Psychosis in Neurodegenerative Dementias: A Systematic Comparative Review.

Background: Psychosis, characterized by delusions and/or hallucinations, is frequently observed during the progression of Alzheimer's disease (AD) and other neurodegenerative dementias (ND) (i.e., dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD)) and cause diagnostic and management difficulties. Objective: This review aims at presenting a concise and up-to-date overview of psychotic symptoms that occur in patients with ND with a comparative approach. Methods: A systematic review was conducted following the PRISMA guidelines. 98 original studies investigating psychosis phenotypes in neurodegenerative dementias were identified (40 cohort studies, 57 case reports). Results: Psychosis is a frequently observed phenomenon during the course of ND, with reported prevalence ranging from 22.5% to 54.1% in AD, 55.9% to 73.9% in DLB, and 18% to 42% in FTD. Throughout all stages of these diseases, noticeable patterns emerge depending on their underlying causes. Misidentification delusions (16.6-78.3%) and visual hallucinations (50-69.6%) are frequently observed in DLB, while paranoid ideas and somatic preoccupations seem to be particularly common in AD and FTD, (respectively 9.1-60.3% and 3.10-41.5%). Limited data were found regarding psychosis in the early stages of these disorders. Conclusions: Literature data suggest that different ND are associated with noticeable variations in psychotic phenotypes, reflecting disease-specific tendencies. Further studies focusing on the early stages of these disorders are necessary to enhance our understanding of early psychotic manifestations associated with ND and help in differential diagnosis issues.

Personality and Neuropsychological Profiles in Friedreich Ataxia.

Friedreich ataxia, an autosomal recessive mitochondrial disease, is the most frequent inherited ataxia. Many studies have attempted to identify cognitive and affective changes associated with the disease, but conflicting results have been obtained, depending on the tests used and because many of the samples studied were very small. We investigated personality and neuropsychological characteristics in a cohort of 47 patients with genetically confirmed disease. The neuropsychological battery assessed multiple cognition domains: processing speed, attention, working memory, executive functions, verbal memory, vocabulary, visual reasoning, emotional recognition, and social cognition. Personality was assessed with the Temperament and Character Inventory, and depressive symptoms were assessed with the Beck Depression Inventory. We found deficits of sustained attention, processing speed, semantic capacities, and verbal fluency only partly attributable to motor deficit or depressed mood. Visual reasoning, memory, and learning were preserved. Emotional processes and social cognition were unimpaired. We also detected a change in automatic processes, such as reading. Personality traits were characterized by high persistence and low self-transcendence. The mild cognitive impairment observed may be a developmental rather than degenerative problem, due to early cerebellum dysfunction, with the impairment of cognitive and emotional processing. Disease manifestations at crucial times for personality development may also have an important impact on personality traits.

Deep brain stimulation of the internal pallidum in Huntington's disease patients: clinical outcome and neuronal firing patterns.

Deep brain stimulation (DBS) of the internal globus pallidus (GPi) could treat chorea in Huntington's disease patients. The objectives of this study were to evaluate the efficacy of GPi-DBS to reduce abnormal movements of three patients with Huntington's disease and assess tolerability. Three non-demented patients with severe pharmacoresistant chorea underwent bilateral GPi-DBS and were followed for 30, 24, and 12 months, respectively. Primary outcome measure was the change of the chorea and total motor scores of the Unified Huntington's Disease Rating Scale between pre- and last postoperative assessments. Secondary outcome measures were motor changes between ventral versus dorsal and between on- and off- GPi-DBS. GPi neuronal activities were analyzed and compared to those obtained in patients with Parkinson's disease. No adverse effects occurred. Chorea decreased in all patients (13, 67 and 29%) postoperatively. Total motor score decreased in patient 2 (19.6%) and moderately increased in patients 1 and 3 (17.5 and 1.7%), due to increased bradykinesia and dysarthria. Ventral was superior to dorsal GPi-DBS to control chorea. Total motor score increased dramatically off-stimulation compared to ventral GPi-DBS (70, 63 and 19%). Cognitive and psychic functions were overall unchanged. Lower mean rate and less frequent bursting activity were found in Huntington's disease compared to Parkinson's disease patients. Ventral GPi-DBS sustainably reduced chorea, but worsened bradykinesia and dysarthria. Based on these results and previous published reports, we propose to select non-demented HD patients with severe chorea, and a short disease evolution as the best candidates for GPi-DBS.