Brain magnetic resonance imaging findings six months after critical COVID-19: A prospective cohort study

BACKGROUND

COVID-19 patients suffered from neurological symptoms in the acute phase. Whether this led to long-term consequences was unknown. We studied long-term brain MRI findings in ICU-treated COVID-19 patients and compared them with findings in groups with less severe acute disease.

MATERIALS AND METHODS

In this prospective cohort study, 69 ICU-treated, 46 ward-treated, and 46 home-isolated patients, as well as 53 non-COVID-19 controls, underwent brain MRI six months after acute COVID-19. Plasma neurofilament light chain (NfL), a biomarker of neuroaxonal injury, was measured simultaneously.

RESULTS

Ischaemic infarctions existed in 5.8% of ICU-treated patients. Cerebral microbleeds (CMBs) existed in 27 (39.1%) ICU-treated, 13 (28.3%) ward-treated, 8 (17.4%) home-isolated COVID-19 patients, and 12 (22.6%) non-COVID controls. Patients with CMBs were older (p < 0.001), had a higher level of plasma NfL (p = 0.003), and higher supplementary oxygen days (p < 0.001). In multivariable analysis, age (OR 1.06, 95% CI 1.02-1.09) and supplementary oxygen days (OR 1.07, 95% CI 1.02-1.13) were associated with CMBs. The ICU group showed prevalent distribution of CMBs in deep regions.

CONCLUSION

Age and supplementary oxygen days were independently associated with CMBs; COVID-19 status showed no association. Accumulation of risk factors in the ICU group may explain the higher prevalence of CMBs.

TRIAL REGISTRATION

ClinicalTrials.govNCT04864938, registered February 9, 2021.

Motor difficulties from childhood to midlife: A 40-year cohort study

BACKGROUND

There are few studies of the persistence of childhood motor difficulties (MD) into adulthood.

AIMS

To investigate the association of childhood MD with motor skills and body mass index (BMI) in midlife.

METHODS AND PROCEDURES

We studied 324 adults aged 40 from a cohort born in 1971-1974. At age 9, they had undergone the Test of Motor Impairment, used to classify them into groups: childhood MD (cMD), borderline cMD (bcMD), or no cMD. At age 40, participants comprised 23 with cMD, 47 with bcMD, and 254 with no cMD. Participants completed motor tests of balance, manual dexterity, and visuomotor speed, followed by recording of their BMI.

OUTCOMES AND RESULTS

At age 40, the cMD group performed worse than the no-cMD group on all motor tests (p < .001-.008). The bcMD group had slower visuomotor speed than the no-cMD group (p = .025). The groups differed in BMI (p = .002). Having cMD was associated with obesity in midlife (p < .001). After adjusting for sex, childhood socioeconomic status, and BMI at age 9, both cMD and bcMD were associated with obesity in midlife (p = .015).

CONCLUSIONS AND IMPLICATIONS

Childhood MD are associated with poor motor skills, overweight, and obesity in midlife. This emphasises the importance of early intervention and follow-up when a child exhibits MD.

WHAT THIS PAPER ADDS

This prospective longitudinal study presents novel evidence that individuals with a history of comprehensively and objectively assessed childhood motor difficulties (MD) have worse motor skills and a higher risk of obesity in midlife than do those with no childhood MD. There is a growing literature on adults with developmental coordination disorder or a history of MD. There is, however, a scarcity of longitudinal studies of childhood MD that continue beyond early adulthood, into midlife. In a systematic search, we could identify only one longitudinal study of objectively measured childhood MD with a reassessment of motor skills in those same participants in adulthood, and no study with a reassessment after age 20. Furthermore, longitudinal studies of the association of comprehensively and objectively assessed childhood MD with BMI in midlife have been lacking.

The shared ancestry between the C9orf72 hexanucleotide repeat expansion and intermediate-length alleles using haplotype sharing trees and HAPTK

The C9orf72 hexanucleotide repeat expansion (HRE) is a common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The inheritance is autosomal dominant, but a high proportion of subjects with the mutation are simplex cases. One possible explanation is de novo expansions of unstable intermediate-length alleles (IAs). Using haplotype sharing trees (HSTs) with the haplotype analysis tool kit (HAPTK), we derived majority-based ancestral haplotypes of HRE samples and discovered that IAs containing ≥18-20 repeats share large haplotypes in common with the HRE. Using HSTs of HRE and IA samples, we demonstrate that the longer IA haplotypes are largely indistinguishable from HRE haplotypes and that several ≥18-20 IA haplotypes share over 5 Mb (>600 markers) haplotypes in common with the HRE haplotypes. These analysis tools allow physical understanding of the haplotype blocks shared with the majority-based ancestral haplotype. Our results demonstrate that the haplotypes with longer IAs belong to the same pool of haplotypes as the HRE and suggest that longer IAs represent potential premutation alleles.

Association between relative age at school and persistence of ADHD in prospective studies: an individual participant data meta-analysis

BACKGROUND

The youngest children in a school class are more likely than the oldest to be diagnosed with ADHD, but this relative age effect is less frequent in older than in younger school-grade children. However, no study has explored the association between relative age and the persistence of ADHD diagnosis at older ages. We aimed to quantify the association between relative age and persistence of ADHD at older ages.

METHODS

For this meta-analysis, we searched MEDLINE, Embase, CINAHL, PsycINFO, and PubPsych up to April 1, 2022, with terms related to "cohort" and "ADHD" with no date, publication type, or language restrictions. We gathered individual participant data from prospective cohorts that included at least ten children identified with ADHD before age 10 years. ADHD was defined by either a clinical diagnosis or symptoms exceeding clinical cutoffs. Relative age was recorded as the month of birth in relation to the school-entry cutoff date. Study authors were invited to share raw data or to apply a script to analyse data locally and generate anonymised results. Our outcome was ADHD status at a diagnostic reassessment, conducted at least 4 years after the initial assessment and after age 10 years. No information on sex, gender, or ethnicity was collected. We did a two-stage random-effects individual participant data meta-analysis to assess the association of relative age with persistence of ADHD at follow-up. This study was registered with PROSPERO, CRD42020212650.

FINDINGS

Of 33 119 studies generated by our search, we identified 130 eligible unique studies and were able to gather individual participant data from 57 prospective studies following up 6504 children with ADHD. After exclusion of 16 studies in regions with a flexible school entry system that did not allow confident linkage of birthdate to relative age, the primary analysis included 41 studies in 15 countries following up 4708 children for a period of 4 to 33 years. We found that younger relative age was not statistically significantly associated with ADHD persistence at follow-up (odds ratio 1·02, 95% CI 0·99-1·06; p=0·19). We observed statistically significant heterogeneity in our model (Q=75·82, p=0·0011, I2=45%). Participant-level sensitivity analyses showed similar results in cohorts with a robust relative age effect at baseline and when restricting to cohorts involving children with a clinical diagnosis of ADHD or with a follow-up duration of more than 10 years.

INTERPRETATION

The diagnosis of ADHD in younger children in a class is no more likely to be disconfirmed over time than that of older children in the class. One interpretation is that the relative age effect decreases the likelihood of children of older relative age receiving a diagnosis of ADHD, and another is that assigning a diagnostic label of ADHD leads to unexplored carryover effects of the initial diagnosis that persist over time. Future studies should be conducted to explore these interpretations further.

FUNDING

None.

Health-related quality of life after surviving intensive care for COVID-19: a prospective multicenter cohort study

In survivors of severe coronavirus disease 2019 (COVID-19) incomplete mental and physical recovery may considerably impact daily activities and health-related quality of life (HRQoL). HRQoL can be evaluated with the RAND-36 questionnaire, a multidimensional instrument that assesses physical and mental aspects of health in eight dimensions. The objective was to investigate HRQoL in intensive care patients previously treated for COVID-19 at three Nordic university hospitals, in a prospective multi-center cohort study. HRQoL was measured using RAND-36, 3-9 months after discharge from intensive care units (ICU). One hospital performed a second follow-up 12 months after discharge. A score under the lower limit of the 95% confidence interval in the reference cohorts was considered as significantly reduced HRQoL. We screened 542 and included 252 patients. There was more than twice as many male (174) as female (78) patients and the median age was 61 (interquartile range, IQR 52-69) years. Hypertension was the most common comorbidity observed in 132 (52%) patients and 121 (48%) patients were mechanically ventilated for a median of 8 (IQR 4-14) days. In RAND-36 physical functioning, physical role functioning, general health (p < 0.001 for all) and social functioning (p < 0.05) were below reference, whereas bodily pain, emotional role functioning and mental health were not. In a time-to-event analysis female sex was associated with a decreased chance of reaching the reference HRQoL in the physical function, bodily pain and mental health dimensions. Higher body mass index was found in the physical functioning dimension and hypertension in the physical functioning, vitality and social functioning dimensions. Similar results were seen for diabetes mellitus in general health, vitality and mental health dimensions, as well as pulmonary illness in the physical role functioning dimension and psychiatric diagnosis in the social functioning dimension. Mechanical ventilation was associated with a decreased likelihood of achieving reference HRQoL in the bodily pain and physical functioning dimensions. Patients treated in an ICU because of COVID-19 had lower HRQoL 3-9 months after ICU discharge than 95% of the general population. Physical dimensions were more severely affected than mental dimensions. Female sex and several comorbidities were associated with a slower rate of recovery.Study registration: clinicaltrials.gov: NCT04316884 registered on the 13th of March 2020, NCT04474249 registered on the 29th of June 2020 and NCT04864938 registered on the 4th of April 2021.

C9orf72 hexanucleotide repeat allele tagging SNPs: Associations with ALS risk and longevity

C9orf72 hexanucleotide repeat expansion is a common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The C9orf72 locus may harbor residual risk outside the hexanucleotide repeat expansion, but the evidence is conflicting. Here, we first compared 683 unrelated amyotrophic lateral sclerosis cases and 3,196 controls with Finnish ancestry to find best single nucleotide polymorphisms that tag the C9orf72 hexanucleotide repeat expansion and intermediate-length alleles. Rs2814707 was the best tagging single nucleotide polymorphisms for intermediate-length alleles with ≥7 repeats (p = 5 × 10^-307) and rs139185008 for the hexanucleotide repeat expansion (p = 7 × 10^-114) as well as alleles with ≥20 repeats. rs139185008*C associated with amyotrophic lateral sclerosis after removing cases with the hexanucleotide repeat expansion, especially in the subpopulation homozygous for the rs2814707*T (p = 0.0002, OR = 5.06), which supports the concept of residual amyotrophic lateral sclerosis risk at the C9orf72 haplotypes other than the hexanucleotide repeat expansion. We then leveraged Finnish biobank data to test the effects of rs2814707*T and rs139185008*C on longevity after removing individuals with amyotrophic lateral sclerosis / frontotemporal dementia diagnoses. In the discovery cohort (n = 230,006), the frequency of rs139185008*C heterozygotes decreased significantly with age in the comparisons between 50 and 80 years vs. >80 years (p = 0.0005) and <50 years vs. >80 years (p = 0.0001). The findings were similar but less significant in a smaller replication cohort (2-sided p = 0.037 in 50-80 years vs. >80 years and 0.061 in <50 years vs. >80 years). Analysis of the allele frequencies in 5-year bins demonstrated that the decrease of rs139185008*C started after the age of 70 years. The hexanucleotide repeat expansion tagging single nucleotide polymorphisms decreasing frequency with age suggests its' association with age-related diseases probably also outside amyotrophic lateral sclerosis / frontotemporal dementia.

Long-term cognitive functioning is impaired in ICU-treated COVID-19 patients: a comprehensive controlled neuropsychological study

Background

Cognitive impairment has emerged as a common post-acute sequela of coronavirus disease 2019 (COVID-19). We hypothesised that cognitive impairment exists in patients after COVID-19 and that it is most severe in patients admitted to the intensive care unit (ICU).

Methods

This prospective controlled cohort study of 213 participants performed at the Helsinki University Hospital and the University of Helsinki, Finland, comprised three groups of patients—ICU-treated (n = 72), ward-treated (n = 49), and home-isolated (n = 44)—with confirmed COVID-19 between March 13 and December 31, 2020, participating in a comprehensive neuropsychological evaluation six months after the acute phase. Our study included a control group with no history of COVID-19 (n = 48). Medical and demographic data were collected from electronic patient records and interviews carried out four months after the acute phase. Questionnaires filled six months after the acute phase provided information about change in cognitive functioning observed by a close informant, as well as the presence of self-reported depressive and post-traumatic symptoms.

Results

The groups differed (effect size η²_p = 0.065, p = 0.004) in the total cognitive score, calculated from neuropsychological measures in three domains (attention, executive functions, and memory). Both ICU-treated (p = 0.011) and ward-treated patients (p = 0.005) performed worse than home-isolated patients. Among those with more than 12 years of education, ICU-treated patients performed worse in the attention domain than ward-treated patients (p = 0.021) or non-COVID controls (p = 0.045); ICU-treated male patients, in particular, were impaired in executive functions (p = 0.037).

Conclusions

ICU-treated COVID-19 patients, compared to patients with less severe acute COVID-19 or non-COVID controls, showed more severe long-term cognitive impairment. Among those with more than 12 years of education, impairment existed particularly in the domains of attention and for men, of executive functions.

Trial registration number: ClinicalTrials.gov NCT04864938, retrospectively registered February 9, 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04092-z.

No Clinically Relevant Memory Effects in Perinatal Hyperglycemia and Hypoglycemia: A 40-Year Follow-Up of a Small Cohort

Maternal diabetes mellitus in pregnancy is associated with impairments in memory functions of the offspring in childhood and adolescence but has not been studied in adulthood. The association of perinatal hypoglycemia with memory has not been studied in adulthood either. The combined sequelae of these two risk factors have not been directly compared. We studied general cognitive ability and memory functions in a prospective follow-up of a cohort born in 1971 to 1974. The sample included participants exposed to prenatal hyperglycemia (n = 24), perinatal hypoglycemia (n = 19), or both (n = 7). It also included controls with no early risks (n = 82). We assessed the participants' Intelligence quotient (IQ), working memory, and immediate and delayed recall of both verbal and visual material at the age of 40. We did not find significant differences in IQ or the memory tests between the groups. We did identify an interaction (p = 0.03) of the early risk with the type of digit span task: compared to the controls, the participants exposed to perinatal hypoglycemia had a larger difference between the forward digit span, a measure of attention, and the backward digit span, a measure of working memory processing (p = 0.022). The interaction remained significant when birth weight was controlled for (p = 0.026). Thus, in this small cohort, prenatal hyperglycemia, perinatal hypoglycemia, and their combination appeared relatively benign disorders. The association of these conditions with neurocognitive impairments in adulthood remains unconfirmed. The significance of the working memory difference needs to be verified with a larger sample.

Cognitive Performance at Time of AD Diagnosis: A Clinically Augmented Register-Based Study

We aimed to evaluate the feasibility of using real-world register data for identifying persons with mild Alzheimer’s disease (AD) and to describe their cognitive performance at the time of diagnosis. Patients diagnosed with AD during 2010–2013 (aged 60–81 years) were identified from the Finnish national health registers and enlarged with a smaller private sector sample (total n = 1,268). Patients with other disorders impacting cognition were excluded. Detailed clinical and cognitive screening data (the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological battery [CERAD-nb]) were obtained from local health records. Adequate cognitive data were available for 389 patients with mild AD (31%) of the entire AD group. The main reasons for not including patients in analyses of cognitive performance were AD diagnosis at a moderate/severe stage (n = 266, 21%), AD diagnosis given before full register coverage (n = 152, 12%), and missing CERAD-nb data (n = 139, 11%). The cognitive performance of persons with late-onset AD (n = 284), mixed cerebrovascular disease and AD (n = 51), and other AD subtypes (n = 54) was compared with that of a non-demented sample (n = 1980) from the general population. Compared with the other AD groups, patients with late-onset AD performed the worst in word list recognition, while patients with mixed cerebrovascular disease and AD performed the worst in constructional praxis and clock drawing tests. A combination of national registers and local health records can be used to collect data relevant for cognitive screening; today, the process is laborious, but it could be improved in the future with refined search algorithms and electronic data.

Shortening of Saccades as a Possible Easy-to-Use Biomarker to Detect Risk of Alzheimer's Disease

Background:

Wide-ranging functional defects in eye movements have been reported in Alzheimer’s disease (AD) dementia. The detection of abnormal eye movements and reading problems may identify persons at risk of AD when clear clinical symptoms are lacking.

Objective:

To examine whether computer-based eye-tracking (ET) analysis of King-Devick (KD) test results differentiates cognitively healthy persons from persons with minor problems in cognitive testing or diagnosed mild AD.

Methods:

We recruited 78 participants (57 non-demented, 21 with mild AD) who underwent neurological examination, the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological test battery (CERAD-NB), and a Clinical Dementia Rating (CDR) interview. The non-demented participants were further divided into control (normal CERAD subtests, mean MMSE = 28) and objective mild cognitive impairment (MCI; decline in at least one CERAD memory score, mean MMSE = 27) groups. The KD reading test was performed using computer-based ET. The total time used for the reading test, errors made, fixation and saccade durations, and saccade amplitudes were analyzed.

Results:

We found significant differences between the control, objective MCI, and AD groups in regard to the mean saccade amplitude (3.58, 3.33, and 3.21 ms, respectively, p < 0.03) and duration (27.1, 25.3, and 24.8 ms, respectively, p < 0.05). The KD error scores in the AD group differed significantly (p < 0.01) from the other groups.

Conclusion:

Computed ET analysis of the KD test may help detect persons with objective MCI early when clear clinical symptoms are lacking. The portable device for ET is easy to use in primary health care memory clinics.

Mortality in individuals with childhood ADHD or subthreshold symptoms - a prospective perinatal risk cohort study over 40 years

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is associated with negative life outcomes and recent studies have linked it to increased mortality. These studies have examined nationwide registers or clinic-referred samples and mostly included participants up until the age of 30. No studies have investigated mortality associated with subthreshold levels of ADHD symptoms. Our aim was to analyze mortality in a perinatal risk cohort of 46-year-old adults with childhood ADHD (cADHD) and milder childhood attention problems (including hyperactivity and inattention; cAP) compared with a group with similar birth risks but no or low levels of childhood ADHD symptoms (Non-cAP). Causes of death obtained from a national register were examined.

METHODS

Mortality was analyzed with Cox proportional hazard models for all-cause mortality, cause-specific mortality (natural and unnatural causes), and age-specific mortality (under and over age 30). All models were adjusted with gender. The total n in the study was 839 (cADHD n = 115; cAP n = 216; Non-cAP n = 508).

RESULTS

By the age of 46, 11 (9.6%) deaths occurred in the cADHD group, 7 (3.2%) in the cAP group, and 20 (3.9%) in the Non-cAP group. The cADHD group had the highest mortality risk (adjusted hazard ratio = 2.15; 95% CI 1.02, 4.54). Mortality was not elevated in the cAP group (adjusted hazard ratio = 0.72; 95% CI .30, 1.72). Mortality in the cADHD group was mainly attributed to unnatural causes of death (adjusted hazard ratio = 2.82; 95% CI 1.12, 7.12). The mortality risk in the cADHD group was sixfold before age 30 (adjusted hazard ratio = 6.20; 95% CI 1.78, 21.57).

CONCLUSIONS

Childhood ADHD was associated with a twofold risk of premature death by the age of 46 in this prospective longitudinal cohort study. Our results corroborate previous findings and the morbidity of ADHD. Subthreshold levels of childhood ADHD symptoms were not linked to increased mortality. Our results suggest that mortality risk is higher in young than middle adulthood. Future studies should examine mortality associated with ADHD in different ages in adulthood to identify those in greatest risk of premature death.

Education-Based Cutoffs for Cognitive Screening of Alzheimer's Disease

INTRODUCTION

The educational background and size of the elderly population are undergoing significant changes in Finland during the 2020s. A similar process is likely to occur also in several European countries. For cognitive screening of early Alzheimer's disease (AD), using outdated norms and cutoff scores may negatively affect clinical accuracy. The aim of the present study was to examine the effects of education, age, and gender on the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery (CERAD-nb) in a large register-based, clinical sample of patients with mild AD and nondemented at-risk persons from the general population (controls) and to examine whether corrected cutoff scores would increase the accuracy of differentiation between the 2 groups.

METHODS

CERAD-nb scores were obtained from AD patients (n = 389, 58% women, mean age 74.0 years) and from controls (n = 1,980, 52% women, mean age 68.5 years). The differences in CERAD-nb performance were evaluated by univariate GLM. Differentiation between the 2 groups was evaluated using a receiver operating characteristic (ROC) curve, where a larger area under the ROC curve represents better discrimination. Youden's J was calculated for the overall performance and accuracy of each of the measures.

RESULTS

Of the demographic factors, education was the strongest predictor of CERAD-nb performance, explaining more variation than age or gender in both the AD patients and the controls. Education corrected cutoff scores had better diagnostic accuracy in discriminating between the AD patients and controls than existing uncorrected scores. The highest level of discrimination between the 2 groups overall was found for two CERAD-nb total scores.

CONCLUSIONS

Education-corrected cutoff scores were superior to uncorrected scores in differentiating between controls and AD patients especially for the highest level of education and should therefore be used in clinical cognitive screening, also as the proportion of the educated elderly is increasing substantially during the 2020s. Our results also indicate that total scores of the CERAD-nb are better at discriminating AD patients from controls than any single subtest score. A digital tool for calculating the total scores and comparing education-based cutoffs would increase the efficiency and usability of the test.

Core Competencies in Clinical Neuropsychology as a Training Model in Europe

The multitude of training models and curricula for the specialty of clinical neuropsychology around the world has led to organized activities to develop a framework of core competencies to ensure sufficient expertise among entry-level professionals in the field. The Standing Committee on Clinical Neuropsychology of the European Federation of Psychologists’ Associations is currently working toward developing a specialty certification in clinical neuropsychology to establish a cross-national standard against which to measure levels of equivalency and uniformity in competence and service provision among professionals in the field. Through structured interviews with experts from 28 European countries, we explored potential areas of core competency. Specifically, questions pertained to the perceived importance of a series of foundational, functional, and other competencies, as well as current training standards and practices, and optimal standards. Our findings revealed considerable agreement (about three quarters and above) on academic and clinical training, despite varied actual training requirements currently, with fewer respondents relegating importance to training in teaching, supervision, and research (a little over half), and even fewer to skills related to management, administration, and advocacy (fewer than half). European expert clinical neuropsychologists were in agreement with previous studies (including those conducted in the United States, Australia, and other countries) regarding the importance of sound theoretical and clinical training but management, administrative, and advocacy skills were not central to their perspective of a competent specialist in clinical neuropsychology. Establishing a specialty certificate in clinical neuropsychology based on core competencies may enable mobility of clinical neuropsychologists across Europe, and, perhaps, provide an impetus for countries with limited criteria to reconsider their training requirements and harmonize their standards with others.

Status of Clinical Neuropsychology Training in Finland

This paper provides information on different training models within clinical neuropsychology in Finland. Systematic specialization training program began in Finland in 1983. It was first organized mainly by the Finnish Neuropsychological Society and since 1997 by the Finnish universities. At present, close to 400 clinical neuropsychologists have completed the training. The number of professionals still does not cover the needs of the country (population 5.5 million, area 338,440 km2), and geographical disparities are a constant concern. The training models in Finland have changed over the years and will continue to evolve. Specialization training can be organized by national societies or by universities. It can lead to an academic degree or a diploma. It can be linked to doctoral studies or form a parallel track. Financial model can involve student fees or be governed by ministries (such as the Ministry of Education or Ministry of Health). This paper describes and compares different strategies in education that have impact on the output of professionals. One model does not fit all, or even one country at all times. The strategies of the stakeholder ministries can change over time. The experiences from Finland can be useful for other countries that are developing their models. The estimated need of practitioners and the educational resources including the available financial models for training differ between countries. The guiding principles in specialist training should focus on the advanced competencies expected from the neuropsychologist when entering the profession.

APOE ε4 associates with increased risk of severe COVID-19, cerebral microhaemorrhages and post-COVID mental fatigue: a Finnish biobank, autopsy and clinical study

Apolipoprotein E ε4 allele (APOE4) has been shown to associate with increased susceptibility to SARS-CoV-2 infection and COVID-19 mortality in some previous genetic studies, but information on the role of APOE4 on the underlying pathology and parallel clinical manifestations is scarce. Here we studied the genetic association between APOE and COVID-19 in Finnish biobank, autopsy and prospective clinical cohort datasets. In line with previous work, our data on 2611 cases showed that APOE4 carriership associates with severe COVID-19 in intensive care patients compared with non-infected population controls after matching for age, sex and cardiovascular disease status. Histopathological examination of brain autopsy material of 21 COVID-19 cases provided evidence that perivascular microhaemorrhages are more prevalent in APOE4 carriers. Finally, our analysis of post-COVID fatigue in a prospective clinical cohort of 156 subjects revealed that APOE4 carriership independently associates with higher mental fatigue compared to non-carriers at six months after initial illness. In conclusion, the present data on Finns suggests that APOE4 is a risk factor for severe COVID-19 and post-COVID mental fatigue and provides the first indication that some of this effect could be mediated via increased cerebrovascular damage. Further studies in larger cohorts and animal models are warranted.

DARE to move: feasibility study of a novel dance-based rehabilitation method in severe traumatic brain injury

Objective: Dance is a versatile and multimodal rehabilitation method, which may be useful also in traumatic brain injury (TBI) rehabilitation. Here, we assessed the feasibility and preliminary effects of a novel dance-based intervention called Dual-Assisted Dance Rehabilitation (DARE).Method: This is a feasibility study with a cross-over design where 11 persons with severe/extremely severe TBI received a 12-week (2 times/week) DARE program. Motor and neuropsychological tests and questionnaires measuring mood, executive functions, and quality of life were performed at baseline, 3-month, and 6-month stage. Self-perceived benefits were assessed with a post-intervention questionnaire.Results: Acceptability of and adherence to DARE were encouraging: 91% were fully consistent with protocol, and adherence to DARE sessions was 83-100%. Pre-post treatment effects sizes were medium-large for self-reported depression (BDI-II: d = 1.19-1.74) and executive deficits (BRIEF-A: d = 0.43-1.09) and for test-assessed trunk movement control (TIS: d = 0.47-0.76) and cognitive functioning (WAIS-IV subtests: d = 0.34-0.89). Other outcome measures did not show similar positive effect sizes. Self-perceived benefits were largest for mobility and cognition.Conclusion: Dance-based rehabilitation is a feasible and promising method in severe TBI and its efficacy should be assessed with a larger clinical trial.

Carriership of two copies of C9orf72 hexanucleotide repeat intermediate-length alleles is a risk factor for ALS in the Finnish population

The hexanucleotide repeat expansion in intron 1 of the C9orf72 gene causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. In addition to the effects of the pathogenic expansion, a role of intermediate-length alleles has been suggested in ALS, corticobasal degeneration and Parkinson’s disease. Due to the rarity of intermediate-length alleles with over 20 repeats and the geographical variability in their frequency, large studies that account for population stratification are needed to elucidate their effects. To this aim, we used repeat-primed PCR and confirmatory PCR assays to determine the C9orf72 repeat allele lengths in 705 ALS patients and 3958 controls from Finland. After exclusion of expansion carriers (25.5% of the ALS patients and 0.2% of the controls), we compared the frequency of intermediate-length allele carriers of 525 ALS cases and 3950 controls using several intermediate-length allele thresholds (7–45, 17–45, 21–45, 24–45 and 24–30). The carriership of an intermediate-length allele did not associate with ALS (Fisher’s test, all p ≥ 0.15) nor was there any association with survival (p ≥ 0.33), when we divided our control group into three age groups (18–65, 66–84 and 85–105 years). Carriership of two intermediate-length alleles was associated with ALS, when the longer allele was ≥ 17 repeats (p = 0.002, OR 5.32 95% CI 2.02–14.05) or ≥ 21 repeats (p = 0.00016, OR 15.21 95% CI 3.79–61.0). Our results show that intermediate-length alleles are a risk factor of ALS when present in both alleles, whereas carrying just one intermediate-length allele was not associated with ALS or survival.

Self and Informant Memory Reports in FINGER: Associations with Two-Year Cognitive Change

BACKGROUND

Subjective memory complaints (SMCs) may be the first sign of cognitive decline in aging.

OBJECTIVE

To examine whether SMCs reported by oneself and informant predict cognitive change over 2 years among at-risk elderly people, and to determine the relationship of different types of SMCs (prospective and retrospective memory complaints) and change in cognitive function.

METHODS

This investigation is part of the FINGER project, which is a multicenter randomized controlled trial aiming at preventing cognitive decline in cognitively healthy older adults with increased risk of dementia. A subsample of 303 control-group participants (aged 60-80 years) and their informants (n = 261) rated the frequency of SMCs, using the Prospective and Retrospective Memory Questionnaire (PRMQ). Cognitive performance was measured at baseline and at 1- and 2-year follow-up visits using a neuropsychological test battery.

RESULTS

Participants who reported more SMCs improved less in global cognition, executive function, and memory during the subsequent 2 years in the fully-adjusted analyses. Self-reported retrospective memory problems predicted less improvement in all cognitive domains, whereas prospective memory problems did not. Informant-reported memory problems were not linked to subsequent change in cognition.

CONCLUSION

Our results indicate that self-reported SMCs, measured with PRMQ, predict future cognitive change in several cognitive domains. By contrast, reports by informants were not linked to changes in cognition. Among cognitively healthy at-risk elderly individuals, the persons themselves observe more easily problems relevant for their future cognitive trajectories than their informants.

Clinical Neuropsychology as a Specialist Profession in European Health Care: Developing a Benchmark for Training Standards and Competencies Using the Europsy Model?

The prevalence and negative impact of brain disorders are increasing. Clinical Neuropsychology is a specialty dedicated to understanding brain-behavior relationships, applying such knowledge to the assessment of cognitive, affective, and behavioral functioning associated with brain disorders, and designing and implementing effective treatments. The need for services goes beyond neurological diseases and has increased in areas of neurodevelopmental and psychiatric conditions, among others. In Europe, a great deal of variability exists in the education and training of Clinical Neuropsychologists. Training models include master’s programs, continuing education courses, doctoral programs, and/or post-doctoral specialization depending on the country, with no common framework of requirements, although patients’ needs demand equal competencies across Europe. In the past 5 years, the Standing Committee on Clinical Neuropsychology of the European Federation of Psychologists’ Association has conducted a series of surveys and interviews with experts in the field representing 30 European countries. The information, along with information from the existing literature, is used in presenting an overview of current and relevant topics related to policy and guidelines in the training and competencies in Clinical Neuropsychology. An option for the way forward is the EuroPsy Specialist Certificate, which is currently offered in Work and Organizational Psychology, and in psychotherapy. It builds upon the basic certificate and complements national standards without overriding them. General principles can be found that can set the basis for a common, solid, and comprehensive specialty education/training, sharpening the Neuropsychologists’ competencies across Europe. The requirements in Clinical Neuropsychology should be comparable to those for the existing specialty areas in the EuroPsy model. Despite the perceived challenges, developing a specialist certificate appears a step forward for the development of Clinical Neuropsychology. Recommendations are proposed toward a shared framework of competencies by the means of a common level of education/training for the professionals in Europe. Benchmarking training standards and competencies across Europe has the potential of providing protection against unqualified and ethically questionable practice, creating transparency, raising the general European standard, and promoting mobility of both Clinical Neuropsychologists and patients in Europe, for the benefit of the professional field and the population.

Project DyAdd: Non-linguistic Theories of Dyslexia Predict Intelligence

Two themes have puzzled the research on developmental and learning disorders for decades. First, some of the risk and protective factors behind developmental challenges are suggested to be shared and some are suggested to be specific for a given condition. Second, language-based learning difficulties like dyslexia are suggested to result from or correlate with non-linguistic aspects of information processing as well. In the current study, we investigated how adults with developmental dyslexia or ADHD as well as healthy controls cluster across various dimensions designed to tap the prominent non-linguistic theories of dyslexia. Participants were 18–55-year-old adults with dyslexia (n = 36), ADHD (n = 22), and controls (n = 35). Non-linguistic theories investigated with experimental designs included temporal processing impairment, abnormal cerebellar functioning, procedural learning difficulties, as well as visual processing and attention deficits. Latent profile analysis (LPA) was used to investigate the emerging groups and patterns of results across these experimental designs. LPA suggested three groups: (1) a large group with average performance in the experimental designs, (2) participants predominantly from the clinical groups but with enhanced conditioning learning, and (3) participants predominantly from the dyslexia group with temporal processing as well as visual processing and attention deficits. Despite the presence of these distinct patterns, participants did not cluster very well based on their original status, nor did the LPA groups differ in their dyslexia or ADHD-related neuropsychological profiles. Remarkably, the LPA groups did differ in their intelligence. These results highlight the continuous and overlapping nature of the observed difficulties and support the multiple deficit model of developmental disorders, which suggests shared risk factors for developmental challenges. It also appears that some of the risk factors suggested by the prominent non-linguistic theories of dyslexia relate to the general level of functioning in tests of intelligence.

ADHD and subthreshold symptoms in childhood and life outcomes at 40 years in a prospective birth-risk cohort

We investigated ADHD symptoms and life outcomes in adulthood and their association with childhood ADHD and subthreshold symptoms in a prospectively followed cohort with perinatal risks. We identified participants with childhood ADHD (cADHD, n = 37), subthreshold symptoms defined as attention problems (cAP, n = 64), and no ADHD or cAP (Non-cAP, n = 217). We compared the groups and a control group with no perinatal risks (n = 64) on self-reported ADHD symptoms, executive dysfunction, and life outcomes in adulthood. At age 40, 21.6% of the cADHD, 6.3% of the cAP, 6.0% of the Non-cAP group, and 1.6% of the controls reached a screener cutoff for possible ADHD. The cADHD group had lower educational level, more ADHD symptoms and executive dysfunction, and higher rates of drug use than the other groups. Childhood ADHD associated with perinatal risks persists into midlife whereas childhood subthreshold ADHD symptoms in this cohort were not associated with negative outcomes in adulthood.

Computer-based cognitive training for older adults: Determinants of adherence

The possibilities of computer-based cognitive training (CCT) in postponing the onset of dementia are currently unclear, but promising. Our aim is to investigate older adults´ adherence to a long-term CCT program, and which participant characteristics are associated with adherence to the CCT. This study was part of the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER). Participants were 60-77-year-old individuals with increased dementia risk, recruited from previous population-based studies. The participants included in this study (n = 631) had been randomized to receive a multi-domain lifestyle intervention, including CCT. The measure of adherence was the number of completed CCT sessions (max = 144) as continuous measure. Due to a substantial proportion of participants with 0 sessions, the zero inflated negative binomial regression analyses were used to enable assessment of both predictors of starting the training and predictors of completing a higher number of training sessions. Several cognitive, demographic, lifestyle, and health-related variables were examined as potential predictors of adherence to CCT. Altogether, 63% of the participants participated in the CCT at least once, 20% completed at least half of the training, and 12% completed all sessions. Previous experience with computers, being married or cohabiting, better memory performance, and positive expectations toward the study predicted greater odds for starting CCT. Previous computer use was the only factor associated with a greater number of training sessions completed. Our study shows that there is a large variation in adherence to a long-lasting CCT among older adults with an increased risk of dementia. The results indicate that encouraging computer use, and taking into account the level of cognitive functioning, may help boost adherence to CCT.

Preliminary normative study of ImPACT® in Finnish professional male ice hockey players

Assessment of cognition is an important part of concussion management. The common paradigm of baseline and postinjury evaluations is recommended but due to the often lacking baseline data, reliable normative values are needed. The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®) battery is a widely used method of cognitive assessment offering several language options. There are few comparative studies between language groups on this test battery. ImPACT was administered at baseline to 184 Finnish male Professional Ice Hockey league players. The performance of the Finnish sample differed from previously published English and Czech language samples on the Visual Motor Speed and Reaction Time composites with medium effect-sizes (d = 0.38-0.52). Age, but not education or prior concussions, was associated with ImPACT performance. ImPACT performance is not uniform across language and culture groups and the findings highlight the need for language-specific norms. Finnish reference values for ImPACT for ages <20, 20-26, and >26 are presented. A similar approach is encouraged for other languages.

Training models and status of clinical neuropsychologists in Europe: Results of a survey on 30 countries

OBJECTIVE

The aims of the study were to analyze the current European situation of specialist education and training within clinical neuropsychology, and the legal and professional status of clinical neuropsychologists in different European countries.

METHOD

An online survey was prepared in 2016 by a Task Force established by the European Federation of Psychological Associations, and representatives of 30 countries gave their responses. Response rate was 76%.

RESULTS

Only three countries were reported to regulate the title of clinical neuropsychologist as well as the education and practice of clinical neuropsychologists by law. The most common university degree required to practice clinical neuropsychology was the master's degree; a doctoral degree was required in two countries. The length of the specialist education after the master's degree varied between 12 and 60 months. In one third of the countries, no commonly agreed upon model for specialist education existed. A more systematic training model and a longer duration of training were associated with independence in the work of clinical neuropsychologists.

CONCLUSIONS

As legal regulation is mostly absent and training models differ, those actively practicing clinical neuropsychology in Europe have a very heterogeneous educational background and skill level. There is a need for a European standardization of specialist training in clinical neuropsychology. Guiding principles for establishing the common core requirements are presented.

Language mapping with navigated transcranial magnetic stimulation in pediatric and adult patients undergoing epilepsy surgery: Comparison with extraoperative direct cortical stimulation

Objective

Navigated transcranial magnetic stimulation (nTMS) is becoming increasingly popular in noninvasive preoperative language mapping, as its results correlate well enough with those obtained by direct cortical stimulation (DCS) during awake surgery in adult patients with tumor. Reports in the context of epilepsy surgery or extraoperative DCS in adults are, however, sparse, and validation of nTMS with DCS in children is lacking. Furthermore, little is known about the risk of inducing epileptic seizures with nTMS in pediatric epilepsy patients. We provide the largest validation study to date in an epilepsy surgery population.

Methods

We compared language mapping with nTMS and extraoperative DCS in 20 epilepsy surgery patients (age range 9‐32 years; 14 children and adolescents).

Results

In comparison with DCS, sensitivity of nTMS was 68%, specificity 76%, positive predictive value 27%, and negative predictive value 95%. Age, location of ictal‐onset zone near or within DCS‐mapped language areas or severity of cognitive deficits had no significant effect on these values. None of our patients had seizures during nTMS.

Significance

Our study suggests that nTMS language mapping is clinically useful and safe in epilepsy surgery patients, including school‐aged children and patients with extensive cognitive dysfunction. Similar to in tumor surgery, mapping results in the frontal region are most reliable. False negative findings may be slightly more likely in epilepsy than in tumor surgery patients. Mapping results should always be verified by other methods in individual patients.

Core competencies in clinical neuropsychology training across the world

OBJECTIVE

This work aimed to review main competency requirements from training models in countries with well-established specialties in clinical neuropsychology and to extract core competencies that likely will apply to clinical neuropsychologists regardless of regional and cultural context.

METHOD

We reviewed standards for post-graduate training in clinical neuropsychology from countries in Europe, Australia, and North America based on existing literature, presentations at international conferences, and from description of the training models from national psychological or neuropsychological associations.

RESULTS

Despite differences, the reviewed models share similar core competencies considered necessary for a specialty in clinical neuropsychology: (1) In-depth knowledge of general psychology including clinical psychology (post-graduate level), ethical, and legal standards. (2) Expert knowledge about clinically relevant brain-behavioral relationships. (3) Comprehensive knowledge about, and skills in, related clinical disciplines. (4) In-depth knowledge about and skills in neuropsychological assessment, including decision-making and diagnostic competency according to current classification of diseases. (5) Competencies in the area of diversity and culture in relation to clinical neuropsychology. (6) Communication competency of neuropsychological findings and test results to relevant and diverse audiences. (7) Knowledge about and skills in psychological and neuropsychological intervention, including treatment and rehabilitation.

CONCLUSIONS

All the models have undergone years of development in accordance with requirements of national health care systems in different parts of the world. Despite differences, the common core competency requirements across different regions of the world suggest generalizability of these competencies. We hope this summary can be useful as countries with less established neuropsychology training programs develop their models.

A Prospective 30-Year Follow-Up of ADHD Associated With Perinatal Risks

OBJECTIVE

Longitudinal follow-up of ADHD suggests a poorer outcome in those affected. Studies extending to 30 years however are rare. We investigated the adult outcome of ADHD associated with perinatal risks (PRs), treated non-pharmacologically.

METHOD

A study group of 122 participants (86 men, 36 women) with PR-associated ADHD was followed-up from birth and compared with a control group also prospectively studied.

RESULTS

The study group showed more cognitive, motor perception, and learning impairments as well as psychiatric problems at ages 5, 9, and 16. At age 30, the study group reported less education, more involuntary job dismissals and more alcohol abuse. Self-reported ADHD symptoms were still prevalent in adulthood.

CONCLUSION

ADHD symptoms persist and impair the long-term educational, occupational, and psychiatric outcome. ADHD in participants with PR appears to follow a course seen in studies of unselected ADHD.

Neuropsychology in Finland - over 30 years of systematically trained clinical practice

OBJECTIVE

The aim of this invited paper for a special issue of international practice in The Clinical Neuropsychologist is to provide information on training models, clinical practice, and professional issues within neuropsychology in Finland.

METHOD

Relevant information was gathered via literature searches, a survey by the Neuropsychology Working Group of the Finnish Psychological Association, archives of the Finnish Neuropsychological Society, and personal communication with professionals in Finland.

RESULTS

The roots of Finnish neuropsychology are linked to the early German tradition of experimental psychology. Since the 1970s, it has been strongly influenced by both the psychometric approach in the U.S. and the qualitative approach by Luria. Systematic specialization training program began in Finland in 1983. It was first organized by the Finnish Neuropsychological Society and since 1997 by Finnish universities. At present, around 260 neuropsychologists have completed this training. According to the survey by the Finnish Psychological Association in 2014, 67% of Finnish neuropsychologists work in the public sector, 36% in the private sector, and 28% reported that they had private practice. Work includes assessments for 90% of the respondents, rehabilitation for 74%, and many are involved in teaching and research. Of the respondents, 20% worked both with adults and children, 44% with adults only and 36% with children only. Within test development, pediatric neuropsychology is an especially prominent field.

CONCLUSIONS

A unique blend of approaches and a solid systematic training tradition has led to a strong position of neuropsychologists as distinguished experts in the Finnish health care system.

The PASAT performance among patients with multiple sclerosis: analyses of responding patterns using different scoring methods

The Paced Auditory Serial Addition Test (PASAT) is widely used in the evaluation of multiple sclerosis (MS) patients’ cognitive performance, and also used as the sole measure of cognition in a recently developed assessment tool for MS clinical trials, the Multiple Sclerosis Functional Composite (MSFC). We analysed if MS patients and healthy controls have different patterns of responding in the PASAT, and whether different scoring methods influence the PASAT’s sensitivity and specificity in detecting disease-associated cognitive impairment. Forty-five relapsing-remitting MS patients and 48 healthy controls were evaluated using the PASAT and a comprehensive neuropsychological examination. Cognitively deteriorated MS patients compensated for their difficulties in PASAT by omitting rather than guessing answers. They skipped items intermittently, which reduces the difficulty of the task. Furthermore, towards the end of the PASAT’s 60-item series MS patients’ performance had a trend to fade whereas controls’ performance was more even throughout the task. The dyad score or the percent dyad score did not essentially improve the sensitivity or the specificity, but the accuracy improved when the answers at the end of the PASAT series were specifically emphasized. Using the combined score, 73% of the patients were correctly classified as cognitively impaired or unimpaired.

Adult with Middle Interhemispheric Variant of Holoprosencephaly: Neuropsychological, Clinical, and Radiological Findings

OBJECTIVE

The middle interhemispheric variant of holoprosencephaly (MIHV) is a mild, rare variant of holoprosencephaly. Only a few cases of children with MIHV have been reported. Here we report in detail an adult case.

METHOD

The patient is a female in her 30s. The patient underwent an extensive neuropsychological examination, a neurological examination and a magnetic resonance imaging.

RESULTS

Neuroradiologically, the patient had a typical finding of MIHV, with the absence of the central corpus callosum and union of posterior frontal and anterior parietal gyri. In neuropsychological examination, the patient had average or above average performance in verbal comprehension, naming, reading and writing, and below average performance in perceptual reasoning, visuospatial abilities, processing speed and memory. Also difficulties in mathematical abilities, psychomotor skills, and executive functions were found. No gross neurological involvement was noted. She was diagnosed with atypical depression, post-traumatic stress disorder and a dissociative disorder in early adulthood. Despite cognitive deficits, she was able to achieve a tertiary level education.

CONCLUSIONS

This is the first adult case of MIHV described in detail. Our case emphasizes the possibility of a missed diagnosis of marked brain malformations in patients with craniofacial abnormalities. More cases and prospective follow-up studies are needed to understand the evolvement of both neuropsychological and psychiatric symptoms in these patients.

Teacher Ratings of Executive Function Difficulties in Finnish Children with Combined and Predominantly Inattentive Symptoms of ADHD

School-age children with difficulties in executive functions (EFs) are at risk for substantial academic impairment and poorer developmental outcome. Although Attention Deficit Hyperactivity Disorder (ADHD) is generally associated with weaknesses in EFs, a relatively minimal amount is known about school-related EF difficulties and differences between ADHD subtypes. The present study examined teacher ratings of EF behaviors in 7- to 15-year-old Finnish children with combined symptoms of ADHD (ADHD-C; n = 189), predominantly inattentive symptoms (ADHD-I; n = 25), and no ADHD (n = 691). The teacher ratings showed that both ADHD groups had more EF difficulties than controls. Ratings also indicated specific EF profiles for the ADHD subtypes, students with ADHD-I having more wide-ranging EF difficulties in attention as well as initiation, planning, and execution of actions than children with ADHD-C. According to the present findings, the school-related EF difficulties of children with ADHD-I need to be specifically acknowledged. Teacher ratings seem to be sensitive indicators of EF difficulties and distinguish between different kinds of EF profiles. In clinical practice, rating scales with reliable psychometric properties and normative data relevant to the specific cultural environment should be employed.

Examining methodological variation in response inhibition: The effects of outcome measures and task characteristics on age-related differences

This study addressed methodological issues common to developmental studies on response inhibition. Age-related differences were investigated using two Stroop-like tasks with different levels of complexity and comparing different outcome measures in a sample of 340 children and adolescents aged 7-15 years. First, speed and accuracy of task performance were examined; the results showing that improvement in speed continued until age 13 in both the basic naming task and the two inhibition tasks. Improvement in accuracy was less consistent and continued until age 9 or 13 years. Second, two different algorithms were employed to control for the effects of basic processes in inhibition tasks. The difference algorithm indicated age-related differences similar to those for speed. The ratio algorithm, however, suggested earlier deceleration of development of response inhibition at 9 or 11 years of age. Factors related to the cognitive requirements and presented stimuli also had an effect on the results. The present findings shed light on the inconsistencies in the developmental studies of response inhibition and demonstrated that the selection of outcome measures and task characteristics are critical because they affect the way development is depicted.

Subtle neuropsychiatric and neurocognitive changes in hereditary gelsolin amyloidosis (AGel amyloidosis)

Hereditary gelsolin amyloidosis (AGel amyloidosis) is an autosomal dominant form of systemic amyloidosis caused by a c.640G>A or c.640G>T mutation in the gene coding for gelsolin. Principal clinical manifestations include corneal lattice dystrophy, cranial neuropathy and cutis laxa with vascular fragility. Signs of minor CNS involvement have also been observed, possibly related to cerebral amyloid angiopathy (CAA). To investigate further if AGel amyloidosis carries a risk for a specific neuropsychological or psychiatric symptomatology we studied 35 AGel patients and 29 control subjects. Neuropsychological tests showed abnormalities in visuocontructional and -spatial performance in AGel patients, also some indication of problems in processing efficacy was found. At psychiatric evaluation the patient group showed more psychiatric symptomatology, mainly depression. In brain MRI, available in 16 patients and 14 controls, we found microhemorrhages or microcalcifications only in the patient group, although the number of findings was small. Our study shows that AGel amyloidosis can be associated with visuoconstructional problems and depression, but severe neuropsychiatric involvement is not characteristic. The gelsolin mutation may even induce cerebrovascular fragility, but further epidemiological and histopathological as well as longitudinal follow-up studies are needed to clarify gelsolin-related vascular pathology and its clinical consequences.

Attrition in a 30-year follow-up of a perinatal birth risk cohort: factors change with age

Background. Attrition is a major cause of potential bias in longitudinal studies and clinical trials. Attrition rate above 20% raises concern of the reliability of the results. Few studies have looked at the factors behind attrition in follow-ups spanning decades. Methods. We analyzed attrition and associated factors of a 30-year follow-up cohort of subjects who were born with perinatal risks for neurodevelopmental disorders. Attrition rates were calculated at different stages of follow-up and differences between responders and non-responders were tested. To find combinations of variables influencing attrition and investigate their relative importance at birth, 5, 9, 16 and 30 years of follow-up we used the random forest classification. Results. Initial loss of potential participants was 13%. Attrition was 16% at five, 24% at nine, 35% at 16 and 46% at 30 years. The only group difference that emerged between responders and non-responders was in socioeconomic status (SES). The variables identified by random forest classification analysis were classified into Birth related, Development related and SES related. Variables from all these categories contributed to attrition, but SES related variables were less important than birth and development associated variables. Classification accuracy ranged between 0.74 and 0.96 depending on age. Discussion. Lower SES is linked to attrition in many studies. Our results point to the importance of the growth and development related factors in a longitudinal study. Parents' decisions to participate depend on the characteristics of the child. The same association was also seen when the child, now grown up, decided to participate at 30 years. In addition, birth related medical variables are associated with the attrition still at the age of 30. Our results using a data mining approach suggest that attrition in longitudinal studies is influenced by complex interactions of a multitude of variables, which are not necessarily evident using other multivariate techniques.

Project DyAdd: implicit learning in adult dyslexia and ADHD

In this study of the project DyAdd, implicit learning was investigated through two paradigms in adults (18-55 years) with dyslexia (n = 36) or with attention deficit/hyperactivity disorder (ADHD, n = 22) and in controls (n = 35). In the serial reaction time (SRT) task, there were no group differences in learning. However, those with ADHD exhibited faster RTs compared to other groups. In the artificial grammar learning (AGL) task, the groups did not differ from each other in their learning (i.e., grammaticality accuracy or similarity choices). Further, all three groups were sensitive to fragment overlap between learning and test-phase items (i.e., similarity choices were above chance). Grammaticality performance of control participants was above chance, but that of participants with dyslexia and participants with ADHD failed to differ from chance, indicating impaired grammaticality learning in these groups. While the main indices of AGL performance, grammaticality accuracy and similarity choices did not correlate with the neuropsychological variables that reflected dyslexia-related (phonological processing, reading, spelling, arithmetic) or ADHD-related characteristics (executive functions, attention), or intelligence, the explicit knowledge for the AGL grammar (i.e., ability to freely generate grammatical strings) correlated positively with the variables of phonological processing and reading. Further, SRT reaction times correlated positively with full scale intelligence quotient (FIQ). We conclude that, in AGL, learning difficulties of the underlying rule structure (as measured by grammaticality) are associated with dyslexia and ADHD. However, learning in AGL is not related to the defining neuropsychological features of dyslexia or ADHD. Instead, the resulting explicit knowledge relates to characteristics of dyslexia.

Adult neurobehavioral outcome of hyperbilirubinemia in full term neonates-a 30 year prospective follow-up study

Background. Neonatal hyperbilirubinemia (HB) may cause severe neurological damage, but serious consequences are effectively controlled by phototherapy and blood exchange transfusion. HB is still a serious health problem in economically compromised parts of the world. The long term outcome has been regarded favorable based on epidemiological data, but has not been confirmed in prospective follow-up studies extending to adulthood.

Methods. We studied the long term consequences of HB in a prospective birth cohort of 128 HB cases and 82 controls. The cases are part of a neonatal at-risk cohort (n = 1196) that has been followed up to 30 years of age. HB cases were newborns ≥ 2500 g birth weight and ≥ 37 weeks of gestation who had bilirubin concentrations > 340 µmol/l or required blood exchange transfusion. Subjects with HB were divided into subgroups based on the presence (affected HB) or absence (unaffected HB) of diagnosed neurobehavioral disorders in childhood, and compared with healthy controls. Subjects were seen at discharge, 5, 9 and 16 years of life and parent’s and teacher’s assessments were recorded. At 30 years they filled a questionnaire about academic and occupational achievement, life satisfaction, somatic and psychiatric symptoms including a ADHD self-rating score. Cognitive functioning was tested using ITPA, WISC, and reading and writing tests at 9 years of life.

Results. Compared to controls, the odds for a child with HB having neurobehavioral symptoms at 9 years was elevated (OR = 4.68). Forty-five per cent of the HB group were affected by cognitive abnormalities in childhood and continued to experience problems in adulthood. This was apparent in academic achievement (p < 0.0001) and the ability to complete secondary (p < 0.0001) and tertiary (p < 0.004) education. Also, the subgroup of affected HB reported persisting cognitive complaints e.g., problems with reading, writing and mathematics. Childhood symptoms of hyperactivity/impulsivity (p < 0.0001) and inattention (p < 0.02) were more common in HB groups, but in adulthood the symptoms were equal. The affected HB had lower scores in parameters reflecting life satisfaction, less controlled drinking, but not increased substance abuse.

Discussion. Our results indicate that neonatal HB has negative consequences in adult age. A prospectively collected cohort with strict inclusion criteria enables to control most of the bias factors involved with retrospective data. The control and HB groups were remarkably similar at birth in terms of medical data, and the growth environment of the children, as well as the parents’ social groups, education, size of family, type of housing at birth and at 9 years of age. Our findings bear resemblance to disorders of the fronto-striatal network, and also symptoms of the ADHD spectrum were frequent in the HB group suggesting a link of HB to other neurodevelopmental disorders.

The Perinatal Adverse events and Special Trends in Cognitive Trajectory (PLASTICITY) - pre-protocol for a prospective longitudinal follow-up cohort study

Prospective follow-up studies on long term effects of pre- and perinatal adverse conditions in adulthood are rare. We will continue to follow the prospective cohort of initially 1196 subjects with predefined at-delivery risk factors out of 22,359 consecutive deliveries during 1971-74 at a single maternity hospital. The risk cohort and 93 controls have been followed up with a comprehensive clinical program at 5, 9, and 16 years of age and by questionnaire at the age of 30 years. Major medical events known to affect the development and growth of the brain, or cognitive functions and personality have been documented. Here we present a pre-protocol for the project, which we will call PLASTICITY, whose aim is to follow consenting subjects and controls into mid-adulthood and beyond, and to explore how the neonatal risk factors modulate neurodevelopmental and neurodegenerative processes such as learning disabilities, ADHD, aging, early onset mild cognitive impairment and even dementia. Our first focus is on the neurological and cognitive outcomes at age 40 years, using detailed neurological, neuropsychological, neuroimaging, genetic, blood chemistry and registry based methods. Results will be expected to offer information on the risk of neurological, psychiatric, metabolic and other medical consequences as well as the need for health and social services at the brink of middle age, when new degenerative phenomena are known to emerge. The evaluation at age 40 years will serve as a baseline for later aging studies. We welcome all comments and suggestions, which we will apply in finalizing details and inviting collaboration.