iPSC-derived cortical neurons to study sporadic Alzheimer disease: A transcriptome comparison with post-mortem brain samples

Alzheimer's disease (AD) is the most common cause of dementia, characterized by the progressive impairment of cognition and memory loss. Sporadic AD (sAD) represents approximately 95 % of the AD cases and is induced by a complex interplay between genetic and environmental factors called "Alzheimerogens". Heavy metals (e.g. copper) and pesticides (e.g. fipronil) can affect many AD-related processes, including neuroinflammation (considered as AD-inducing factor). Research would benefit from in vitro models to investigate effects of Alzheimerogens. We compared transcriptomics changes in sAD induced pluripotent stem cell (iPSC) derived cortical neurons to differentially expressed genes (DEGs) identified in post-mortem AD brain tissue. These analyses showed that many AD-related processes could be identified in the sAD iPSC-derived neurons, and furthermore, could even identify more DEGs functioning in these processes than post-mortem AD-brain tissue. Thereafter, we exposed the iPSCs to AD-inducing factors (copper(II)chloride, fipronil sulfone and an inflammatory cytokine cocktail). Cytokine exposure induced expression of immune related genes while copper-exposure affected genes involved in lipid and cholesterol metabolism, which are known AD-related processes. Fipronil-exposure did not result in significant transcriptomic changes, although prolonged exposures or higher doses may be necessary. Overall, we show that iPSC-derived cortical neurons can be beneficial in vitro models to identify Alzheimerogens and AD-related molecular mechanisms.

Procarboxypeptidase U (proCPU, TAFI, proCPB2) in cerebrospinal fluid during ischemic stroke is associated with stroke progression, outcome and blood-brain barrier dysfunction

Essentials Little is known of procarboxypeptidase U (proCPU) in cerebrospinal fluid (CSF) of stroke patients. ProCPU levels were studied in CSF of controls and non-thrombolyzed acute ischemic stroke patients. ProCPU is elevated in CSF of stroke patients compared with controls. ProCPU in CSF correlates with stroke progression, outcome, and blood-brain barrier dysfunction.

SUMMARY

Background Procarboxypeptidase U (proCPU, TAFI, proCPB2), the zymogen of CPU, which is a potent antifibrinolytic enzyme and a modulator of inflammation, has previously been investigated in plasma of stroke patients, but so far, no information on the proCPU levels in cerebrospinal fluid (CSF) during acute ischemic stroke (AIS) is available. Objectives This case-control observational study investigates proCPU in CSF of AIS patients compared with controls with an intact blood-brain barrier (BBB) and evaluates the relationship of CSF/plasma proCPU ratios with stroke parameters. Methods A sensitive HPLC-based enzymatic assay was used to determine proCPU levels in CSF of non-thrombolyzed patients in the hyperacute phase (< 24 h after onset) of AIS (n = 72). Individuals (n = 32) without stroke, an intact BBB and no apparent abnormalities in biochemical and microbiological tests, served as controls. Relations between the CSF/plasma proCPU ratio and (i) stroke severity, (ii) stroke progression/recurrence, (iii) stroke outcome and (iv) BBB dysfunction (CSF/serum albumin ratio) were assessed. Results Mean (SEM) proCPU levels were elevated in the CSF of stroke patients compared with controls (4.36 (0.23) U L-1 vs. 3.50 (0.23) U L-1 ). Higher median [IQR] CSF/plasma proCPU ratios were found in patients with stroke progression ((6.0 [4.2-6.9]) × 10-3 ) and poor outcome ((6.4 [3.9-7.0]) × 10-3 ) after 3 months (modified Rankin Scale; mRS > 3) compared with patients without progression ((3.9 [2.7-5.4]) × 10-3 ) or better outcome ((4.0 [2.8-5.0]) × 10-3 ). In stroke patients with a disrupted BBB, proCPU ratios were higher compared with stroke patients with an intact BBB ((6.4 [5.8-9.0]) × 10-3 vs. (3.7 [2.8-5.0]) × 10-3 ). Conclusions ProCPU is increased in CSF during hyperacute ischemic stroke and is associated with stroke progression and outcome after 3 months, most likely due to BBB dysfunction in the hyperacute phase of ischemic stroke.

[Detection and prevention in later life: risk profiles for physical, psychological, social and environmental frailty.]

In order to provide proactive care and support for older people attention is needed for the prevention of frailty among older adults. Subsequently, accurate case finding of those who are more at risk of becoming frail is crucial to undertake specific preventive actions. This study investigates frailty and risk profiles of frailty among older people in order to support proactive detection. Hereby, frailty is conceived not only as a physical problem, but also refers to emotional, social, and environmental hazards. Using data generated from the Belgian Ageing Studies (N = 21,664 home-dwelling older people), a multinomial logistic regression model was tested which included socio-demographic and socio-economic indicators as well as the four dimensions of frailty (physical, social, psychological and environmental). Findings indicate that for both men and women having moved in the previous 10 years and having a lower household income are risk factors of becoming multidimensional frail. However, studying the different frailty domains, several risk profiles arise (e. g. marital status is important for psychological frailty), and gender-specific risk groups are detected (e. g. non-married men). This paper elaborates on practical implications and formulates a number of future research recommendations to tackle frailty in an ageing society.

Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

We identified rare coding variants associated with Alzheimer's disease in a three-stage case-control study of 85,133 subjects. In stage 1, we genotyped 34,174 samples using a whole-exome microarray. In stage 2, we tested associated variants (P < 1 × 10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, we used an additional 14,997 samples to test the most significant stage 2 associations (P < 5 × 10-8) using imputed genotypes. We observed three new genome-wide significant nonsynonymous variants associated with Alzheimer's disease: a protective variant in PLCG2 (rs72824905: p.Pro522Arg, P = 5.38 × 10-10, odds ratio (OR) = 0.68, minor allele frequency (MAF)cases = 0.0059, MAFcontrols = 0.0093), a risk variant in ABI3 (rs616338: p.Ser209Phe, P = 4.56 × 10-10, OR = 1.43, MAFcases = 0.011, MAFcontrols = 0.008), and a new genome-wide significant variant in TREM2 (rs143332484: p.Arg62His, P = 1.55 × 10-14, OR = 1.67, MAFcases = 0.0143, MAFcontrols = 0.0089), a known susceptibility gene for Alzheimer's disease. These protein-altering changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified risk genes in Alzheimer's disease. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to the development of Alzheimer's disease.

Biochemical markers in vascular cognitive impairment associated with subcortical small vessel disease - A consensus report

Background

Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data.

Method

The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized.

Results

This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer’s disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood–brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau.

Conclusions

Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.

SolCos model-based individual reminiscence for older adults with mild to moderate dementia in nursing homes: a randomized controlled intervention study

WHAT IS KNOWN ON THE SUBJECT?: To stimulate reminiscence of older adults with dementia performed individually or through group sessions is a well-known practice in nursing homes resulting in effects on behaviour and well-being as an alternative for medication. Robust scientific proof of the effectiveness of individual reminiscence therapy performed in nursing homes is sparse. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: We have provided individual standardized reminiscence therapy to residents with dementia. The therapy was developed and tested in a previous study and performed in this study by trained nursing home volunteers. In comparison with a control group who received usual care, residents who received the reminiscence therapy showed significant less depressive symptoms. Moreover, residents were, in general, attentive, open and collaborative during the sessions and volunteers experienced the sessions as useful and pleasant. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Individual reminiscence therapy can be learned and used by nursing home volunteers to improve care in nursing homes.

ABSTRACT

Aim To investigate the effect of a standardized individualized intervention based on the SolCos transformational reminiscence model on depressive symptoms (primary outcome), cognition and behaviour (secondary outcomes) for older people with mild to moderate dementia, performed by trained nursing home volunteers as facilitators. Background Because of limited pharmacological treatment options for older adults with dementia relevant physical, sensory, psychological or social interventions offer alternative opportunities. Method Randomized controlled trial (ISRCTN74355073) was set up in two nursing homes with 29 and 31 residents in the intervention and the control groups respectively. Eighteen nursing home volunteers were trained to perform the reminiscence therapy. Various assessment scales were measured pre- and post-sessions. Results Linear regression analysis showed an impact on depressive symptoms. However, no impact was identified on cognition and behaviour. Facilitators experienced the sessions as useful and pleasant, and study participants were, in general, attentive, open and collaborative. Discussion Study results showed that organizing standardized individual reminiscence therapy with nursing home volunteers was feasible and study participants' attention and participation were overall good. Further study initiatives to explore the potential of individual reminiscence therapy within a person-centred framework are recommended in order to improve care in nursing homes.

Poststroke depression and its multifactorial nature: results from a prospective longitudinal study

OBJECTIVE

Poststroke depression (PSD) is commonly observed in stroke patients and has a negative impact on functional outcome and quality of life. Therefore, a prospective, longitudinal epidemiological study was conducted aiming to determine prevalence and risk factors for PSD at 1, 3, 6, 12 and 18 months poststroke.

METHODS

A total of 222 patients were included in the study and 201 patients entered data analysis. Demographic data, vascular risk factors, stroke characteristics, functional and neurocognitive outcome measures and psychosocial factors were considered as potential risk factors for PSD. Clinically significant signs and symptoms of PSD were quantified by means of the Cornell Scale for Depression (CSD) and the Montgomery and Åsberg Depression Rating Scale (MADRS).

RESULTS

PSD was present at 1, 3, 6, 12 and 18 months poststroke in 24.5%, 27.1%, 28.3%, 19.8% and 26.3% of the patients respectively. Univariate regression analyses revealed that PSD was significantly associated with stroke severity, physical disability, cognitive impairment and stroke outcome during the 18 months time frame of the study. Reduced social activities and the presence of apraxia were consistently associated with PSD whereas aphasia was only significantly associated in the first 6 months after stroke. Patients with relational problems had a 3 times greater risk of becoming depressed at 18 months poststroke than patients without relational problems (OR=3.09; 95% CI=1.31-7.26).

CONCLUSIONS

Risk factors for PSD seem variable indicating the need for clinicians to consider the dynamic and multifactorial nature of PSD emphasizing the importance of a rigorous and long-term monitoring and support of stroke patients and their caregivers.

Psychosocial problems associated with depression at 18 months poststroke

OBJECTIVE

With a prevalence that varies between 20% and 65%, poststroke depression (PSD) is a frequent sequel of stroke. The aim of this study was to determine incidence and risk factors for PSD 18 months after stroke.

METHODS

As part of the Middelheim Interdisciplinary Stroke Study, patients were followed up for 18 months in this prospective and longitudinal epidemiological study. Clinically significant signs and symptoms of PSD were quantified by means of the Cornell Scale for Depression (CSD) and the Montgomery and Åsberg Depression Rating Scale. Activities, including social activities, were measured with the Stroke Impact Scale (SIS). Relational problems since stroke onset were defined by a questionnaire.

RESULTS

Data analysis was performed on 125 patients who completed follow-up assessments. Depression (CSD score ≥8) was diagnosed in 28% of the patients. Patients with PSD were more dependent for activities of daily living and displayed more physical and cognitive impairment than patients without PSD. The risk to become depressed decreased with 5% when the patient's activities increased with one unit on the SIS (odds ratio (OR) = 0.95; 95% confidence interval (CI) = 0.93-0.97). Patients with persistent relational problems since stroke onset had approximately four and a half times greater risk of becoming depressed than patients without (OR = 4.48; 95%CI = 1.17-16.87).

CONCLUSIONS

Multiple regression models indicated that the most determining features for developing PSD at 18 months poststroke include reduced activity and relationship problems due to stroke. Further studies on risk factors for PSD are essential, including psychosocial aspects, given its negative impact on rehabilitation and quality of life.

Rationale and clinical data supporting nutritional intervention in Alzheimer's disease

Adequate nutrition plays an important role in the maintenance of cognitive function, particularly during aging. Malnutrition is amongst the risk factors for developing mild cognitive impairment (MCI) and Alzheimer's disease (AD). Epidemiological studies have associated deficiencies in some nutrients with a higher risk of cognitive dysfunction and/or AD. Cognitive decline in AD is correlated with synaptic loss and many of the components required to maintain optimal synaptic function are derived from dietary sources. As synapses are part of the neuronal membrane and are continuously being remodelled, the availability of sufficient levels of nutritional precursors (mainly uridine monophosphate, choline and omega-3 fatty acids) to make the phospholipids required to build neuronal membranes may have beneficial effects on synaptic degeneration in AD. In addition, B-vitamins, phospholipids and other micronutrients act as cofactors to enhance the supply of precursors required to make neuronal membranes and synapses. Despite this, no randomized controlled trial has hitherto provided evidence that any single nutrient has a beneficial effect on cognition or lowers the risk for AD. However, a multi-target approach using combinations of (micro)nutrients might have beneficial effects on cognitive function in neurodegenerative brain disorders like AD leading to synaptic degeneration. Here we review the clinical evidence for supplementation, based on a multi-target approach with a focus on key nutrients with a proposed role in synaptic dysfunction. Based on preclinical evidence, a nutrient mixture, Souvenaid(®) (Nutricia N.V., Zoetermeer, The Netherlands) was developed. Clinical trials with Souvenaid(®) have shown improved memory performance in patients with mild AD. Further clinical trials to evaluate the effects of nutritional intervention in MCI and early dementia due to AD are on-going.

The effects of abrupt antipsychotic discontinuation in cognitively impaired older persons: a pilot study

BACKGROUND

Antipsychotic use for behavioural and psychological symptoms of dementia (BPSD) is controversial. Guidelines advise to reduce antipsychotics given the adverse effects and limited efficacy, to limit dose and treatment duration as well as to undertake discontinuation.

METHODS

A pilot study with 40 hospitalised geriatric cognitively impaired patients, in which the effects of abrupt antipsychotic discontinuation were investigated, using neuropsychiatric inventory (NPI) scores before and one month after discontinuation. Withdrawal symptoms were monitored thrice a day with a checklist during five consecutive days.

RESULTS

Participants (n = 40) had a mean age of 84 years (range 67-95) and 53% were male. The total mean baseline NPI score was 21 (SD 12) with predominantly behavioural rather than psychological disturbances. After abrupt discontinuation, mild withdrawal symptoms were observed in 72% of the patients, with frequencies of symptoms peaking on day 2 (53%) and day 3 (48%). After one month, 31 patients (85%) were still off antipsychotics and improved on the majority of NPI domains, with a total mean NPI score decreasing from 18 (SD 13) to 12 (SD 8, p = 0.003). In the relapse group, there was no deterioration associated with the abrupt discontinuation and subsequent resumption of therapy with a total mean NPI score decreasing from 31 (SD 12) at baseline to 27 (SD 8) at one-month follow-up (p = 0.345).

CONCLUSION

Abrupt antipsychotic discontinuation appears to be feasible in older individuals with BPSD. Systematically performed discontinuation efforts in clinical practice are needed to differentiate between patients where antipsychotics have no added value and patients where the benefits outweigh the risks.

A prospective study on the prevalence and risk factors of poststroke depression

Background and Purpose

Poststroke depression (PSD) is common. Early detection of depressive symptoms and identification of patients at risk for PSD are important as PSD negatively affects stroke outcome and costs of medical care. Therefore, the aim of this study was to determine incidence and risk factors for PSD at 3 months after stroke.

Methods

We conducted a prospective, longitudinal epidemiological study aiming to determine incidence and risk factors for PSD at 1, 3, 6, 12 and 18 months poststroke. The present data analysis covers the convalescent phase of 3 months poststroke. Participants in this study were inpatients, admitted to a stroke unit with first or recurrent stroke. Demographic data and vascular risk factors were collected and patients were evaluated at baseline and 3 months poststroke for functional and cognitive deficits, stroke characteristics, stroke severity and stroke outcome. Signs and symptoms of depression were quantified by means of the Cornell Scale for Depression (CSD) and Montgomery and Åsberg Depression Rating Scale (MADRS). Significantly associated variables from univariate analysis were analyzed by using multiple linear and logistic regression methods.

Results

Data analysis was performed in 135 patients who completed follow-up assessments at 3 months poststroke. Depression (CSD score ≥8) was diagnosed in 28.1% of the patients. Patients with PSD were significantly more dependent with regard to activities of daily living (ADL) and displayed more severe physical and cognitive impairment than patients without PSD. A higher prevalence of speech and language dysfunction and apraxia were observed in patients with PSD (36.8 and 34.3%, respectively) compared to non-depressed stroke patients (19.6 and 12.4%; p = 0.036 and p = 0.004, respectively). Applying multiple linear regressions, cognitive impairment and reduced mobility as part of the Stroke Impact Scale were independently associated with PSD, as scored using CSD and MADRS (r² = 0.269 and r² = 0.474, respectively).

Conclusions

The risk of developing PSD is increased in patients with more functional and cognitive impairment, greater dependency with regard to ADL functions and with occurrence of speech and language dysfunctions and apraxia. Multiple regression models indicated that the most determining features for depression risk in the convalescent phase after stroke include reduced mobility and cognitive impairment. Further studies on risk factors for PSD are essential, given its negative impact on rehabilitation and quality of life. Identification of risk factors for PSD may allow more efficacious preventive measures and early implementation of adequate antidepressive treatment.

Alzheimer risk associated with a copy number variation in the complement receptor 1 increasing C3b/C4b binding sites

Two multicentre genome-wide association (GWA) studies provided substantial evidence, implicating the complement receptor 1 gene (CR1) in Alzheimer disease (AD) genetic etiology. CR1 encodes a large transmembrane receptor with a crucial role in the immune complement cascade. We performed a genetic follow-up of the GWA CR1 association in a Flanders-Belgian cohort (n=1883), and investigated the effect of single-nucleotide polymorphisms (SNPs) located in the CR1 locus on AD risk and cerebrospinal fluid (CSF) biomarker levels. We obtained significant association (P(adj)<0.03; odds ratio (OR)=1.24 (95% confidence interval (CI): 1.02-1.51)) for one CR1 risk haplotype, and haplotype association was strongest in individuals carrying apolipoprotein E (APOE) ɛ4 alleles (P(adj)<0.006; OR=1.50 (95% CI: 1.08-2.09)). Also, four SNPs correlated with increased CSF amyloid Aβ₁₋₄₂ levels, suggesting a role for the CR1 protein in Aβ metabolism. Moreover, we quantified a low-copy repeat (LCR)-associated copy number variation (CNV) in CR1, producing different CR1 isoforms, CR1-F and CR1-S, and obtained significant association in carriers of CR1-S. We replicated the CR1 CNV association finding in a French cohort (n=2003) and calculated in the combined cohorts, an OR of 1.32; 95% CI: 1.10-1.59 (P=0.0025). Our data showed that the common AD risk association may well be explained by the presence of CR1-S increasing the number of C3b/C4b and cofactor activity sites and AD risk with 30% in CR1-S carriers. How precisely the different functional role of CR1-S in the immune complement cascade contributes to AD pathogenesis will need additional functional studies.

APOE and Alzheimer disease: a major gene with semi-dominant inheritance

Apolipoprotein E (APOE) dependent lifetime risks (LTRs) for Alzheimer Disease (AD) are currently not accurately known and odds ratios alone are insufficient to assess these risks. We calculated AD LTR in 7351 cases and 10 132 controls from Caucasian ancestry using Rochester (USA) incidence data. At the age of 85 the LTR of AD without reference to APOE genotype was 11% in males and 14% in females. At the same age, this risk ranged from 51% for APOE44 male carriers to 60% for APOE44 female carriers, and from 23% for APOE34 male carriers to 30% for APOE34 female carriers, consistent with semi-dominant inheritance of a moderately penetrant gene. Using PAQUID (France) incidence data, estimates were globally similar except that at age 85 the LTRs reached 68 and 35% for APOE 44 and APOE 34 female carriers, respectively. These risks are more similar to those of major genes in Mendelian diseases, such as BRCA1 in breast cancer, than those of low-risk common alleles identified by recent GWAS in complex diseases. In addition, stratification of our data by age groups clearly demonstrates that APOE4 is a risk factor not only for late-onset but for early-onset AD as well. Together, these results urge a reappraisal of the impact of APOE in Alzheimer disease.

Verbal cued recall as a predictor of conversion to Alzheimer's disease in Mild Cognitive Impairment

OBJECTIVE

This study was set up to investigate whether neuropsychological tests are able to predict conversion to AD among Mild Cognitive Impairment (MCI) patients.

METHODS

At baseline the cognitive part of the Cambridge Examination for Mental Disorders of the Elderly (CAMCOG), the Mini Mental Status Examination (MMSE), the Geriatric Depression Scale (GDS), a Dutch variation of Rey's Auditory Verbal Learning Test, the Memory Impairment Screen plus (MISplus) and the Visual Association Test (VAT) were administered to 40 patients diagnosed with MCI. After 18 months, MCI-patients were reassessed and a follow-up diagnosis was established. Of those who were seen for follow-up (n = 31), seven fulfilled (NINCDS-ADRDA) criteria of probable AD, while 24 did not convert.

RESULTS

A binary logistic regression analysis showed that the MISplus contributed most to the prediction of conversion (OR = 0.28, 95% CI 0.099-0.790). With a cut-off of 2 out of 6, a positive predictive value of 71.5%, a negative predictive value of 91.5% and an overall diagnostic accuracy of 87.0% were achieved.

CONCLUSIONS

This prospective, longitudinal study shows that a score of 0 or 1 out of 6 on the MISplus may be a good indicator of future (within 18 months) progression to AD among MCI-patients.

Lrrk2 R1441C parkinsonism is clinically similar to sporadic Parkinson disease

OBJECTIVE

Leucine-rich repeat kinase 2 (LRRK2) mutations are the most common cause of Parkinson disease (PD). Several dominantly inherited pathogenic substitutions have been identified in different domains of the Lrrk2 protein. Herein, we characterize the clinical and genetic features associated with Lrrk2 p.R1441C.

METHODS

We identified 33 affected and 15 unaffected LRRK2 c.4321C>T (p.R1441C) mutation carriers through an international consortium originating from three continents. The age-specific cumulative incidence of PD was calculated by Kaplan-Meier analysis.

RESULTS

The clinical presentation of Lrrk2 p.R1441C carriers was similar to sporadic PD and Lrrk2 p.G2019S parkinsonism. The mean age at onset for parkinsonism was 60 years, range 30-79 years; fewer than 20% of the patients had symptoms before the age 50 years, while by 75 years >90% of them had developed symptoms. Haplotype analysis suggests four independent founders for the p.R1441C mutation.

CONCLUSIONS

The distribution in age at onset and clinical features in Lrrk2 p.R1441C patients are similar to idiopathic and Lrrk2 p.G2019S parkinsonism. Several independent founders of the p.R1441C substitution suggest this site is prone to recurrent mutagenesis.

Progranulin locus deletion in frontotemporal dementia

Ubiquitin-positive, tau-negative, frontotemporal dementia (FTD) is caused by null mutations in progranulin (PGRN; HUGO gene symbol GRN), suggesting a haploinsufficiency mechanism. Since whole gene deletions also lead to the loss of a functional allele, we performed systematic quantitative analyses of PGRN in a series of 103 Belgian FTD patients. We identified in one patient (1%) a genomic deletion that was absent in 267 control individuals. The deleted segment was between 54 and 69 kb in length and comprised PGRN and two centromeric neighboring genes RPIP8 (HUGO gene symbol RUNDC3A) and SLC25A39. The patient presented clinically with typical FTD without additional symptoms, consistent with haploinsufficiency of PGRN being the only gene contributing to the disease phenotype. This study demonstrates that reduced PGRN in absence of mutant protein is sufficient to cause neurodegeneration and that previously reported PGRN mutation frequencies are underestimated.

Within-session practice effect on paced auditory serial addition test in multiple sclerosis

The paced auditory serial addition test (PASAT) is increasingly used in multiple sclerosis (MS) studies. Since these studies rely on repeated assessments with relatively short inter-test intervals, practice effects can be a confounding factor. We examined intra-session PASAT practice effects in 70 relapsing remitting (RR) and 40 secondary progressive (SP) patients. The average number of correct answers increased from 39.6 ± 11.7 in the first PASAT run to 43.8 ± 11.4 in the second run for the RR group, and from 39.1 ± 11.6 to 41.8 ± 13.3 in the SP group. PASAT scores showed a consistent decrease when comparing the second half of each test to the first half for both patient groups, and for both runs. Items for which the answer was a number greater than 9 had the same discrimination ability as other test items, but were significantly more difficult. A simulation of `single-button' responses supported the use of the simplified scoring method which is currently used in fMRI studies. Our results demonstrate a within-session PASAT practice effect in MS, as well as a fatigability effect for both patient groups.

Differentiation between mild cognitive impairment, Alzheimer's disease and depression by means of cued recall

BACKGROUND

Discriminating Alzheimer's disease (AD) and mild cognitive impairment (MCI) from depression is a challenge in psychogeriatric medicine. A study was set up to ascertain whether cued recall could be useful in differentiating early AD and MCI from depression among elderly individuals.

METHOD

The Visual Association Test (VAT) and the Memory Impairment Screen-plus (MIS-plus) were administered together with the Mini-Mental State Examination (MMSE) and the Geriatric Depression Scale (GDS) to 40 MCI patients, 35 mild AD patients, 46 depressed patients and 52 healthy control subjects.

RESULTS

A one-way analysis of variance (ANOVA) followed by post-hoc Scheffé tests showed that AD patients had significantly lower cued recall scores (i.e. combined VAT and MIS-plus scores) than MCI patients, who in turn had lower scores than depressed patients. The scores of depressed patients and controls were not significantly different. Discriminant analysis revealed that 94% of the AD patients and 96% of the depressed patients could be classified correctly by means of the GDS and the cued recall sores. Receiver operating characteristic (ROC) curves identified an optimal cut-off score of 8 (maximum score 12) for differentiating AD and MCI patients from depressed elderly patients and controls. Applying this cut-off, a sensitivity of 83% (58%) and a specificity of 85% (85%) was obtained when differentiating AD (MCI) from depression.

CONCLUSIONS

Cued recall, operationalized by the combined scores of VAT and MIS-plus, is a useful method for differentiating AD patients from depressed individuals and healthy controls. Probably because of the great heterogeneity among MCI patients, the diagnostic power of cued recall decreases when applied to differentiate MCI from depression.

Volumetric evaluation of upper extremities in 250 healthy persons

BACKGROUND AND PURPOSE

Upper extremity oedema frequently occurs as a complication of several diseases. The aim of this study was to establish normative data for upper extremity volumes with a modified water displacement method. These data were used to develop predictive formulas helpful in detecting abnormal swelling.

SUBJECTS AND METHODS

Upper extremities of 250 healthy subjects (138 men and 112 women) were measured by water displacement.

RESULTS

A mean difference of 3.0% (3.2%) between right and left arm (forearm) was found. Intra-class correlation coefficients were 0.99 for intra-rater and inter-rater reliabilities. Coefficient of variation was 0.23%. To predict the premorbid volume of an oedematous arm, prediction formulas were constructed.

DISCUSSION AND CONCLUSION

Water displacement as used in this study is a highly reliable technique for volume measurement of upper extremities. This technique was applied to gather normative data for upper extremity volumes. We suggest that this technique can be used in daily clinical practice for the evaluation of upper extremity oedema or atrophy caused by various diseases as well as for volume monitoring. Prediction formulas can be used to define abnormal swelling.

Mild Cognitive Impairment: What’s in a Name?

BACKGROUND

Nowadays the term mild cognitive impairment (MCI) is used to fill the gap between cognitive changes associated with normal ageing and those associated with dementia. Despite some agreement in general definitions, MCI is still a heterogeneous clinical syndrome for which no DSM-IV criteria have yet been established. Criteria by Petersen et al. are presently the most applied in clinical practice. Moreover, little attention has been paid to the specific relation between MCI and depression.

OBJECTIVE

This review highlights some concerns about the concept of MCI and provides guidelines within the field of neuropsychology to solve them. In a second part, the paper focuses on the specific relationship between depression in the elderly and MCI.

RESULTS

We hypothesize that certain test instruments can be used to operationalize the criteria proposed by Petersen et al. Moreover, we suggest that cued recall might be of help to differentiate between progressive and non-progressive MCI. Concerning the specific relation between depression and MCI, we assume that elderly depression with concomitant cognitive problems can be seen as an MCI.

CONCLUSION

The proposed adjustments and additions (neuropsychological instruments and the incorporation of depressive symptoms) in the diagnostic flowchart of Petersen may serve as useful tools for clinicians when making a diagnosis of MCI.

Regional distribution of biogenic amines, amino acids and cholinergic markers in the CNS of the C57BL/6 strain

A reliable extrapolation of neurochemical alterations from a mouse model to human metabolic brain disease requires knowledge of neurotransmitter levels and related compounds in control mouse brain. C57BL/6 is a widely used background strain for knockout and transgenic mouse models. A prerequisite for reliable extrapolation from mouse brain to the human condition is the existence of analogous distribution patterns of neurotransmitters and related compounds in control mouse and human brain. We analysed regional distribution patterns of biogenic amines, neurotransmitter and non-neurotransmitter amino acids, and cholinergic markers. Distribution patterns were compared with known neurotransmitter pathways in human brain. The present study provides a reference work for future analyses of neurotransmitters and related compounds in mouse models bred in a C57BL/6 background strain.

Amino acids and biogenic amines in cerebrospinal fluid of patients with Parkinson's disease

To study changes in amino acid metabolism and biogenic amines in Parkinson's disease, we set up a prospective study and measured biogenic amines, their main metabolites, and 22 different amino acids, in cerebrospinal fluid of Parkinson's disease patients (n = 24) and age-matched controls (n = 30). A trend toward higher dopamine levels in Parkinson's disease patients was interpreted as an effect of treatment with levodopa and/or selegiline. Significantly lower concentrations of the dopamine metabolite 3,4-dihydroxyphenylacetic acid in the Parkinson's disease group might reflect dopaminergic cell loss. Our results revealed decreased serotonin catabolism that was interpreted as an effect of treatment with selegiline. Whereas all amino acid levels were unchanged, taurine was significantly lower in Parkinson's disease patients. Studies showed that taurine exerts a trophic action on the central nervous system. In this view, decreased taurine in a neurodegenerative disorder as Parkinson's disease deserves attention.

Prospective Belgian study of neurodegenerative and vascular dementia: APOE genotype effects

OBJECTIVE

The authors conducted a prospective study of neurodegenerative and vascular dementia in Belgium. Strict diagnostic inclusion criteria were used to include well defined patients and controls. The results of apolipoprotein E (APOE) genotype effect on risk and clinical characteristics are presented.

METHODS

APOE genotyping was performed in patients with probable Alzheimer's disease (AD) (n=504), frontotemporal dementia (FTD) (n=47), vascular dementia (VaD) (n=152), mixed dementia (n=132), mild cognitive impairment (MCI) (n=44), Parkinson's disease (PD) (n=30), dementia with Lewy bodies (DLB) (n=17), and multisystem atrophy (MSA)/progressive supranuclear palsy (PSP) (n=12).

RESULTS

The APOE allele frequencies of this Belgian control population (epsilon 2: 6.9%; epsilon 3: 76.2%; epsilon 4: 16.9%) did not differ from those reported for other white populations. AD, MCI, and mixed dementia patients had higher APOE epsilon 4 (32.9%, 38.6%, and 28.4% respectively) and lower APOE epsilon 3 (62.2%, 53.4%, and 66.3%) frequencies compared with controls, whereas only AD and mixed dementia patients had lower APOE epsilon 2 frequencies (4.9% and 5.3%). Apart from a borderline significant different distribution of APOE allele frequencies in VaD patients compared with controls, no other differences were detected. The influence of APOE epsilon 4 on clinical features of dementia was limited to lower age at onset in AD patients and a less pronounced negative correlation between age at onset and number of epsilon 4 alleles in MCI and mixed dementia patients.

CONCLUSIONS

This study confirmed the risk association between APOE epsilon 4 and AD. The observation that APOE epsilon 4 is associated with mixed dementia reflected the role of AD in the aetiopathogenesis of this condition. Although MCI is an aetiologically heterogeneous syndrome, the increased APOE epsilon 4 frequencies indicated that a large proportion of the MCI patients included in the study might be predisposed to develop AD.

Acquired crossed aphasia in dextral children revisited

In contrast to the estimated low incidence of crossed aphasia in dextral adults (among 1%), crossed aphasia in children has been considered a common finding for almost a century. However, reviewing the literature on crossed aphasia in dextrals (CAD) and its related topics from 1975 onward, we encountered only 5 children in a corpus of 180 cases (2.7%). Critical analysis rendered three of the reported cases ambiguous and hence not suitable to draw potentially relevant conclusions. In this review, the neurobehavioral manifestations of the two representative childhood CAD cases are analyzed and compared with adult CAD and acquired childhood aphasia (ACA). In the light of our findings, which support the position of innate cerebral specialization for language, the long-standing controversy as to whether lateralized hemispheric specialization for language is innate or develops progressively during maturation is briefly discussed.

The lateralized linguistic cerebellum: a review and a new hypothesis

During the past 2 decades the collaboration across disciplines and the methodologic and conceptual advances of contemporary neuroscience have brought about a substantial modification of the traditional view of the cerebellum as a mere coordinator of autonomic and somatic motor functions. Growing insights in the neuroanatomy of the cerebellum and its interconnections, evidence from functional neuroimaging and neurophysiological research, and advancements in clinical and experimental neuropsychology have established the view that the cerebellum participates in a much wider range of functions than conventionally accepted. This increase of insight has brought to the fore that the cerebellum modulates cognitive functioning of at least those parts of the brain to which it is reciprocally connected. This article reviews the recently acknowledged role of the cerebellum in cognition and addresses in more detail experimental and clinical data disclosing the modulatory role of the cerebellum in various non-motor language processes such as lexical retrieval, syntax, and language dynamics. In agreement with the findings indicating a topographical organization of the cerebellar structures involved in language pathology we advance the concept of a "lateralized linguistic cerebellum." In our view crossed cerebral diaschisis processes, reflecting a functional depression of supratentorial language areas due to reduced input via cerebellocortical pathways, might represent the relevant pathomechanism for linguistic deficits associated with cerebellar pathology.

The many faces of crossed aphasia in dextrals: report of nine cases and review of the literature

A substantial body of the aphasia literature has been devoted to the topic of crossed aphasia in dextrals (CAD) over the past century but still no theory exists that explains the anomalous organization of neurocognitive functions in this population. However, if strict selection criteria are applied only some cases of vascular CAD are reported in which the correlation between neurocognitive disturbances and the locus of the brain lesion is studied. This study describes nine new cases of vascular CAD who underwent in-depth neurolinguistic and neuropsychological investigations. Our analysis shows the semiological variability of CAD phenomena and the many faces of the lesion-behaviour relationships of this exceptional neurobiological condition.

Cerebellar neurocognition: a new avenue

The functional role of the cerebellum is traditionally defined as a mere coordinator of automatic and somatic motor functions. This view determined most of the clinical and experimental investigations of the functions of the cerebellum and overshadowed many attempts to expand its role to non-motor functions. However, during the past decades the collaboration across contemporary neuroscience disciplines has brought about a substantial modification of traditional thinking about the cerebellum. Converging evidence from different neuroscientific angles established the view that the human cerebellum participates in a much wider range of functions than conventionally accepted. Studies have brought to the fore that the cerebellum also modulates neurocognitive functions of at least these parts of the brain to which it is reciprocally connected. In less than two decades, the concept of 'cerebellar neurocognition' evolved from a mere afterthought to an exciting new multifaced area of contemporary neuroscientific investigations. Within this area, one of the major avenues of current research is the role of the cerebellum in non-motor language processing. This paper reviews the recently acknowledged role of the cerebellum in neurocognition and linguistic processes.

Headache as only symptom in multiple cervical artery dissection

We describe a patient with atypical headache as the only presenting symptom of spontaneous triple cervical artery dissection. As the patient suffered from arterial hypertension, a causative relation between headache and arterial hypertension was initially taken into consideration. However, four-vessel arteriography disclosed a dissection of both internal carotid arteries and the right vertebral artery. This unique case highlights the value of conventional arteriography for diagnosing cervical artery dissection. Since multiple cervical artery dissections are not rare, all cervical arteries should be examined by means of conventional arteriography when a dissection is suspected.

Biological and genetic markers of sporadic Alzheimer's disease

With the development of new treatments, there is an increasing need for early diagnosis of sporadic Alzheimer's disease. Therefore, biological markers allowing positive diagnosis early in the course of the disease are highly desirable. Cerebrospinal fluid levels of protein tau were shown to be significantly increased in patients with Alzheimer's disease. Although sensitivity is high, poor specificity limits the diagnostic value of this marker. The same is true for the 42 amino acid isoform of beta-amyloid protein that is significantly decreased in cerebrospinal fluid of Alzheimer's disease patients. However, combining both markers could improve specificity at least allowing differentiation between Alzheimer's disease, normal ageing and depressive pseudodementia. Other biological markers such as cerebrospinal fluid levels of neurotransmitters, cytokines or superoxide dismutase were shown to have even less diagnostic value. The apolipoprotein epsilon 4 allele is a risk factor for Alzheimer's disease but not a diagnostic marker as many individuals who inherit epsilon 4 do not develop the disease. Till now, a single diagnostic marker allowing discrimination between Alzheimer's disease and other dementias does not exist. Combined cerebrospinal fluid levels of beta-amyloid protein and tau protein might be used as a marker that helps discriminating Alzheimer's disease from normal ageing and depression.

Consequences of renal mass reduction on amino acid and biogenic amine levels in nephrectomized mice

Amino acid and biogenic amine changes were investigated in nephrectomized mice ten days postsurgery. Uremic mice exhibited changes in amino acid concentrations in plasma, urine and brain. Particularly plasma methionine, citrulline and arginine levels were significantly enhanced in nephrectomized mice compared to controls whereas serine was decreased. Urinary excretion of methionine, citrulline and alanine was higher in nephrectomized mice compared to controls whereas many amino acids were increased in brain of nephrectomized mice. Brain and urinary amino acid changes were more pronounced in the 75% than in the 50% nephrectomized mice. Brain norepinephrine and dopamine and its metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly increased whereas serotonin was decreased comparing the 75% nephrectomized mice to the sham-operated mice. This study demonstrates that at very early stages of renal insufficiency, specific amino acid and biogenic amine changes occur in plasma, urine and brain. These alterations might depend qualitatively and quantitatively on the degree of functional renal mass reduction.

Anomalous cerebral language organization: acquired crossed aphasia in a dextral child

Following a dramatic change of its reported incidence, it was only recently recognized that acquired crossed aphasia in dextral children represents a highly exceptional phenomenon. We describe in a three epoch time-frame model the aphasic and neurocognitive manifestations of an additional case and focus briefly on its anatomoclinical configurations. In our patient, a right parietal cortico-subcortical hemorrhagic lesion caused an initially severe aphasia. After remission of the global aphasic symptoms in the acute phase, an adynamic output disorder with relatively severe auditory-verbal comprehension disturbances developed. In addition to the adynamia of self-generated speech, formal language investigations performed 3 weeks postonset, revealed agrammatism, hypertonic dysarthria, and dysprosodia. A substantial improvement of the aphasic disorder was objectified 83 days postonset. Neuropsychological investigations disclosed both dominant and nondominant hemisphere dysfunctions. Reassessment of neurocognitive functions after a 10-year period evidenced discrete residual anomia, confined to visual confrontational naming and a discrete visuo-perceptual syndrome. Given the posterior localization of the lesion, the syndrome shift from global to predominantly adynamic aphasia represents a finding beyond the plausible anatomoclinical expectations holding in general for the uncrossed, classic types of childhood and adult aphasia. As the first representative of crossed aphasia in dextral children with an anomalous lesion-aphasia profile, our case provides evidence to enrich the discussion on lateralization and intrahemispherical organization of language functions in both childhood and adult aphasia.

Phonological agraphia following a focal anterior insulo-opercular infarction

Following a unique infarction, restricted to the left anterior insula and the adjacent part of the intrasylvian frontal opercular cortex, an 83-year-old right-handed patient acutely developed a severe speech disorder that evolved into mere mutism within a few hours. After rapid recovery from mutism, oral language was characterized by severe apraxia of speech. In-depth language investigations further disclosed an isolated, highly selective disturbance of the spelling system (phonological agraphia) which resolved rapidly. One year after onset of neurological symptoms, the apraxia of speech had almost completely receded. The anatomoclinical findings in this first representative of pure and nearly isolated phonological agraphia complement previous neuroanatomical and neurolinguistic accounts of phonological agraphia. The data not only seem to enrich current insights in the anatomical locus for phonological agraphia, they also seem to contribute to a further delineation of the insular role in phonologically mediated aphasic manifestations.

Pathophysiology of epilepsy

This work reviews the current knowledge on epileptogenesis and pathophysiology of epilepsy. Recently, gene defects underlying four monogenic epilepsies (generalized epilepsy with febrile seizures, autosomal dominant nocturnal frontal lobe epilepsy, benign familial neonatal convulsions and episodic ataxia type 1 with partial seizures) have been identified, shedding new light on the pathophysiology of epilepsy as these diseases are caused by ion channel mutations. Although epileptic syndromes differ pathophysiologically, common ictogenesis-related characteristics as increased neuronal excitability and synchronicity are shared as well as mechanisms involved in interictal-ictal transition. Emerging insights point to alterations of synaptic functions and intrinsic properties of neurons as common mechanisms underlying hyperexcitability. This work also reviews the neurochemical mechanisms of epilepsy. An imbalance between glutamate and gamma-aminobutyric acid neurotransmitter systems can lead to hyperexcitability but catecholaminergic neurotransmitter systems and opioid peptides were shown to play a role in epileptogenesis as well. An overview of currently available anti-epileptic drugs and their presumed mechanisms of action is given as an illustration of the neurochemistry of epileptogenesis. Most anti-epileptic drugs exert their anti-epileptic properties through only a few neurochemical mechanisms that are meanwhile basic pathophysiological mechanisms thought to cause seizures.

Loss of psychic self-activation after paramedian bithalamic infarction

BACKGROUND AND PURPOSE

Loss of psychic self-activation has been described after bilateral lesions to the globus pallidus, striatum, and white matter of the frontal lobes, but it is a very rare sign of bithalamic lesions. The exact functional-anatomic mechanism underlying loss of psychic self-activation following bithalamic lesions remains to be elucidated.

CASE DESCRIPTION

We present clinical, neuropsychological, structural, and functional neuroimaging data of an 18-month follow-up period of a man with prominent loss of psychic self-activation after coronary arteriography. Except for memory decline, accompanying symptoms remained restricted to the acute phase. The neurobehavioral syndrome consisted mainly of apathy, indifference, poor motivation, and flattened affect, and this remained unchanged during the entire follow-up period. MRI showed a bithalamic infarction involving the nucleus medialis thalami bilaterally. Single-photon emission CT revealed a severe relative hypoperfusion of both thalami, a relative hypoperfusion of both nuclei caudati, and a relative hypoperfusion mesiofrontally.

CONCLUSIONS

Single-photon emission CT data support the hypothesis that the neurobehavioral manifestations after bithalamic paramedian infarction are caused by disruption of the striatal-ventral pallidal-thalamic-frontomesial limbic loop. Probably, bilateral disruption at different levels of the striatal-ventral pallidal-thalamic-frontomesial loop may lead to a similar clinical picture consisting of loss of psychic self-activation.