitudinal data have been published. Further and longitudinal studies on easily accessible and quantifiable biomarkers are needed to clarify the time course and the evolution of cognitive and behavioral impairments of ALS patients.

Cognitive reserve and regional brain volume in amyotrophic lateral sclerosis

OBJECTIVE

We investigated whether cognitive reserve measured by education and premorbid IQ allows amyotrophic lateral sclerosis patients to compensate for regional brain volume loss.

METHODS

This was a cross-sectional study. We recruited sixty patients with amyotrophic lateral sclerosis from two specialist out-patient clinics. All participants underwent neuropsychological assessment; the outcomes were standardized z-scores reflecting verbal fluency, executive functions (shifting, planning, working memory), verbal memory and visuo-constructive ability. The predictor was regional brain volume. The moderating proxies of cognitive reserve were premorbid IQ (estimated by vocabulary) and educational years. We hypothesized that higher cognitive reserve would correlate with better performance on a cognitive test battery, and tested this hypothesis with Bayesian analysis of covariance.

RESULTS

The analyses provided moderate to very strong evidence in favor of our hypothesis with regard to verbal fluency functions, working memory, verbal learning and recognition, and visuo-constructive ability (all BF₀₁ > 3): higher cognitive reserve was associated with a mild increase in performance. For shifting and planning ability, the evidence was anecdotal.

CONCLUSIONS

These results indicate that cognitive reserve moderates the effect of brain morphology on cognition in ALS. Patients draw small but meaningful benefits from higher reserve, preserving fluency, memory and visuo-constructive functions. Executive functions presented a dissociation: verbally assessed functions benefitted from cognitive reserve, non-verbally assessed functions did not. This motivates future research into cognitive reserve in ALS and practical implications, such as strengthening reserve to delay decline.

Cognitive network hyperactivation and motor cortex decline correlate with ALS prognosis

We aimed to quantitatively characterize progressive brain network disruption in Amyotrophic Lateral Sclerosis (ALS) during cognition using the mismatch negativity (MMN), an electrophysiological index of attention switching. We measured the MMN using 128-channel EEG longitudinally (2-5 timepoints) in 60 ALS patients and cross-sectionally in 62 healthy controls. Using dipole fitting and linearly constrained minimum variance beamforming we investigated cortical source activity changes over time. In ALS, the inferior frontal gyri (IFG) show significantly lower baseline activity compared to controls. The right IFG and both superior temporal gyri (STG) become progressively hyperactive longitudinally. By contrast, the left motor and dorsolateral prefrontal cortices are initially hyperactive, declining progressively. Baseline motor hyperactivity correlates with cognitive disinhibition, and lower baseline IFG activities correlate with motor decline rate, while left dorsolateral prefrontal activity predicted cognitive and behavioural impairment. Shorter survival correlates with reduced baseline IFG and STG activity and later STG hyperactivation. Source-resolved EEG facilitates quantitative characterization of symptom-associated and symptom-preceding motor and cognitive-behavioral cortical network decline in ALS.

Dysfunction of the left angular gyrus may be associated with writing errors in ALS

Background: Language dysfunction is a feature of cognitive impairment in amyotrophic lateral sclerosis (ALS) that may compromise communication. Objective: To elucidate language dysfunction in patients with ALS and its relationship with other neuropsychological tests and to identify the brain regions associated with this dysfunction using perfusion image. Methods: Overall, 37 patients with ALS were included in this study. Their neuropsychological function was investigated using the Western Aphasia Battery (WAB), Frontal Assessment Battery and Behavioral Assessment of the Dysexecutive Syndrome. N-isopropyl-p-[¹²³I] iodoamphetamine single-photon emission computed tomography was used to examine regional cerebral blood flow and its relationship with WAB scores was investigated using multiple regression analyses, controlled for age, sex and years of education. Results: Frequency of language abnormality in ALS was 8.5% for spontaneous speech, 25.7% for auditory verbal comprehension, 8.8% for repetition, 14.7% for naming, 17.6% for reading and 51.4% for writing. The writing error was mainly omission and substitution of kana letters. Executive tests were correlated with naming (r > 0.5, p < 0.001) and reading (r > 0.4, p < 0.01) scores. With respect to the writing sub-test, positive perfusional relationship was only detected in the left angular gyrus. Conclusions: The left angular gyrus is the region associated with the writing errors observed in ALS.

The spectrum of language impairments in amyotrophic lateral sclerosis

Language disorders are increasingly recognised in Amyotrophic lateral sclerosis (ALS), supporting the view of ALS as a multi-system disorder, impacting cognitive and motor function. However, the language impairments are heterogeneous and recent focus has been on determining the language profile across the ALS spectrum with little focus on spontaneous speech. The current study systematically investigated a wide range of language abilities in an unselected ALS sample (N = 22), including spontaneous speech. We analysed the ALS patients' performance as a group, compared to age-, education- and IQ-matched healthy controls (N = 21), and as a case series to identify dementia and specific language profiles. The ALS group was impaired on measures of spontaneous speech, word fluency and action naming. By contrast, object naming, semantic memory (object and actions), sentence comprehension and repetition (word and sentences) were comparable to healthy controls. In line with recent suggestions, our ALS patients' action naming (but not action semantic) deficit does not support the notion that action processing may be selectively impaired in ALS. The case series demonstrated that 14% of patients had probable dementia, 31% showed significant cognitive and/or language impairment and 55% were unimpaired, consistent with the spectrum of cognitive and language impairments reported in the literature. In addition, 36% of ALS patients produced significantly fewer words per minute on a spontaneous speech task than the control group, with this difference remaining when the ALS patients with frontotemporal dementia were excluded from the analysis. This pattern was observed across the ALS spectrum and in both limb and bulbar onset patients. The pattern of performance observed in the present study suggests that spontaneous speech is reduced across the ALS spectrum even in those with intact core language abilities.

Cognitive and behavioural impairment in amyotrophic lateral sclerosis

PURPOSE OF REVIEW

The current review provides an up to date overview of the nature and progression of the cognitive and behavioural impairment in amyotrophic lateral sclerosis (ALS). Understanding these symptoms has implications for the management of the disease and the design of clinical trials, in addition to the support of patient and caregiver regarding mental capacity and end of life decision-making.

RECENT FINDINGS

Cognitive and behavioural change in ALS are best characterized as the consequence of extensive network dysfunction. 35-45% of ALS patients present with mild-moderate cognitive impairment and comorbid dementia occurs in approximately 14% of patients, the majority of these meeting diagnostic criteria for frontotemporal dementia (FTD). Cognitive change in ALS manifests most commonly as executive dysfunction and language impairment. Behavioural change in the form of apathy, disinhibition, loss of sympathy and empathy, stereotyped behaviours and dietary changes occur.

SUMMARY

Cognitive and behavioural impairment is an important feature of ALS, and reflects broad network dysfunction of frontostriatal and frontotemporal systems. Cognition and behaviour should be assessed early in the diagnostic process, and data driven approaches should be developed to enable reliable quantitative outcome assessment suitable for clinical trials.

Validating a functional near-infrared spectroscopy diagnostic paradigm for Major Depressive Disorder

Reduced haemodynamic response in the frontotemporal cortices of patients with major depressive disorder (MDD) has been demonstrated using functional near-infrared spectroscopy (fNIRS). Most notably, changes in cortical oxy-haemoglobin during a Japanese phonetic fluency task can differentiate psychiatric patients from healthy controls (HC). However, this paradigm has not been validated in the English language. Therefore, the present work aimed to distinguish patients with MDD from HCs, using haemodynamic response measured during an English letter fluency task. One hundred and five HCs and 105 patients with MDD took part in this study. NIRS signals during the verbal fluency task (VFT) was acquired using a 52-channel system, and changes in oxy-haemoglobin in the frontal and temporal regions were quantified. Depression severity, psychosocial functioning, pharmacotherapy and psychiatric history were noted. Patients with MDD had smaller changes in oxy-haemoglobin in the frontal and temporal cortices than HCs. In both regions of interest, oxy-haemoglobin was not associated with any of the clinical variables studied. 75.2% and 76.5% of patients with MDD were correctly classified using frontal and temporal region oxy-haemoglobin, respectively. Haemodynamic response measured by fNIRS during an English letter fluency task is a promising biomarker for MDD.

The reading the mind in the eyes test short form (A & B): validation and outcomes in an amyotrophic lateral sclerosis cohort

Objective: Deficits in social cognition are part of the cognitive phenotype of amyotrophic lateral sclerosis (ALS). This study investigated the psychometric properties and test-retest reliability of two short-form versions of the Reading the Mind in the Eyes Test. Method: Patients with ALS (n = 50), alongside age and IQ matched controls (n = 50) were recruited. The Reading the Mind in the Eyes Test (RMET) was apportioned according to previously published psychometric properties yielding two short forms. The internal consistency, test-retest reliability, item difficulty, and discrimination coefficient were computed to determine the utility of the short forms. Two one-sided t-test (TOST) assessed equivalency, and a ROC curve analysis determined a cutoff for impairment. Results: Cronbach's Alpha > 0.7 was observed for the RMET Short Form A and RMET Short Form B, indicating adequate internal consistency. Both RMET Short Forms had excellent psychometric properties when discriminating between ALS patients who performed well, compared to those who did not, with an overall medium difficulty coefficient observed. The TOST found the short forms to be equivalent. Conclusion: Social cognition is an important cognitive construct in ALS, as is its measurement. This study contributes not only to the psychometric knowledge of this measure, but also to the usability, efficacy, reliability, and repeatability of two short forms.

Speech network regional involvement in bulbar ALS: a multimodal structural MRI study

Objective: To examine gray (GM) and white matter (WM) structural changes in regions of the speech network (SpN) in ALS patients with varying degree of bulbar disease. Methods: T1 and DTI images were obtained for 19 ALS participants and 13 neurologically-intact controls. Surface-based, volumetric, and DTI metrics were obtained for 6 regions-of-interest (ROIs) including the primary motor cortex (PMC), pars triangularis (parsT), pars opercularis (ParsO), posterior superior temporal gyrus (pSTG), and transverse temporal (TT). Disease-effects and brain-behavioral correlates between neuroanatomy and clinical measures of bulbar, limb, and overall disability were examined using linear models. Results: Structural changes were observed in the right oral and limb PMC and left ParsT, TT, and pSTG in ALS. Bulbar motor dysfunction was associated with WM abnormalities in the right oral PMC and left pSTG, and GM changes in bilateral TT. In contrast, symptom progression rate predicted GM and WM changes in bilateral pars opercularis (part of Broca's area). Grip strength and disease duration models were non-significant. Conclusions: The findings suggested that regions of the left-dominant SpN may be implicated in ALS and degeneration of these areas are related to bulbar disease severity. Involvement of regions that overlap across multiple connectomes such as Broca's area, however, may be dependent on the rate of disease progression. The work contributes to our understanding of bulbar ALS subtype, which is crucial for predicting disease progression, delivering targeted clinical care, and appropriate recruitment into clinical trials.

Primary progressive aphasia and the FTD-MND spectrum disorders: clinical, pathological, and neuroimaging correlates

Objective: Behavioral variant frontotemporal dementia (bvFTD), is commonly considered the cognitive presentation of the frontotemporal dementia-motor neuron disease (FTD-MND) spectrum disorder. We evaluated the prevalence of primary progressive aphasia in a series of pathologically confirmed cases of FTD-MND spectrum. Methods: Pathologically confirmed cases of frontotemporal lobar degeneration-motor neuron disease (FTLD-MND) were obtained from the UCSF brain bank. Cases were analyzed for presence of language impairment via retrospective chart review of research visits that include neurologic exam, in-depth cognitive testing and magnetic resonance imaging (MRI) imaging. Forty one cases were included. Thirty two were diagnosed with FTD-MND, while nine cases were diagnosed as MND-only from clinical evaluation. Results: Ten FTLD-MND cases (31%) presented with prominent or isolated language involvement consistent with a diagnosis of primary progressive aphasia (PPA), which we called progressive aphasia with motor neuron disease (PA-MND). Of these, three cases that mirrored the non-fluent variant of PPA (nfvPPA) were named nfvPA-MND. The imaging pattern of these nfvPA-MND showed atrophy strictly confined to the frontal and anterior temporal language cortical areas. Another group of seven cases that resembled patients with the semantic variant PPA (svPPA) were named svPA-MND. The group of svPPA-MND on imaging analysis showed selective atrophy of the temporal lobe and orbitofrontal cortex. Conclusions: Language impairment was a frequent phenotype of FTD-MND associated with focal atrophy patterns within the language networks. This data suggest patients with FTD-MND can present quite often with language phenotype of nfvPPA and svPPA, as opposed to exclusive bvFTD symptoms.

Clinical and Radiological Markers of Extra-Motor Deficits in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is now universally recognized as a complex multisystem disorder with considerable extra-motor involvement. The neuropsychological manifestations of frontotemporal, parietal, and basal ganglia involvement in ALS have important implications for compliance with assistive devices, survival, participation in clinical trials, caregiver burden, and the management of individual care needs. Recent advances in neuroimaging have been instrumental in characterizing the biological substrate of heterogeneous cognitive and behavioral deficits in ALS. In this review we discuss the clinical and radiological aspects of cognitive and behavioral impairment in ALS focusing on the recognition, assessment, and monitoring of these symptoms.

Unimpaired Neuropsychological Performance and Enhanced Memory Recall in Patients with Sbma: A Large Sample Comparative Study

Peculiar cognitive profile of patients with SBMA has been described by fragmented literature. Our retrospective study reports the neuropsychological evaluations of a large cohort of patients in order to contribute towards the understanding of this field. We consider 64 neuropsychological evaluations assessing mnesic, linguistic and executive functions collected from 2013 to 2015 in patients attending at Motor Neuron Disease Centre of University of Padova. The battery consisted in: Digit Span forwards and backwards, Prose Memory test, Phonemic Verbal fluency and Trail making tests. ANCOVA statistics were employed to compare tests scores results with those obtained from a sample of healthy control subjects. Multiple linear regressions were used to study the effect on cognitive performance of CAG-repeat expansion, the degree of androgen insensitivity and their interaction to cognitive performance. Statistical analyses did not reveal altered scores in any neuropsychological tests among those adopted. Interestingly, patients performed significantly better in the Prose Memory test's score. No relevant associations were found with genetic, hormonal or clinical patients' profile. Results inconsistent with previous studies have been interpreted according to the phenomenon of somatic mosaicism. We suggest a testosterone-related and the mood state-dependant perspectives as two possible interpretations of the enhanced performances in the Prose Memory test. Further studies employing more datailed tests batteries are encouraged.