The Effects of Type 2 Diabetes on Cognitive Performance: A Review of Reviews.

BACKGROUND: Multiple systematic reviews have found that type 2 diabetes is associated with cognitive decrements. However, these reviews are heterogeneous in terms of methodology, quality and results, making it difficult for researchers and clinicians to build an informed overall picture. We therefore conducted a review of systematic reviews on the association between type 2 diabetes and cognitive decrements in relation to healthy controls. METHODS: Following a pre-registered research protocol, we searched four major databases. Nine systematic reviews met our inclusion criteria: seven were meta-analyses and two were narrative syntheses. We assessed the risk of bias in each review and reported all effect sizes and confidence intervals obtained. RESULTS: Type 2 diabetes was associated with cognitive decrements in all reviews, with small or negligible effect sizes obtained in the largest meta-analyses. The most studied cognitive domains were attention, executive functions, memory, processing speed and working memory. All reviews had methodological issues and were rated as having a high or an unclear risk of bias. CONCLUSIONS: Type 2 diabetes appears to be associated with lower cognitive performance in several cognitive domains and in different age groups. However, high-quality meta-analyses on the subject are still needed. Future reviews must follow the PRISMA guidelines and take into account the risk of bias of the original studies through sensitivity analyses and the heterogeneity of the studies by conducting subgroup analyses for example according to age group and disease duration. The meta-analyses that aim to study the entire type 2 diabetes population without excluding severe comorbidities, should assess concept formation and reasoning, construction and motor performance, perception, and verbal functions and language skills in addition to the cognitive domains that have been most frequently analysed in the reviews conducted so far.

Type 2 diabetes and cognitive performance in middle age: a cross-sectional study.

INTRODUCTION: Type 2 diabetes has been associated with cognitive decrements already in middle-age. However, the sample sizes of the studies have been small and the neuropsychological tests used have been heterogeneous. In addition, only a few studies have matched the groups in terms of age, education and gender. In this cross-sectional matched pairs study, we investigated the cognitive performance of Finnish middle-aged type 2 diabetes patients compared to healthy individuals. METHOD: A neuropsychological test battery consisting of 16 tests and 21 outcome measures was applied to 28 patients and 28 age-, education- and gender-matched healthy individuals. Various exclusion criteria were applied to minimize the risk of cognitive dysfunction due to factors other than diabetes. RESULTS: We did not find between-group differences in any of the neuropsychological tests measuring attention, concept formation and reasoning, construction and motor performance, executive functions, memory, processing speed or working memory. In addition, there were no group differences in the frequency or severity of subjective cognitive symptoms, or in anxiety, depression, burnout, fatigue or alcohol use disorder symptoms. The effect sizes in this study were mostly negligible or small, with the mean effect size being -0.12. CONCLUSIONS: In a carefully matched sample of middle-aged type 2 diabetes patients and healthy individuals, we found no significant effects and no meaningful evidence of cognitive differences between the groups.

Apraxia and dementia severity in Alzheimer's disease: a systematic review.

INTRODUCTION: To investigate the role and influence of apraxia regarding dementia severity in Alzheimer's disease (AD). In addition, to examine whether apraxia or its association to dementia severity show distinct characteristics between typical and atypical variants of AD, that commonly include frontal, logopenic, posterior, and Down's syndrome variant. METHOD: The search conducted on 4 December 2020 in the Cinahl, Ovid Medline, PsycArticles, PsycInfo, Scopus and Web of Science databases yielded 251 non-duplicate records published since 2000. Ten records examining the association between Clinical Dementia Rating (CDR) scores and apraxia in AD were included in the review. RESULTS: Dementia severity was related to apraxia in AD, and the prevalence and severity of apraxia increased as dementia progressed. Constructional, ideomotor (imitation of meaningless gestures), orofacial, speech, gait, and total praxis, including constructional, ideomotor, and ideational praxis, tasks differentiated dementia severity in AD. In the atypical variants of AD apraxia occurred frequently but because of the small number of participants, no statistical analyses were available. CONCLUSIONS: The results highlight the need for extensive assessment of AD severity, and praxis assessment throughout the disease course. Apraxia affects the independent functioning and communication of the patient, tool use, and the ability to perform activities of daily living. Apraxia occurs frequently in AD and other neurodegenerative diseases, and apraxia assessment has shown to differentiate AD from other neurodegenerative diseases, particularly frontotemporal dementia. Thus, apraxia assessment serves in recognizing the atypical variants of AD as well.

Apraxia testing to distinguish early Alzheimer's disease from psychiatric causes of cognitive impairment.

Objective: Mood- and stress-related disorders commonly cause attentional and memory impairments in middle-aged individuals. In memory testing, these impairments can be mistakenly interpreted as symptoms of dementia; thus, more reliable diagnostic approaches are needed. The present work defines the discriminant accuracy of the Dementia Apraxia Test (DATE) between psychiatric conditions and early-onset Alzheimer's disease (AD) on its own and in combination with memory tests. Method: The consecutive sample included 50-70-year-old patients referred to dementia investigations for recent cognitive and/or affective symptoms. The DATE was administered and scored as a blinded measurement, and a receiver operating curve analysis was used to define the optimal diagnostic cut-off score. Results: A total of 24 patients were diagnosed with probable AD (mean age 61 ± 4) and 23 with a psychiatric condition (mean age 57 ± 4). The AD patients showed remarkable limb apraxia, but the psychiatric patients mainly performed at a healthy level on the DATE. The test showed a total discriminant accuracy of 87% for a total sum cut-off of 47 (sensitivity 79% and specificity 96%). The limb subscale alone reached an accuracy of 91% for a cut-off of 20 (sensitivity 83% and specificity 100%). All memory tests were diagnostically less accurate, while the combination of the limb praxis subscale and a verbal episodic memory test suggested a correct diagnosis in all but one patient. Conclusions: Apraxia testing may improve the accuracy of differentiation between AD and psychiatric aetiologies. Its potential in severe and chronic psychiatric conditions should be examined in the future.

The dementia apraxia test can detect early-onset Alzheimer's disease.

OBJECTIVE: Limb apraxia is a common early sign of Alzheimer's disease (AD) and is thought to occur specifically in early-onset (before the age of 65) AD. The Dementia Apraxia Test (DATE), a test of limb and face praxis developed to support the differential diagnosis of dementia, has shown good diagnostic accuracy in detecting AD in older patients, but it has not been validated for younger age groups. We investigated how accurately DATE can detect AD in middle-aged individuals and whether apraxia is a distinctive feature in early-onset AD. METHOD: A sample of mild-stage AD patients (n = 24; Mage = 61, SD = 4) was drawn from a prospective consecutive series of individuals referred to our neurology clinic for dementia investigations. A healthy comparison group (HC) of comparable age (n = 22; Mage = 61, SD = 7), sex distribution, and education was recruited. DATE was administered as a blinded experimental measure, and a receiver operating characteristic (ROC) analysis was used to define the optimal diagnostic cutoff point. RESULTS: The DATE classified 93% of the participants correctly as AD or HC (sensitivity 0.88, specificity 1.00, area under curve 0.968). The optimal diagnostic cutoff point was higher (49 points) than in a previous sample of older patients (45 points). Early onset did not seem to be associated with worse praxis performance in AD. CONCLUSIONS: DATE is an accurate tool for detecting early-onset AD within 2 years of symptom onset. The diagnostic cutoff point should be higher for middle-aged populations than for late-onset AD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Neuropsychological findings in migraine: a systematic review / Achados neuropsicológicos na enxaqueca: uma revisão sistemática

ABSTRACT. Patients with migraine often experience cognitive dysfunction during a migraine attack, but they have also been reported to complain about cognitive impairment after an attack and during the interictal period. Objective: The aim of this study was to determine what neuropsychological test methods are used to assess cognitive functioning in migraine patients and to examine the neuropsychological findings in adult (≥18 years) migraineurs compared to adult (≥18 years) healthy controls (HC). Methods: A systematic review was conducted on the literature published between 2012 and the present. The search results were screened and additional studies identified in the lists of references in the selected articles. A total of 16 articles met the inclusion criteria. Results: The 16 articles included in the review compared chronic migraineurs (CM), migraineurs with (MwA) and without aura (MwoA), and migraineurs without aura classification (MIG) to HC. A total of 45 neuropsychological assessment methods were identified. CM and MwA were found to perform significantly worse than HC in executive function, attention, and visual functioning. Additionally, both MwA and MwoA performed significantly worse than HC in memory functions. CM and both MwA and MwoA also performed significantly worse than HC in general cognitive functioning. Surprisingly, MIG performed significantly better than HC in several cognitive domains, including executive, motor, and language functioning and general cognitive functioning. Conclusions: This systematic review mostly concurs with the results of an earlier systematic review on the topic from 2012, but with the important addition that different migraine diagnostic groups should be assessed separately.

RESUMO: Pacientes com enxaqueca frequentemente apresentam disfunção cognitiva durante uma crise, mas também foram relatadas queixas de comprometimento cognitivo após uma crise e durante o período interictal. Objetivo: Determinar quais métodos de testes neuropsicológicos são usados para avaliar o funcionamento cognitivo em pacientes com enxaqueca e examinar os achados neuropsicológicos em adultos (≥ 18 anos) com enxaqueca em comparação com adultos (≥ 18 anos) controles saudáveis (CS). Métodos: Foi realizada uma revisão sistemática da literatura publicada entre 2012 e o presente. Os resultados da pesquisa foram selecionados e estudos adicionais identificados nas listas de referências nos artigos selecionados. Dezesseis artigos preencheram os critérios de inclusão. Resultados: Os 16 artigos incluídos na revisão compararam enxaqueca crônica (EC), enxaqueca com (EcA) e sem aura (EsA), e enxaqueca sem classificação de aura (E) em CS. Foram identificados 45 métodos de avaliação neuropsicológica. Indivíduos com EC e EcA apresentaram desempenho significativamente pior do que CS em função executiva, atenção e funcionamento visual. Além disso, tanto a EcA quanto a EsA tiveram desempenho significativamente pior do que em CS nas funções de memória. A EC, a EcA e a EsA também tiveram desempenho significativamente pior do que CS no funcionamento cognitivo geral. Surpreendentemente, a E teve um desempenho significativamente melhor do que os CS em vários domínios cognitivos, incluindo o funcionamento executivo, motor e de linguagem e o funcionamento cognitivo geral. Conclusões: Esta revisão sistemática concorda principalmente com os resultados de uma revisão sistemática anterior sobre o tema de 2012, mas com o importante adendo de que diferentes grupos diagnósticos de enxaqueca devem ser avaliados separadamente.

Limb and face apraxias in frontotemporal dementia: A systematic scoping review.

PURPOSE: To investigate the literature for frequencies, profiles and neural correlates of limb and face apraxias in frontotemporal dementia (FTD). METHOD: The search conducted in Ovid Medline, PsycINFO and Scopus yielded 487 non-duplicate records, and 43 were included in the final analysis. RESULTS: Apraxias are evident in diverse forms in all clinical variants of FTD within the first four years of the disease. Face apraxia and productive limb apraxia co-occur in the behavioural and nonfluent variants. The logopenic variant resembles Alzheimer's disease in terms of pronounced parietal limb apraxia and absence of face apraxia. The semantic variant exhibits conceptual praxis deficits together with relatively preserved imitation skills. Concerning the genetic variants of FTD, productive limb apraxia is common among carriers of the progranulin gene mutation, and subtle gestural alterations have been documented among carriers of the chromosome 9 open reading frame 72 gene mutation before the expected disease onset. The data on neural correlations suggest that the breakdown of praxis results from bilateral cortical and subcortical damage in FTD and that Alzheimer-type pathology of the cerebrospinal fluid increases the severity of limb apraxia in all of the variants. Face apraxia correlates with degeneration of the medial and superior frontal cortices. CONCLUSIONS: Each of the clinical variants of FTD exhibits a characteristic profile of apraxias that may support early differentiation between the variants and from Alzheimer's disease. However, the screening procedures developed for stroke populations seem insufficient, and a multifaceted assessment tool is needed. Although valid and practical tests already exist for dementia populations, a concise selection of test items that covers all of the critical domains is called for.

Type 2 Diabetes and Cognitive Functions in Middle Age: A Meta-Analysis.

Objectives: Type 2 diabetes mellitus has been linked with cognitive decrement and an increased risk of dementia in older people. Less is known about whether diabetes affects cognition at younger ages. The objective of this meta-analysis was to examine possible differences (effect sizes) in cognitive performance between middle-aged type 2 diabetic patients and healthy controls. Secondary aim was to examine whether age is related to the magnitude of effect sizes. Methods: Electronic databases and lists of references of selected articles were used to search for studies examining type 2 diabetes and cognition in patients under age 65 compared to healthy controls. Twelve studies met the inclusion criteria. Standardized mean differences (Hedges's g) were calculated for main cognitive domains and their subdomains. Association between age and effect sizes was evaluated with meta-regression analyses. Publication bias and methodological quality of the studies were assessed. Results: Patients performed worse than controls in several cognitive functions. The largest differences were found in information processing speed (g = -0.68), attention/concentration (g = -0.55), executive functions (g = -0.51), and working memory (g = -0.51). There was no significance difference in visual memory (g = -0.15). Age was significantly related to the effect size in information processing speed, language, verbal memory and visual memory. However, the direction of association varied across these cognitive domains. Conclusions: The results suggest that cognitive decrement in diabetes is not restricted to older people, but may begin to appear in middle age. More attention should be paid to early recognition and treatment of diabetes-related cognitive decrement in healthcare systems. (JINS, 2019, 25, 215-229).

The 'Neglected' Personal Neglect.

A review of patients with brain injury showing personal neglect is presented. The aim is to shed light on this aspect of neglect often unresearched or only indirectly investigated, and to discuss recent findings concerning the methods used to assess personal neglect, its neural correlates and its association with the more often explored aspect of extrapersonal neglect. The review was performed using PubMed and PsychInfo databases to search for papers published in the last 123 years (until January 2018). We reviewed 81 papers describing either single or group studies for a total of 2247 patients. The results of this review showed that various aspects of personal neglect are still controversial and outcomes potentially contradictory. Despite the data reported in the present review suggest that personal neglect is more frequently associated with lesions of the right hemisphere, the left hemisphere may also play an important role. Not surprisingly, personal neglect and extrapersonal neglect seem to co-occur. However double dissociations of these two forms of neglect have been reported, and they seem to dissociate both from a functional and an anatomical perspective. More recent interpretations of personal neglect suggest that it may result from a disrupted body representation. The development of reliable psychometric tools with shared diagnostic criteria is essential to identify different degrees of personal neglect for different body parts and to better refine personal neglect in comparison to extrapersonal neglect and disorders related to distortions of personal domain.

Occurrence and Recovery of Different Neglect-Related Symptoms in Right Hemisphere Infarct Patients during a 1-Year Follow-Up.

OBJECTIVES: To examine the occurrence of and recovery from visual neglect-related symptoms with the focus on neglect laterality, ipsilateral orienting bias, and slowed processing speed in right hemisphere (RH) infarct patients during a 1-year follow-up. Furthermore, to propose guidelines for assessing processing speed alongside the Behavioural Inattention Test (BIT). METHODS: We studied three RH patient groups: neglect (N+), mild left inattention (MLI+), and non-neglect (N-) patients, and healthy controls. The BIT with some additional analyses was conducted at the acute phase and at 6 and 12 months. RESULTS: The N+ group's BIT score increased and originally lateralized omissions became more evenly distributed during the follow-up. The N+ and MLI+ groups' starting points were more rightward located than the healthy group's at the acute phase and at 6, and partly at 12 months. Patient groups were slower than the controls in performing cancellation tests at the acute phase. The N+ and MLI+ groups remained slower than the controls throughout the follow-up. CONCLUSIONS: During the first year after RH infarct, originally left-sided manifestation of neglect shifted toward milder non-lateralized attentional deficit. Ipsilateral orienting bias and slowed processing speed appeared to be rather persistent neglect-related symptoms both in neglect patients and patients with initially milder inattention. We propose some effortless, tentative ways of examining processing speed and ipsilateral orienting bias alongside the BIT to better recognize these neglect-related symptoms, and highlight the need to assess and treat patients with initially milder inattention, who have been under-recognized and under-treated in clinical work. (JINS, 2018, 24, 617-628).

Factors Influencing Quality of Life Six Months after a First-Ever Ischemic Stroke: Focus on Thrombolyzed Patients.

OBJECTIVE: This prospective follow-up study aimed to identify sociodemographic and clinical factors that may affect the quality of life (QoL) of patients with acute ischemic stroke during a 6-month follow-up. PATIENTS AND METHODS: In the acute phase, sociodemographic and clinical data were collected using the National Institute of Health Stroke Scale, Barthel Index, and modified Rankin Scale. QoL was assessed with the Stroke and Aphasia Quality of Life Scale-39 6 months after stroke. RESULTS: QoL was evaluated in 64 patients (aged 45-81 years) with a first-ever ischemic stroke. Thrombolytic therapy was given to 80% of the patients. Stroke severity, dependence in activities of daily living, degree of handicap, and length of hospitalization were associated with QoL. QoL was not associated with age, gender, marital status, or years of education. CONCLUSION: In this study, most patients were treated with thrombolysis, and QoL results resembled those of earlier studies on patients without thrombolysis. Despite good physical recovery, the patients reported impairments in QoL. QoL assessments can give clinicians a more holistic picture of stroke recovery from the patient's perspective.

[Recognition and rehabilitation of impaired awareness of illness, i.e. anosognosia in a patient with cerebrovascular disease]. / Aivoverenkiertohäiriöpotilaan oiretiedostuksen puutteellisuuden eli anosognosian tunnistaminen ja kuntoutus.

The prevalence of anosognosia after stroke is approximately 30%. Anosognosia refers to the lack of awareness of illness or specific symptom of illness in patients with neurological diseases. Because stroke patients with anosognosia are not properly comprehending the nature of their medical situation, they may not seek treatment in time, which weakens patients' commitment to treatment and rehabilitation. Anosognosia also exposes patients to dangerous situations in daily life. Anosognosia is associated with poor functional outcome after stroke, which makes the early neuropsychological identification and treatment of anosognosia important.

Assessing anosognosias after stroke: a review of the methods used and developed over the past 35 years.

This review provides an overview of research into anosognosia after stroke over the past 35 years. We are specifically interested in the assessment of anosognosia in group studies and in how any changes in assessment procedures have impacted the study of anognosia. Our work is based on a systematic review of reports drawn from electronic databases covering the period from 1978 to 2013 (CINAHL, PubMedMEDLINE, PsycINFO, Web of Knowledge). Sixty-four articles met the selection criteria. The results of our review show that a deeper understanding has evolved of the multifaceted syndrome of anosognosia during the past decade. The most recent studies made more extensive use of research, observational and performance-based procedures as well as traditional interview methods. Modality specificities and patients with language impairment also receive closer consideration than earlier. Furthermore, the results are more often obtained from homogeneous patient groups. The limitations of recent anosognosia research include the diversity of assessment methods used and the variation in the assessment times between and within patient groups, and the tendency to rely on only 1 method to assess and diagnose anosognosia. In order to improve the comparability of anosognosia studies it would be useful to have guidelines for the number and type of assessment methods used in studying different subtypes of anosognosia, and to focus on homogeneous patient samples. Furthermore, it is recommended that more research be done to explore chronic anosognosia and its impact on daily living.

[Neglect rehabilitation after stroke]. / Neglect-oire aivoverenkierron häiriön jälkeen--potilaan neuropsykologinen kuntoutus.

Neglect is a common neuropsychological disorder after right hemisphere stroke. Neglect worsens the prognosis of functional recovery but responds well to targeted neuropsychological rehabilitation. Several methods for rehabilitation have been developed and research to-date lends best support to visual scanning training, prism adaptation, limb activation and feedback training. Core features of effective neglect rehabilitation include early initiation, daily held sessions at acute and subacute stages, increasing awareness of deficit and considering the psychosocial status of the patient as well as that of the family.

Reliability, validity and clinical usefulness of the BNI fatigue scale in mild traumatic brain injury.

OBJECTIVES: The purpose of this study was to examine the reliability, validity and clinical usefulness of the Barrow Neurological Institute Fatigue Scale (BNI-FS) in patients with mild traumatic brain injuries (MTBI). METHODS AND PROCEDURE: Participants were 125 patients enrolled from the Emergency Department (ED) of Tampere University Hospital, Finland who had sustained an MTBI. The average number of days from injury to the interview and questionnaires was 24.1 (SD = 5.4, Range = 8-38). The patients were compared to a healthy control sample. Patients completed the Barrow Neurological Institute Fatigue Scale, Fatigue Impact Scale (FIS), Beck Depression Inventory-Second Edition (BDI-II), Rivermead Post-concussion Symptom Questionnaire (RPSQ) and the health assessment measure EuroQol five Dimension (EQ-5D) Visual Analogue Scale (VAS). RESULTS: The MTBI group had significantly greater total scores on the BNI-FS than the control group (p < 0.005, Cohen's d = 0.40). The internal consistency reliability for the BNI-FS, as measured by Cronbach's alpha, was 0.96 for the MTBI group and 0.87 for the control group. The 10 items were submitted to an exploratory principal components factor analysis with varimax rotation in the MTBI group. A one-factor solution, accounting for 73.3% of the total variance, appropriately summarized the data. The correlation between the BNI-FS and other measures was rs = 0.68 (p < 0.001) for the BDI-II, rs = 0.68 (p < 0.001) for the RPSQ, rs = -0.39 (p < 0.001) for the EQ-5D VAS and rs = 0.84 (p < 0.001) for the FIS. Fatigue ratings correlated positively with number of days post-injury before returning to work (rs = 0.27, p < 0.006). CONCLUSION: The BNI-FS is a relatively new, brief and highly reliable measure of fatigue.

Driving ability in stroke patients with residual visual inattention: a case study.

Driving ability of three patients having a right hemisphere infarct and residual visual inattention was examined. The neuropsychological examination included the Peripheral Perception Test and the Signal Detection Test from the Vienna Test System, and the Behavioural Inattention Test (BIT). Driving ability was assessed with an on-road evaluation. The patients had no neglect based on the BIT and had normal visual fields, but they showed slightly poorer visual search on the left side. All patients passed the official on-road driving test and were considered capable of driving. This study raises the question if acute neglect can recover to a degree in which driving may be possible.

Thrombolytic therapy and visuoperceptual functions in right hemisphere infarct patients.

This study examines the association between thrombolysis and visuoperceptual functions in right hemisphere (RH) infarct patients. Fifty-six consecutive patients with first acute RH infarct were matched for age, years of education and stroke severity at the time of admission to the emergency department (baseline NIHSS; National Institute of Health Stroke Scale), compared according to whether (T+) or not (T-) they received thrombolysis. Neurological (NIHSS at hospital ward; Barthel index; BI) and neuropsychological examinations were conducted 4 days after onset. Visuoconstructive abilities were assessed with the block design and visual search and reasoning with the picture completion subtests of the Wechsler Adult Intelligence Scale revised. Visual neglect was assessed with the conventional subtests of the Behavioural Inattention test and visual memory with the visual reproduction subtest of the Wechsler Memory Scale Revised. T+ and T- patients did not differ in baseline NIHSS, age, years of education, hemianopia, hemiparesis, or in basic ADL (BI). T- patients had more severe strokes (NIHSS at hospital ward) and poorer visuoconstructive abilities than T+ patients. Our results indicate that thrombolysis has a favourable effect on visuoperceptual functions in acute stroke.

Right hemisphere infarct patients and healthy controls: evaluation of starting points in cancellation tasks.

Patients with visual neglect (VN) tend to start cancellation tasks from the right. This exceptional initial rightward bias is also seen in some right hemisphere (RH) stroke patients who do not meet the criteria of VN in conventional tests. The present study compared RH infarct patients' (examined on average 4 days post-stroke) and healthy controls' starting points (SPs) in three cancellation tasks of the Behavioural Inattention Test (BIT). Furthermore, task-specific guideline values were defined for a normal SP to differentiate the performance of healthy subjects from that of patients with subclinical inattention. Conventional tests indicated that 15 of the 70 RH infarct patients had VN. The control group comprised 44 healthy volunteers. In each task, the VN group started the cancellations mainly from the right. The non-neglect and healthy groups initiated most cancellations from the left, more so in the healthy group. Starting more than one BIT task outside the guideline value indicated pathological inattention, as this was typical among the VN patients, but exceptional among the healthy subjects. One-third of the non-neglect patients showed pathological inattention by starting more than one task outside the guideline value. Clinical assessment of VN should, therefore, include an evaluation of the SPs to detect this subtle form of neglect.

Executive dysfunction and learning effect after continuous positive airway pressure treatment in patients with obstructive sleep apnea syndrome.

AIMS: To assess the impact of continuous positive airway pressure (CPAP) treatment on executive dysfunction in patients with obstructive sleep apnea syndrome (OSAS). METHODS: At baseline, 20 OSAS patients and 17 healthy controls underwent polysomnography and neuropsychological assessment focusing on executive functions. After at least 6 months of CPAP treatment, the patients returned for one more full-night polysomnography and neuropsychological control assessment, while the controls underwent a neuropsychological control assessment. RESULTS: All patients and controls were working-age males. OSAS severity ranged from mild to severe. Before CPAP, patients showed poorer performance than controls in the copy of the Rey-Osterrieth Complex Figure Test, the Block Design, the Digit Symbol, the Trails B and the Intra-Extra Dimensional Set-Shifting task. Patients' executive performance showed no improvement after CPAP, and it remained poorer than the performance of controls. In addition, patients showed no learning effect in the executive tests, whereas the controls did. CONCLUSION: Even long-term CPAP treatment does not seem to improve OSAS patients' mental set-shifting performance or their visuospatial organizational skills. In addition, OSAS patients have impaired learning effect in executive tests.

Visual dysfunction and computational sleep depth changes in obstructive sleep apnea syndrome.

The aims of this study are to clarify whether patients with obstructive sleep apnea syndrome (OSAS) have a decline in verbally or visually-based cognitive abilities and whether the possible decline is related to particular sleep depth changes. In addition, the effect of continuous positive airway pressure (CPAP) on the possible changes is investigated. Fifteen OSAS patients and 15 healthy controls joined two full-night polysomnographies, including a computational measure of deep sleep percentage (DS%) bilaterally from the frontal, central and occipital channels, and a neuropsychological assessment. After a 6-month CPAP the patients underwent one more full-night polysomnography with computational DS% analysis and a neuropsychological assessment. At the baseline, the OSAS patients had poorer performance in the Picture Completion, in the Digit Symbol and in copying the Rey-Osterrieth Complex Figure Test (ROCFT) compared to the controls. The patients also showed reduced DS% in all 6 electrographic (EEG) channels compared to controls. The patients had an inter-hemispheric difference showing less deep sleep in the right hemisphere than in the left hemisphere both frontopolarly and centrally, while the controls showed this inter-hemispheric difference only frontopolarly. After CPAP the patients still had poorer performance in the Picture Completion and in the ROCFT. The patients continued to show reduced DS% in all 3 channels of the right hemisphere and occipitally in the left hemisphere, also the inter-hemispheric difference frontopolarly and centrally remained. OSAS patients have mild visually based cognitive dysfunction and reduced amount of deep sleep in the right hemisphere even after CPAP.