Cognitive and Behavioral Neurology最新文献

Background: Whether the effect of switch probability on switch and mixing costs is explained by an activation or preparation account is unclear.

Objective: To investigate the account of the effect of switch probability on switch and mixing costs.

Method: We used a cued task-switching paradigm with three switch probabilities (high, 75%; medium, 50%; and low, 25%) with 19 healthy young adults and recorded the cue- and target-locked event-related potentials (ERPs) and behavioral performance. The task included switch and stay trials under high, medium, and low switch conditions, as well as pure trials.

Results: There was no significant difference in reaction time (RT) in switch and mixing costs between the high and medium switch conditions. The RT in switch and mixing costs in the high and medium switch conditions was significantly less and more than in the low switch condition, respectively. The cue-locked ERPs revealed significant effects on mixing costs (stay - pure) that were cue early frontal positivity (260-300 ms) in the high and medium switch conditions, and on switch costs (switch - stay) that were cue early central positivity (240-260 ms) in the low switch condition. Moreover, the target-locked ERPs of the mixing costs revealed significant effects on mixing costs that were target P3b (440-540 ms) in all three switch conditions, and on switch costs that were target P3b in the medium and low switch conditions.

Conclusion: The effect of switch probability on switch and mixing costs is explained by the activation account.

Background: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic small-vessel disease that is characterized by a wide range of neurologic and neuropsychological impairments. Constructional impairments have been reported in some cases but have never been assessed systematically.

Objective: To evaluate constructional abilities and their cognitive and neural correlates in nondemented individuals with CADASIL.

Method: Thirty individuals with CADASIL who were not affected by clinically relevant cognitive deterioration and 30 healthy controls (HC) underwent an extensive cognitive assessment and paper-and-pencil visuoconstructional tasks in order to detect constructional impairments. Performance on the visuoconstructional tasks was correlated with the cognitive assessment scores and with quantitative indices of regional gray matter atrophy (obtained via FreeSurfer image analysis) and white matter involvement.

Results: The individuals with CADASIL achieved significantly lower scores on the cognitive assessment compared with the HC. Poor visuoconstructional abilities were observed in seven (23.3%) of the individuals with CADASIL when performing the copy drawing task and in nine (30%) when performing the Rey Complex Figure Test. Logistic regression revealed that visuoconstructional impairments were significantly associated with scores on the Frontal Assessment Battery and the Attentional Matrices Test. Morphometric results revealed that scores on the visuoconstructional tasks were related to gray matter atrophy of the left frontal lobe and right parietal lobe.

Conclusion: Impairments on visuoconstructional tasks are quite common in individuals with CADASIL, even in the lack of clinically relevant cognitive deterioration, and are critically related to frontal and parietal atrophy.

Background: Semantic category fluency is a widely used task involving language, memory, and executive function. Previous studies of bilingual semantic fluency have shown only small differences between languages. Graph theory analyzes complex relationships in networks, including node and edge number, clustering coefficient, average path length, average number of direct neighbors, and scale-free and small-world properties.

Objective: To shed light on whether the underlying neural processes involved in semantic category fluency testing yield substantially different networks in different languages.

Method: We compared languages and methods using both network analysis and conventional analysis of word production. We administered the animal naming task to 51 Russian-English bilinguals in each language. We constructed network graphs using three methods: (a) simple association of unique co-occurring neighbors, (b) corrected associations between consecutive words occurring beyond chance, and (c) a network community approach using planar maximally filtered graphs. We compared the resultant network analytics as well as their scale-free and small-world properties.

Results: Participants produced more words in Russian than in English. Small-worldness metrics were variable between Russian and English but were consistent across the three graph theory analytical methods.

Conclusion: The networks had similar graph theory properties in both languages. The optimal methodology for creating networks from semantic category fluency remains to be determined.

Background: Individuals with probable Alzheimer disease (AD) may perform below cutoffs on traditional, memory-based performance validity tests. Previous studies have found success using event-related potentials (ERPs) to detect feigned neurocognitive impairment in younger populations.

Objective: To evaluate the utility of an auditory oddball task in conjunction with the P3b peak amplitude to distinguish probable AD from simulated dementia.

Method: Twenty individuals with probable AD and 20 older healthy controls (HC) underwent an ERP auditory oddball protocol and the Test of Memory Malingering (TOMM). The HC were asked to perform honestly for one condition and to simulate dementia for the other. The individuals with probable AD were asked to perform honestly. The P3b peak amplitude and button press accuracy were collected from each participant and were analyzed to determine their effectiveness in detecting performance validity.

Results: The P3b peak amplitude remained stable regardless of behavioral condition in the HC group. When combined with the TOMM Trial 2 score, the P3b peak amplitude further improved the ability to correctly differentiate individuals with probable AD from HC simulating dementia with 100% sensitivity and 90% specificity.

Conclusion: The P3b peak amplitude was found to be an effective physiologic measure of cognitive impairment in individuals with probable AD compared with HC simulating dementia. When combined with the TOMM Trial 2 score, the P3b peak amplitude served as a promising performance validity measure for differentiating individuals with probable AD from HC simulating dementia.

Background: Abbreviated neurocognitive tests offer a practical alternative to full-length versions but often lack clear interpretive guidelines, thereby limiting their clinical utility.

Objective: To replicate validity cutoffs for the Boston Naming Test-Short Form (BNT-15) and to introduce a clinical classification system for the BNT-15 as a measure of object-naming skills.

Method: We collected data from 43 university students and 46 clinical patients. Classification accuracy was computed against psychometrically defined criterion groups. Clinical classification ranges were developed using a z -score transformation.

Results: Previously suggested validity cutoffs (≤11 and ≤12) produced comparable classification accuracy among the university students. However, a more conservative cutoff (≤10) was needed with the clinical patients to contain the false-positive rate (0.20-0.38 sensitivity at 0.92-0.96 specificity). As a measure of cognitive ability, a perfect BNT-15 score suggests above average performance; ≤11 suggests clinically significant deficits. Demographically adjusted prorated BNT-15 T-scores correlated strongly (0.86) with the newly developed z -scores.

Conclusion: Given its brevity (<5 minutes), ease of administration and scoring, the BNT-15 can function as a useful and cost-effective screening measure for both object-naming/English proficiency and performance validity. The proposed clinical classification ranges provide useful guidelines for practitioners.