Evaluation of Differential Diagnostics Potential of Uniform Data Set 2 Neuropsychology Battery Using Alzheimer's Disease Biomarkers

OBJECTIVE

This study aims to evaluate the efficacy of the Uniform Data Set (UDS) 2 battery in distinguishing between individuals with mild cognitive impairment (MCI) attributable to Alzheimer's disease (MCI-AD) and those with MCI due to other causes (MCI-nonAD), based on contemporary AT(N) biomarker criteria. Despite the implementation of the novel UDS 3 battery, the UDS 2 battery is still used in several non-English-speaking countries.

METHODS

We employed a cross-sectional design. A total of 113 Czech participants with MCI underwent a comprehensive diagnostic assessment, including cerebrospinal fluid biomarker evaluation, resulting in two groups: 45 individuals with prodromal AD (A+T+) and 68 participants with non-Alzheimer's pathological changes or normal AD biomarkers (A-). Multivariable logistic regression analyses were employed with neuropsychological test scores and demographic variables as predictors and AD status as an outcome. Model 1 included UDS 2 scores that differed between AD and non-AD groups (Logical Memory delayed recall), Model 2 employed also Letter Fluency and Rey's Auditory Verbal Learning Test (RAVLT). The two models were compared using area under the receiver operating characteristic curves. We also created separate logistic regression models for each of the UDS 2 scores.

RESULTS

Worse performance in delayed recall of Logical Memory significantly predicted the presence of positive AD biomarkers. In addition, the inclusion of Letter Fluency RAVLT into the model significantly enhanced its discriminative capacity.

CONCLUSION

Our findings demonstrate that using Letter Fluency and RAVLT alongside the UDS 2 battery can enhance its potential for differential diagnostics.

Structural connectivity-based predictors of cognitive impairment in stroke patients attributable to aging

Despite the rising global burden of stroke and its socio-economic implications, the neuroimaging predictors of subsequent cognitive impairment are still poorly understood. We address this issue by studying the relationship of white matter integrity assessed within ten days after stroke and patients' cognitive status one year after the attack. Using diffusion-weighted imaging, we apply the Tract-Based Spatial Statistics analysis and construct individual structural connectivity matrices by employing deterministic tractography. We further quantify the graph-theoretical properties of individual networks. The Tract-Based Spatial Statistic did identify lower fractional anisotropy as a predictor of cognitive status, although this effect was mostly attributable to the age-related white matter integrity decline. We further observed the effect of age propagating into other levels of analysis. Specifically, in the structural connectivity approach we identified pairs of regions significantly correlated with clinical scales, namely memory, attention, and visuospatial functions. However, none of them persisted after the age correction. Finally, the graph-theoretical measures appeared to be more robust towards the effect of age, but still were not sensitive enough to capture a relationship with clinical scales. In conclusion, the effect of age is a dominant confounder especially in older cohorts, and unless appropriately addressed, may falsely drive the results of the predictive modelling.

Emotional prosody recognition is impaired in Alzheimer’s disease

Background

The ability to understand emotions is often disturbed in patients with cognitive impairments. Right temporal lobe structures play a crucial role in emotional processing, especially the amygdala, temporal pole (TP), superior temporal sulcus (STS), and anterior cingulate (AC). Those regions are affected in early stages of Alzheimer´s disease (AD). The aim of our study was to evaluate emotional prosody recognition (EPR) in participants with amnestic mild cognitive impairment (aMCI) due to AD, AD dementia patients, and cognitively healthy controls and to measure volumes or thickness of the brain structures involved in this process. In addition, we correlated EPR score to cognitive impairment as measured by MMSE. The receiver operating characteristic (ROC) analysis was used to assess the ability of EPR tests to differentiate the control group from the aMCI and dementia groups.

Methods

Eighty-nine participants from the Czech Brain Aging Study: 43 aMCI due to AD, 36 AD dementia, and 23 controls, underwent Prosody Emotional Recognition Test. This experimental test included the playback of 25 sentences with neutral meaning each recorded with different emotional prosody (happiness, sadness, fear, disgust, anger). Volume of the amygdala and thickness of the TP, STS, and rostral and caudal parts of AC (RAC and CAC) were measured using FreeSurfer algorithm software. ANCOVA was used to evaluate EPR score differences. ROC analysis was used to assess the ability of EPR test to differentiate the control group from the aMCI and dementia groups. The Pearson’s correlation coefficients were calculated to explore relationships between EPR scores, structural brain measures, and MMSE.

Results

EPR was lower in the dementia and aMCI groups compared with controls. EPR total score had high sensitivity in distinguishing between not only controls and patients, but also controls and aMCI, controls and dementia, and aMCI and dementia. EPR decreased with disease severity as it correlated with MMSE. There was a significant positive correlation of EPR and thickness of the right TP, STS, and bilateral RAC.

Conclusions

EPR is impaired in AD dementia and aMCI due to AD. These data suggest that the broad range of AD symptoms may include specific deficits in the emotional sphere which further complicate the patient’s quality of life.

Progression from Subjective Cognitive Decline to Mild Cognitive Impairment or Dementia: The Role of Baseline Cognitive Performance

Background: Older adults with subjective cognitive decline (SCD) are at an increased risk of progression to mild cognitive impairment (MCI) or dementia. However, few have examined the specific cognitive tests that are associated with progression. Objective: This study examined performance on 18 neuropsychological tests among participants with SCD who later progressed to MCI or dementia. Methods: We included 131 participants from the Czech Brain Aging Study that had SCD at baseline. They completed a comprehensive neuropsychological battery including cognitive tests from the Uniform Data Set 2.0 enriched by the verbal memory test Rey Auditory Verbal Learning Test (RAVLT) and Rey-Osterrieth Complex Figure Test (ROCFT). Results: Fifty-five participants progressed: 53% to non-amnestic MCI (naMCI), 44% to amnestic MCI (aMCI), and 4% to dementia. Scoring one SD below the mean at baseline on the RAVLT 1 and RAVLT 1–5 was associated with 133% (RAVLT 1; HR: 2.33 [1.50, 3.62]) and 122% (RAVLT 1–5; HR: 2.22 [1.55, 3.16]) greater risk of progression to MCI or dementia over 3.84 years on average. Worse performance on the RAVLT 5, RAVLT 1–5, RAVLT 30, and ROCFT–Recall was associated with progression to aMCI whereas worse performance on the RAVLT 1, TMT B, and Boston Naming Test was associated with progression to naMCI. Conclusion: At baseline, lower verbal memory performance was most strongly associated with progression to aMCI whereas lower executive or language performance was most strongly associated with progression to naMCI.

APOEɛ4 Allele Moderates the Association Between Basal Forebrain Nuclei Volumes and Allocentric Navigation in Older Adults Without Dementia

BACKGROUND

Cholinergic deficit and medial temporal lobe (MTL) atrophy are hallmarks of Alzheimer's disease (AD) leading to early allocentric spatial navigation (aSN) impairment. APOEɛ4 allele (E4) is a major genetic risk factor for late-onset AD and contributes to cholinergic dysfunction. Basal forebrain (BF) nuclei, the major source of acetylcholine, project into multiple brain regions and, along with MTL and prefrontal cortex (PFC), are involved in aSN processing.

OBJECTIVE

We aimed to determine different contributions of individual BF nuclei atrophy to aSN in E4 positive and E4 negative older adults without dementia and assess whether they operate on aSN through MTL and PFC or independently from these structures.

METHODS

120 participants (60 E4 positive, 60 E4 negative) from the Czech Brain Aging Study underwent structural MRI and aSN testing in real-space arena setting. Hippocampal and BF nuclei volumes and entorhinal cortex and PFC thickness were obtained. Associations between brain regions involved in aSN were assessed using MANOVA and complex model of mutual relationships was built using structural equation modelling (SEM).

RESULTS

Path analysis based on SEM modeling revealed that BF Ch1-2, Ch4p, and Ch4ai nuclei volumes were indirectly associated with aSN performance through MTL (pch1 - 2 = 0.039; pch4p = 0.042) and PFC (pch4ai = 0.044). In the E4 negative group, aSN was indirectly associated with Ch1-2 nuclei volumes (p = 0.015), while in the E4 positive group, there was indirect effect of Ch4p nucleus (p = 0.035).

CONCLUSION

Our findings suggest that in older adults without dementia, BF nuclei affect aSN processing indirectly, through MTL and PFC, and that APOE E4 moderates these associations.

Reducing misclassification of mild cognitive impairment based on base rate information from the Uniform data set

The current study aimed to define and validate the criteria for characterizing possible and probable cognitive deficits based on the psychometric approach using the Uniform data set Czech version (UDS-CZ 2.0) to reduce the rate of misdiagnosis. We computed the prevalence of low scores on the 14 subtests of UDS-CZ 2.0 in a normative sample of healthy older adults and validated criteria for possible and probable cognitive impairment on the sample of amnestic Mild Cognitive Impairment (MCI) patients. The misclassification rate of the validation sample using psychometrically derived criteria remained low: for classification as possible impairment, we found 66-76% correct classification in the clinical sample and only 2-8% false positives in the healthy control validation sample, similar results were obtained for probable cognitive impairment. Our findings offer a psychometric approach and a computational tool to minimize the misdiagnosis of mild cognitive impairment compared to traditional criteria for MCI.

The Effect of Mindfulness-Based Stress Reduction (MBSR) on Depression, Cognition, and Immunity in Mild Cognitive Impairment: A Pilot Feasibility Study

BACKGROUND

Mindfulness-based programs have shown a promising effect on several health factors associated with increased risk of dementia and the conversion from mild cognitive impairment (MCI) to dementia such as depression, stress, cognitive decline, immune system and brain structural and functional changes. Studies on mindfulness in MCI subjects are sparse and frequently lack control intervention groups.

OBJECTIVE

To determine the feasibility and the effect of mindfulness-based stress reduction (MBSR) practice on depression, cognition and immunity in MCI compared to cognitive training.

METHODS

Twenty-eight MCI subjects were randomly assigned to two groups. MBSR group underwent 8-week MBSR program. Control group underwent 8-week cognitive training. Their cognitive and immunological profiles and level of depressive symptoms were examined at baseline, after each 8-week intervention (visit 2, V2) and six months after each intervention (visit 3, V3). MBSR participants completed feasibility questionnaire at V2.

RESULTS

Twenty MCI patients completed the study (MBSR group n=12, control group n=8). MBSR group showed significant reduction in depressive symptoms at both V2 (p=0.03) and V3 (p=0.0461) compared to the baseline. There was a minimal effect on cognition - a group comparison analysis showed better psychomotor speed in the MBSR group compared to the control group at V2 (p=0.0493) but not at V3. There was a detectable change in immunological profiles in both groups, more pronounced in the MBSR group. Participants checked only positive/neutral answers concerning the attractivity/length of MBSR intervention. More severe cognitive decline (PVLT≤36) was associated with the lower adherence to home practice.

CONCLUSION

MBSR is well-accepted potentially promising intervention with positive effect on cognition, depressive symptoms and immunological profile.

Cognitive Impairment in Old Age

Abstract. A decline in cognitive functioning is part of physiological aging. Accelerated cognitive decline is frequently linked to pathological changes, mostly due to Alzheimer’s Disease (AD), but is present also in Mild Cognitive Impairment (MCI) which is a predictor of transition to dementia. This review aims to summarize possible preventive biological and psychological treatments in different stages of lifespan to avoid more rapid cognitive decline and prevent pathological aging. Psychophysiological approaches aim to prevent brain damage and inflammation, two factors playing probably a major role in middle and old age. Interventions on working memory and imagery, using “cognitive reserve,” are beneficial for tolerating neuropathological age-related changes. Some controversial results are outlined, suggesting explanations for the inconsistency of findings. Although clear evidence from interventional studies is lacking, it seems that multi-domain interventions should be recommended to avoid or delay cognitive decline.

Assessment of Memory Impairment in Early Diagnosis of Alzheimer's Disease

Memory impairment has been considered as one of the earliest clinical hallmarks of Alzheimer's disease. This paper summarizes recent progress in the assessment of memory impairment in predementia stages. New promising approaches of memory assessment include evaluation of longitudinal cognitive changes, assessment of long-term memory loss, evaluation of subjective cognitive concerns and testing of other memory modalities, such as spatial memory. In addition, we describe new challenging memory tests based on memory binding paradigms that have been recently developed and are currently being validated.

Homocysteine and Real-Space Navigation Performance among Non-Demented Older Adults

BACKGROUND

High plasma homocysteine (Hcy) level is related to higher risk of Alzheimer's disease (AD) and lower cognitive performance in older adults.

OBJECTIVE

To assess the association between plasma Hcy level and real-space navigation performance and the role of vascular risk and protective factors, APOE status, and white matter lesions (WML) on this association.

METHODS

Ninety-two non-demented older adults (29 with amnestic mild cognitive impairment, 46 with subjective cognitive decline, and 17 cognitively normal older adults) underwent spatial navigation testing of egocentric, allocentric, and mixed navigation in a real-space analogue of the Morris water maze, neuropsychological examination, blood collection, and MRI brain scan with evaluation of WML.

RESULTS

In the regression analyses controlling for age, gender, education, and depressive symptoms, higher plasma Hcy level was related to worse mixed and egocentric (β= 0.31; p = 0.003 and β= 0.23; p = 0.017) but not allocentric (p > 0.05) navigation performance. Additional controlling for vascular risk and protective factors, WML, and APOE status did not modify the results. High total cholesterol and low vitamin B12 and folate levels increased the adverse effect of Hcy on egocentric and mixed navigation. WML did not explain the association between plasma Hcy level and navigation performance.

CONCLUSION

Elevated plasma Hcy level may affect real-space navigation performance above and beyond vascular brain changes. This association may be magnified in the presence of high total cholesterol and low folate or vitamin B12 levels. Attention to the level of plasma Hcy may be a viable intervention strategy to prevent decline in spatial navigation in non-demented older adults.

Discovery and Identification of an Endogenous Metabolite of Tramiprosate and Its Prodrug ALZ-801 that Inhibits Beta Amyloid Oligomer Formation in the Human Brain

BACKGROUND

ALZ-801 is an oral, small-molecule inhibitor of beta amyloid (Aβ) oligomer formation in clinical development for Alzheimer's disease (AD). ALZ-801 is a prodrug of tramiprosate with improved pharmacokinetic properties and gastrointestinal tolerability. During clinical studies, we discovered that the primary metabolite of tramiprosate and its prodrug ALZ-801, 3-sulfopropanoic acid (3-SPA), is an endogenous molecule in the human brain and present in the cerebrospinal fluid (CSF) of patients with AD and other neurodegenerative brain diseases.

OBJECTIVE

The objectives of this research were to (1) identify and confirm the presence of 3-SPA in CSF samples from elderly, drug-naïve patients with memory deficits; (2) quantify the levels of 3-SPA in the CSF of patients with AD from tramiprosate phase III North American (NA) trial; (3) evaluate the in vitro anti-Aβ42 oligomer activity of 3-SPA; and (4) characterize the pharmacokinetics and brain-penetration properties of 3-SPA.

METHODS

Lumbar CSF samples from 64 drug-naïve patients with cognitive deficits (Mini-Mental State Examination [MMSE] score range 15-30) and six patients with AD treated with tramiprosate 150 mg twice daily in the phase III trial, at week 78, were analyzed. We used liquid chromatography-tandem mass spectrometry to confirm the structural molecular identity of endogenous 3-SPA with a 3-SPA reference standard and ion-mobility spectrometry-mass spectrometry with molecular dynamics to characterize interactions of 3-SPA with Aβ42 monomers, and the resultant conformational alterations. Rat studies using oral (30 mg/kg) and intravenous (10 mg/kg) doses were conducted to characterize the pharmacokinetic properties and brain penetration of 3-SPA.

RESULTS

We confirmed the presence of 3-SPA in the CSF of drug-naïve patients with cognitive deficits (mean concentration 11.7 ± 4.3 nM). The mean concentration of 3-SPA in patients with AD treated with tramiprosate was 135 ± 51 nM. In vitro studies revealed a multi-ligand interaction of 3-SPA with monomeric Aβ42 that inhibits the aggregation of Aβ42 into small oligomers. Comparisons of the molecular interactions of tramiprosate and 3-SPA with Aβ42 are also presented. Furthermore, in rat preclinical studies, 3-SPA displayed 100% oral bioavailability and 25% brain penetration, indicating that the metabolite is well absorbed and crosses the blood-brain barrier.

CONCLUSIONS

We confirmed the endogenous presence of 3-SPA, the major metabolite of tramiprosate, in the CSF of drug-naïve elderly patients with memory deficits due to AD and a variety of other neurodegenerative disorders. The levels of 3-SPA were up to 12.6-fold greater in patients with AD receiving tramiprosate than in drug-naïve patients. In addition, we showed that 3-SPA has potent anti-Aβ oligomer activity, inhibiting aggregation of Aβ42 into small oligomers with efficacy comparable to that of tramiprosate. 3-SPA displays excellent oral availability and brain penetration in rats, suggesting that the higher CSF concentrations of 3-SPA in the human brain after oral administration of ALZ-801 or tramiprosate (and subsequent conversion to 3-SPA) result from the penetration of the metabolite into the central nervous system. These data suggest that 3-SPA is an endogenous agent with potential activity stabilizing the conformational flexibility of Aβ monomers that, in turn, inhibit Aβ misfolding and formation of soluble toxic Aβ oligomers in humans, thereby preventing the initial pathogenic step in the progression of AD. Clinical improvements observed in patients with AD carrying the ε4 allele of the apolipoprotein E gene in tramiprosate phase III studies may in part be explained by the therapeutic effects of excess levels of the metabolite in the brains of these patients. The potential protective role of 3-SPA in AD pathogenesis, as well as its therapeutic role in AD and other neurodegenerative disorders, warrants further investigation.

Clock drawing test in screening for Alzheimer's dementia and mild cognitive impairment in clinical practice

OBJECTIVES

The clock drawing test (CDT) is a commonly used brief cognitive measure. We evaluated diagnostic accuracy of subjective ratings of CDT by physicians (with/without specialty in cognitive neurology) and neuropsychologists in discriminating amnestic mild cognitive impairment (aMCI), Alzheimer's dementia (AD) and cognitively healthy older adults. We further compared the diagnostic accuracy of subjective categorical ratings with complex scoring of CDT.

METHODS

Three cognitive neurologists, three neuropsychologists and six neurology residents without experience in cognitive neurology blinded to the diagnosis rated 187 CDTs (50 mild AD, 49 aMCI and 88 cognitively healthy older adults) using a "yes" (abnormal) versus "suspected" versus "no" (normal) classification. The rating suspected was combined with yes or no to obtain two sets of sensitivity estimates. We also used a 17-point CDT rating system.

RESULTS

When using the categorical rating, neuropsychologists had highest sensitivity (89%) in differentiating patients with mild AD (yes/suspected versus no), followed by neurologic residents (80%) and cognitive neurologists (79%). When differentiating patients with aMCI (yes/suspected versus no), the sensitivity was 84% for neuropsychologists, 64% for cognitive neurologists and 62% for residents. The sensitivity using the complex scoring system was 92% in patients with mild AD and 69% in patients with aMCI.

CONCLUSIONS

A categorical rating of CDT shows high sensitivity for mild AD even in non-experienced raters. Neuropsychologists outperformed physicians in differentiating patients with aMCI from cognitively healthy older adults (specificity), which was counterbalanced by the lower specificity of their ratings. The diagnostic accuracy was not substantially improved by using complex scoring system. Copyright © 2016 John Wiley & Sons, Ltd.

Propositional Density in Spoken and Written Language of Czech-Speaking Patients With Mild Cognitive Impairment

PURPOSE

Propositional density (PD) is a measure of content richness in language production that declines in normal aging and more profoundly in dementia. The present study aimed to develop a PD scoring system for Czech and use it to compare PD in language productions of older people with amnestic mild cognitive impairment (aMCI) and control participants matched on age, gender, and education.

METHOD

Groups of patients with aMCI and cognitively healthy control participants (N = 20 each) provided short spoken and written language samples. Two samples were elicited for each modality, 1 describing recent events and 1 describing childhood memories. Series of neuropsychological tests were administered. The groups were compared using t-tests and the relations between measures using correlation coefficients.

RESULTS

PD was lower in spoken productions of patients with aMCI, compared with control participants, but only in language samples using remote memories. PD in these samples was related to verbal fluency and education but not to working memory. PD in written samples did not differ between participants with aMCI and control participants.

CONCLUSIONS

PD in spoken language reflects the cognitive decline in people with aMCI, but the effect is relatively mild. The results support the existing findings that PD is related to verbal fluency.

Analysis of lipophilic fluorescent products in blood of Alzheimer's disease patients

Alzheimer's disease (AD) is a severe neurodegenerative disorder characterized by cognitive decline. Prodromal stage of AD, also called mild cognitive impairment (MCI), especially its amnestic type (aMCI), precedes dementia stage of AD. There are currently no reliable diagnostic biomarkers of AD in the blood. Alzheimer's disease is accompanied by increased oxidative stress in brain, which leads to oxidative damage and accumulation of free radical reaction end‐products. In our study, specific products of lipid peroxidation in the blood of AD patients were studied. Lipophilic extracts of erythrocytes (AD dementia = 19, aMCI = 27, controls = 16) and plasma (AD dementia = 11, aMCI = 17, controls = 16) were analysed by fluorescence spectroscopy. The level of these products is significantly increased in erythrocytes and plasma of AD dementia and aMCI patients versus controls. We concluded that oxidative stress end‐products are promising new biomarkers of AD, but further detailed characterisation of these products is needed.

Clock Drawing Test and the diagnosis of amnestic mild cognitive impairment: can more detailed scoring systems do the work?

INTRODUCTION

The Clock Drawing Test is a frequently used cognitive screening test with several scoring systems in elderly populations. We compare simple and complex scoring systems and evaluate the usefulness of the combination of the Clock Drawing Test with the Mini-Mental State Examination to detect patients with mild cognitive impairment.

METHOD

Patients with amnestic mild cognitive impairment (n = 48) and age- and education-matched controls (n = 48) underwent neuropsychological examinations, including the Clock Drawing Test and the Mini-Mental State Examination. Clock drawings were scored by three blinded raters using one simple (6-point scale) and two complex (17- and 18-point scales) systems. The sensitivity and specificity of these scoring systems used alone and in combination with the Mini-Mental State Examination were determined.

RESULTS

Complex scoring systems, but not the simple scoring system, were significant predictors of the amnestic mild cognitive impairment diagnosis in logistic regression analysis. At equal levels of sensitivity (87.5%), the Mini-Mental State Examination showed higher specificity (31.3%, compared with 12.5% for the 17-point Clock Drawing Test scoring scale). The combination of Clock Drawing Test and Mini-Mental State Examination scores increased the area under the curve (0.72; p < .001) and increased specificity (43.8%), but did not increase sensitivity, which remained high (85.4%).

CONCLUSIONS

A simple 6-point scoring system for the Clock Drawing Test did not differentiate between healthy elderly and patients with amnestic mild cognitive impairment in our sample. Complex scoring systems were slightly more efficient, yet still were characterized by high rates of false-positive results. We found psychometric improvement using combined scores from the Mini-Mental State Examination and the Clock Drawing Test when complex scoring systems were used. The results of this study support the benefit of using combined scores from simple methods.

Recognition of facial emotional expression in amnestic mild cognitive impairment

We examined whether recognition of facial emotional expression would be affected in amnestic mild cognitive impairment (aMCI). A total of 50 elderly persons met the initial inclusion criteria; 10 were subsequently excluded (Geriatric Depression Score > 5). 22 subjects were classified with aMCI based on published criteria (single domain aMCI [SD-aMCI], n = 10; multiple domain aMCI [MD-aMCI], n = 12); 18 subjects were cognitively normal. All underwent standard neurological and neuropsychological evaluations as well as tests of facial emotion recognition (FER) and famous faces identification (FFI). Among normal controls, FFI was negatively correlated with Mini-Mental Status Examination scores and positively correlated with executive function. Among patients with aMCI, FER was correlated with attention/speed of processing. No other correlations were significant. In a multinomial logistic regression model adjusted for age, gender, and education, a poorer score on FER, but not on FFI, was associated with greater odds of being classified as MD-aMCI (odds ratio [OR], 3.82; 95% confidence interval [CI], 1.05-13.91; p = 0.042). This association was not explained by memory or global cognitive score. There was no association between FER or FFI and SD-aMCI (OR, 1.13; 95% CI, 0.36-3.57; p = 0.836). Therefore, FER, but not FFI, may be impaired in MD-aMCI. This implies that in MD-aMCI, the tasks of FER and FFI may involve segregated neurocognitive networks.

Balance rehabilitation therapy by tongue electrotactile biofeedback in patients with degenerative cerebellar disease

Few clinical studies have evaluated physiotherapeutic interventions in patients with degenerative cerebellar ataxia. Investigations on the effectiveness of biofeedback-based interventions for training postural control in these patients have not been conducted yet. The aim of the present study was to assess the effectiveness of a 2-week intensive tongue-placed electrotactile biofeedback program for patients with progressive cerebellar ataxia. Subjects were seven adult patients suffering from cerebellar degeneration. Postural control was assessed with static posturography in two sensory conditions eyes open/closed on firm surface. For quantification of postural behavior, we used area, sway path and mean velocity of the centre of foot pressure (CoP). Effects of treatment were determined by comparing Pre, Post and one month follow-up (Retention) experimental sessions. Analysis of measured CoP parameters for tests on firm surface showed a significant main effect of visual condition and no difference across test sessions under open eyes condition. Under eyes closed condition, there were significant differences between Pre versus Post and Pre versus Retention, while the difference Post versus Retention was not significant. Our results suggest that a balance rehabilitation program with postural exercise performed with a head position-based tongue-placed biofeedback system could significantly improve bipedal postural control in patients suffering from degenerative cerebellar ataxia.

Disturbance of real space navigation in moderately advanced but not in early Huntington's disease

BACKGROUND

Visuospatial skills including spatial navigation are known to be impaired in Huntington's disease. Spatial navigation comprises two navigational frameworks, allocentric and egocentric. Several studies have associated the allocentric navigation with the hippocampus and the egocentric navigation with the striatum. The striatum is predominantly impaired from the early stages of Huntington's disease.

OBJECTIVE

To find whether spatial navigation impairment is present in the early stages of Huntington's disease and to test the hypothesis that the egocentric navigation is predominantly affected compared to the allocentric navigation.

METHODS

In nineteen patients with Huntington's disease the egocentric and the allocentric navigation skills were tested using the Blue Velvet Arena, a human analog of Morris Water Maze, and compared to nineteen age and gender-matched healthy controls. Cognitive functions, with emphasis on the executive functions, were also assessed.

RESULTS

The spatial navigation skills deteriorated with the increasing motor impairment in Huntington's disease. These changes only became apparent in patients with moderate functional impairment. No difference between the egocentric and the allocentric skills was seen.

DISCUSSION

Spatial navigation deficit is not an early marker of the cognitive dysfunction in Huntington's disease. We speculate that the striatal circuitry that is known to degenerate early in the course of Huntington's disease is not directly associated with the spatial navigation.

Spatial navigation and APOE in amnestic mild cognitive impairment

BACKGROUND

The effect of APOE ε4 allele (ε4) on spatial navigation in amnestic mild cognitive impairment (aMCI) is unknown.

OBJECTIVE

Our purpose was to examine the characteristics of spatial navigation impairment in ε4-positive (ε4+) and ε4-negative (ε4-) aMCI subgroups.

METHODS

Blood samples were collected to determine the APOE genotype. A total of 34 aMCI patients were stratified into aMCI-ε4- (n = 23) and aMCI-ε4+ (n = 11) groups. Control (n = 28) and mild Alzheimer's disease (AD; n = 16) groups were also used. We used a human analogue of the Morris water maze (enclosed arena 2.9 m in diameter) to examine body-centered (egocentric) and world-centered (allocentric) spatial navigation.

RESULTS

The aMCI-ε4+ group performed poorer on spatial navigation than the aMCI-ε4- group in both egocentric and allocentric tasks even though these 2 groups did not differ in global cognitive functioning or neuropsychological tests. The aMCI-ε4+ and mild AD groups performed similarly on all Morris Water Maze tasks and were outperformed by the aMCI-ε4- group, which also resembled the control group in performance on the egocentric tasks. The aMCI groups showed poor spatial navigation learning regardless of their ε4 positivity.

CONCLUSION

We found more profound deficits in spatial navigation in aMCI-ε4+ relative to aMCI-ε4- patients. The aMCI-ε4+ group resembled the mild AD group in spatial navigation performance. Although the ε4 genotype was indicative of spatial navigation performance, it was not indicative of the aMCI patients' ability to learn the tasks. Spatial navigation testing represents a promising area with respect to identifying individuals at higher risk for AD among the heterogeneous MCI population.

Spatial navigation testing discriminates two types of amnestic mild cognitive impairment

The hippocampus is essential for consolidation of declarative information and spatial navigation. Alzheimer's disease (AD) diagnosis tends to be preceded by a long prodromal period and mild cognitive impairment (MCI). Our goal was to test whether amnestic MCI comprises two different subgroups, with hippocampal and non-hippocampal memory impairment, that vary with respect to spatial navigation ability. A total of 52 patients were classified into two subgroups: non-amnestic MCI (naMCI) (n=10) and amnestic MCI (aMCI) (n=42). The aMCI subgroup was further stratified into memory impairment of hippocampal type-hippocampal aMCI (HaMCI) (n=10) (potential preclinical AD) and isolated retrieval impairment-non-hippocampal (NHaMCI) (n=32). Results were compared to control (n=28) and AD (n=21) groups. We used the Hidden Goal Task, a human analogue of the Morris Water Maze, to examine spatial navigation either dependent (egocentric) or independent of individual's position (allocentric). Overall, the HaMCI group performed poorer on spatial navigation than the NHaMCI group, especially in the latter trials when the HaMCI group exhibited limited capacity to learn and the NHaMCI group exhibited a learning effect. Finally, the HaMCI group performed almost identically as the AD group. Spatial navigation deficit is particularly pronounced in individuals with hippocampus-related memory impairment and may signal preclinical AD.

Two cases of improvement of smooth pursuit eye movements after selective posterior rhizotomy

OBJECTIVE

Selective posterior rhizotomy (SPR) represents a standard neurosurgical approach in the treatment of spasticity in children with cerebral palsy (CP). Beside the reduction of spasticity in lower limbs, SPR may have suprasegmental effects, considerably above the surgery site. In this communication, we report on the improvement of smooth pursuit eye movements (SPEM) in two children after SPR.

MATERIAL AND METHODS

Four children with CP underwent SPR. Eye movements were registered by infrared video-oculography before and after the surgery.

RESULTS

The analysis of SPEM showed the improvement of the correlation coefficient of the eye response to the stimulus after SPR in two subjects. Improvement of SPEM performance was largely due to suppression of spontaneous fixation nystagmus.

CONCLUSION

SPR may lead to the improvement of SPEM in children with CP. The influence of SPEM improvement on quality of life in a group of severely disabled nonambulant children with CP remains to be assessed.

Long lasting recurrent familiar transient global amnesia after betablocker treatment withdrawal: case report

The etiology of Transient Global Amnesia (TGA) is not yet clear. A small part of TGA has a familiar occurrence. We report a case of recurrent, long-lasting familiar amnesia occurring after betablocker treatment withdrawal in a migrainous patient. We suggest that familiar TGA could be caused by the mechanism of vasospasm rather than venous congestion and that the abnormal cerebral vasomotor control could be the hereditary substrate in this condition.

Spatial navigation deficit in amnestic mild cognitive impairment

Patients with Alzheimer's disease (AD) frequently have difficulties with spatial orientation in their day-to-day life. Although AD is typically preceded by amnestic mild cognitive impairment (MCI), spatial navigation has not yet been studied in MCI. Sixty-five patients were divided into five groups: probable AD (n = 21); MCI, further classified as amnestic MCI single domain (n = 11); amnestic MCI multiple domain (n = 18), or nonamnestic MCI (n = 7), and subjective memory complaints (n = 8). These patients, together with a group of healthy control subjects (n = 26), were tested by using a four-subtests task that required them to locate an invisible goal inside a circular arena. Each subtest began with an overhead view of the arena showed on a computer monitor. This was followed by a real navigation inside of the actual space, an enclosed arena 2.9 m in diameter. Depending on the subtest, the subjects could use the starting position and/or cues on the wall for navigation. The subtests thus were focused on allocentric and egocentric navigation. The AD group and amnestic MCI multiple-domain group were impaired in all subtests. The amnestic MCI single-domain group was impaired significantly in subtests focused on allocentric orientation and at the beginning of the real space egocentric subtest, suggesting impaired memory for allocentric and real space configurations. Our results suggest that spatial navigation impairment occurs early in the development of AD and can be used for monitoring of the disease progression or for evaluation of presymptomiatic AD.

School children dyslexia analysis using self organizing maps

The main goal of the study is an unsupervised classification of school children dyslexia. Eye movements of 49 subjects were measured using videooculographic technique (VOG) during two non-reading and one reading tasks. A feature selection was performed obtaining data set consisting of 26 features. Next an inductive modelling technique was applied to data set resulting in extraction of six features which were used as the input to self-organizing map (SOM). Three clusters were finally formed by the SOM proving that the proposed methodology is suitable for automatic dyslexia analysis.

Novel EGR2 mutation R359Q is associated with CMT type 1 and progressive scoliosis

Mutations in the early growth response 2 gene (EGR2) cause demyelinating neuropathies differing in severity and age of onset. We tested 46 unrelated Czech patients with dominant or sporadic demyelinating CMT neuropathy for mutations in the EGR2 gene. One novel de-novo mutation (Arg359Gln, R359Q) was identified in heterozygous state in a patient with a typical CMT1 phenotype, progressive moderate thoracolumbar scoliosis and without clinical signs of cranial nerve dysfunction. This patient is presently less affected compared to previously described Dejerine-Sottas neuropathy (DSN) patients carrying another substitution at codon 359 (Arg359Trp, R359W). This report shows that EGR2 mutations are rare in Czech patients with demyelinating type of CMT and suggests that different substitutions at codon 359 of EGR2 can cause significantly different phenotypes.

Concomitancy of mutation in FRDA gene and FMR1 premutation in 58 year-old woman

DNA testing broadens diagnostic tools available for hereditary ataxias. However, together with current knowledge of genes and their mutations crop up new phenotype figures of diseases already well known. Diagnostic problems in practice can consist in part due to the very similar symptoms of hereditary ataxias and acquaintance in or availability of new techniques such as DNA testing and result in misdiagnosis. We present a case study of a 57 year-old woman with both expansion of the triplet repetitive sequence of FRDA gene and a premutation in FMR1 gene. At present we diagnose her with Very Late Onset Friedreich s ataxia, but we advise of possible combinations or aggravations of her symptoms due to manifestation of Fragile X premutation tremor/ataxia syndrome. In nontypical phenotypes of DNA verifying hereditary ataxias we recommend searching of comorbidity, specifically from a range of hereditary ataxias with very similar spectra of symptoms.