Abstract-Verbal fluency refers to the ability to generate as many words as possible in a limited time interval, without repetition and according to either a phonologic (each word begins with a given letter) or a semantic rule (each word belongs to a given semantic category). While current literature suggests the involvement of left fronto-temporal structures in fluency tasks, whether the same or distinct brain areas are necessary for each type of fluency remains unclear. We tested the hypothesis for an involvement of partly segregated cortico-subcortical structures between phonologic and semantic fluency by examining with a voxel-based lesion symptom mapping approach the effects of brain lesions on fluency scores corrected for age and education level in a group of 191 unselected braindamaged patients with a first left or right hemispheric lesion. There was a positive correlation between the scores to the two types of fluency, suggesting that common mechanisms underlie the word generation independent of the production rule. The lesion-symptom mapping revealed that lesions to left basal ganglia impaired both types of fluency and that left superior temporal, supramarginal and rolandic operculum lesions selectively impaired phonologic fluency and left middle temporal lesions impaired semantic fluency. Our results corroborate current neurocognitive models of word retrieval and production, and refine the role of cortical-subcortical interaction in lexical search by highlighting the common executive role of basal ganglia in both types of verbal fluency and the preferential involvement of the ventral and dorsal language pathway in semantic and phonologic fluency, respectively. Ó
Background. A successful interplay between prefrontal and domain-specific language areas is critical for language processing. Previous studies involving people with aphasia have shown that executive control processes might act on lexical-semantic representations during retrieval. Modulating the prefrontal control network by means of noninvasive brain stimulation might, therefore, improve lexical access in people with aphasia. Objective. The present study investigates the effects of prefrontal transcranial direct current stimulation (tDCS) on lexical access in chronic poststroke aphasia. Methods. We report data of 14 participants with chronic poststroke aphasia. We used a sham-tDCS (S-tDCS) controlled and double-blind within-subjects design. Performances in picture naming, verbal fluency, and word repetition were assessed immediately after stimulation. Results. As compared with S-tDCS, anodal tDCS (A-tDCS) improved verbal fluency as well as the speed of naming high frequency words, but not word repetition. Conclusion. The results of our study suggest that the brain network dedicated to lexical retrieval processing can be facilitated by A-tDCS over the left dorsolateral prefrontal cortex. This finding supports the notion that strengthening executive control functions after stroke could complement speech and language-focused therapy.
The objective of this case study was to describe the neuropsychological rehabilitation of a 16-year-old patient who presented a Cerebellar Cognitive Affective Syndrome (CCAS) following a bilateral cerebellar hemorrhage. The patient presented severe and diffuse cognitive deficits, massive behavioral disorders, and emotion regulation difficulties. The cognitive rehabilitation was performed in the chronic phase (one year after the onset of the hemorrhage) using a transdisciplinary neurobehavioral approach based on the patient's favorite interest (soccer). A significant behavioral and cognitive improvement was observed. The patient became progressively independent in all activities of daily living and was discharged home. The Functional Independence Measure at discharge was 124=126 (vs. 37=126 at entry). The patient was able to complete his schooling despite the mild cognitive and behavioral sequelae. This first description of the use of neurobehavioral therapy in a case of chronic CCAS suggests that (a) major clinical improvement can occur more than one year after the onset of the CCAS, showing the importance of long-term and intensive neurorehabilitation; and (b) when the cerebellum cannot properly play its regulator role in cognition, neuropsychological intervention through a behavioral and cognitive approach can be of great help by acting as an external modulator to help the patient regain control over himself.
Neuropsychological theories raise the question if in late bilinguals
Zusammenfassung. Die Frühdiagnostik subjektiv wahrgenommener oder fremdanamnestisch beobachteter kognitiver Beeinträchtigungen ist essenziell, um neurodegenerative Erkrankungen nachzuweisen oder behandelbare Ursachen wie internistische, neurologische oder psychiatrische Störungen auszuschliessen. Nur dadurch wird eine frühzeitige Behandlung ermöglicht. Im Rahmen des Projekts 3.1 der Nationalen Demenzstrategie 2014–2019 («Auf- und Ausbau regionaler und vernetzter Kompetenzzentren für die Diagnostik») hat sich der Verein Swiss Memory Clinics (SMC) zum Ziel gesetzt, Qualitätsstandards für die Demenzabklärung zu entwickeln und die wohnortsnahe Versorgung in diesem Bereich zu verbessern. In den vorliegenden Empfehlungen werden allgemeine Richtlinien der Diagnostik und einzelne Untersuchungsmöglichkeiten vorgestellt, sowie Standards für die diesbezüglichen Abläufe vorgeschlagen. Einzelne Bereiche wie Anamneseerhebung, klinische Untersuchung, Laborparameter, neuropsychologische Testung und neuroradiologische Verfahren werden als Teil der Standarddiagnostik ausführlich diskutiert, ergänzende Untersuchungsmethoden für differenzialdiagnostische Überlegungen abgebildet. Die wichtigsten Ziele der SMC-Empfehlungen zur Diagnostik der Demenzerkrankungen sind, möglichst allen Betroffenen Zugang zu einer qualitativ hochstehenden Diagnostik zu ermöglichen, die Frühdiagnostik der Demenz zu verbessern und den Grundversorgern sowie den Mitarbeitenden der Memory Clinics ein nützliches Instrument für die Abklärung anzubieten.
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