Neuropsychiatric symptoms and their neural correlates in individuals with mild cognitive impairment.

OBJECTIVES: Neuropsychiatric symptoms are common in subjects with MCI and associated with higher risk of progression to AD. The cognitive and neuroanatomical correlates of neuropsychiatric symptoms in MCI have not been fully elucidated. In this study, we sought to evaluate the association between neuropsychiatric symptoms, cognitive function, regional tau deposition, and brain volumes in MCI subjects. METHODS: A total of 233 MCI and 305 healthy comparisons were selected from the ADNI-3 cohort. All the subjects underwent a comprehensive neuropsychological assessment, volumetric MR brain scan, and Flortaucipir PET for in vivo assessment of regional tau deposition. Prevalence of neuropsychiatric symptoms was evaluated by means of the NPI questionnaire. Multivariate analyses of variance were used to detect differences in cognitive and imaging markers in MCI subjects with and without neuropsychiatric symptoms. RESULTS: 61.4% MCI subjects showed at least one neuropsychiatric symptom, with the most prevalent ones being depression (26.1%), irritability (23.6%), and sleep disturbances (23.6%). There was a significant effect of neuropsychiatric symptoms on cognitive tests of frontal and executive functions. MCI subjects with neuropsychiatric symptoms showed reduced brain volumes in the orbitofrontal and posterior cingulate cortices, while no effects were detected on regional tau deposition. Posterior cingulate cortex volume was the only predictor of global neuropsychiatric burden in this MCI population. CONCLUSIONS: Neuropsychiatric symptoms occur early in the AD trajectory and are mainly related to defects of control executive abilities and to the reduction of gray matter volume in the orbitofrontal and posterior cingulate cortices. A better understanding of the cognitive and neuroanatomical mechanisms of neuropsychiatric symptoms in MCI could help develop more targeted and efficacious treatment alternatives.

From aMCI to AD: The Role of Visuo-Spatial Memory Span and Executive Functions in Egocentric and Allocentric Spatial Impairments.

A difficulty in encoding spatial information in an egocentric (i.e., body-to-object) and especially allocentric (i.e., object-to-object) manner, and impairments in executive function (EF) are typical in amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Since executive functions are involved in spatial encodings, it is important to understand the extent of their reciprocal or selective impairment. To this end, AD patients, aMCI and healthy elderly people had to provide egocentric (What object was closest to you?) and allocentric (What object was closest to object X?) judgments about memorized objects. Participants' frontal functions, attentional resources and visual-spatial memory were assessed with the Frontal Assessment Battery (FAB), the Trail Making Test (TMT) and the Corsi Block Tapping Test (forward/backward). Results showed that ADs performed worse than all others in all tasks but did not differ from aMCIs in allocentric judgments and Corsi forward. Regression analyses showed, although to different degrees in the three groups, a link between attentional resources, visuo-spatial memory and egocentric performance, and between frontal resources and allocentric performance. Therefore, visuo-spatial memory, especially when it involves allocentric frames and requires demanding active processing, should be carefully assessed to reveal early signs of conversion from aMCI to AD.

Executive functioning profiles in elite volleyball athletes: Preliminary results by a sport-specific task switching protocol.

Executive functions (EF) are crucial for the athletes' success, and they are even more essential in open skill sports (e.g. volleyball and football). In these sports, due to continuously changing conditions, goal-directed behaviours need to be repeatedly adjusted and corrected. One of the most important EF is the ability to continuously switch between two different tasks being required in a random sequence. We used a task-switching protocol in elite volleyball athletes, usually playing different roles, with the aim of evaluating if each role is characterized by specific switching abilities. On the basis of the specific competences requested by the game, thirty-six elite volleyball athletes were assigned to three groups: Strikers, Defenders and Mixed. Each player completed a customized sport-specific task-switching paradigm. Data evidenced that each role has specific characteristics. In Reaction Times, the Strikers were the fastest to answer to stimuli, while the Defender group provided a worse performance, particularly when defensive actions, that probably require more cognitive elaboration, had to be processed. Different effects emerged by the Errors. In fact, the Mixed group, which was the one with more expertise, appeared to be more accurate in the responses. Although preliminary, these results showed a minimal degree of cognitive flexibility for highly specialized Strikers and a maximum level for Mixed, allowing thus to highlight specific profiles of athletes. Data observed indicate the possibility to develop a test assessing the executive domain during the recruitment in a team, revealing a useful tool for choosing the most suitable role.

Cognitive dysfunctions in occipital lobe epilepsy compared to temporal lobe epilepsy.

OBJECTIVE: To compare cognitive profiles of occipital lobe epilepsy (OLE) and temporal lobe epilepsy (TLE) and to investigate whether impairment of visuospatial functions is a specific deficit of OLE. METHOD: Eighteen patients with OLE, 18 patients with TLE, and 18 controls underwent a neuropsychological battery assessing memory, visuospatial functions, and frontal/executive functions. RESULTS: Multivariate analysis evidenced poorer performance of patients with TLE and patients with OLE relative to controls on tasks assessing verbal and non-verbal long-term memory, frontal functions, and visuospatial functions. Patients with OLE had poorer performance than patients with TLE on visuospatial tasks, whereas patients with TLE performed worse than patients with OLE on verbal long-term memory test. Discriminant analysis identified two canonical discriminant functions: The first explained 53.3% of the variance, and the second explained 46.7% of the variance. The first function included verbal and non-verbal memory tests distinguishing controls from both OLE and TLE, whereas the second factor including a visuoconstructional test distinguished OLE from TLE and controls. CONCLUSIONS: The results demonstrate that visuoconstructional dysfunction is related to OLE and support the idea that alterations of occipito-parietal stream may be specific to patients with OLE.

Virtual Kitchen Test. Assessing frontal lobe functions in patients with alcohol dependence syndrome.

INTRODUCTION: This article is part of the Focus Theme of Methods of Information in Medicine on "New Methodologies for Patients Rehabilitation". BACKGROUND: The ecological validity of paper-and-pencil neuropsychological tests is currently a matter of debate. Arguments in favor of alternatives indicate that paper-and-pencil forms are unable to account for both mental and functional aspects of cognitive functioning. OBJECTIVES: In this study we developed a new neuropsychological evaluation test - the Virtual Kitchen Test (VKT) - devised to evaluate frontal brain functioning in cognitively impaired individuals. We designed this test according to the rationale of the Trail Making Test (TMT), in order to capture frontal lobe abilities during a more ecologically valid task. METHODS: Forty-nine participants, 25 from a clinical sample of patients diagnosed with Alcohol Dependence Syndrome, plus 24 healthy participants. RESULTS: Execution errors and task completion time were significantly higher in the clinical sample. Also, scores on the new VKT showed moderate to high positive correlations with scores on the TMT. Furthermore, the overall discriminant performance of the VKT was high for both of its indicators. CONCLUSIONS: Overall results support the ability of the VKT to evaluate frontal lobe functions. The best cut-off scores based on this sample are discussed.

Age-related difference in relationships between cognitive processing speed and general cognitive status.

General cognitive status (GCS) is a composite of cognitive abilities reflecting full function. The literature suggests a relationship between cognitive processing speed and GCS, as well as age-related changes of processing speed on cognitive performance. Therefore, this study recruited 34 younger and 39 older adults to verify age-related differences in relationships between cognitive processing speed and GCS. We measured cognitive processing speed with the Processing Speed Index of the Wechsler Adult Intelligence Scale. Findings indicated that cognitive processing speed predicted GCS in older but not younger adults. Future research may be needed to verify the training effect of processing speed on GCS. This study also further examined cognitive factors related to processing speed in aging and the relationships between cognitive processing speed and verbal fluency, cognitive inhibition, and divided attention. A stepwise regression analysis indicated that only verbal fluency contributed significantly to cognitive processing speed in older adults, accounting for 21% of the variance. These observations suggest that age-related changes of prefrontal regions may not fully explain age-related decline in cognitive processing speed.