Reliability and factor structure of the Short Problem Behaviors Assessment for Huntington's disease (PBA-s) in the TRACK-HD and REGISTRY studies.

The authors report the inter-rater reliability and factor structure of the Short Problem Behaviors Assessment (PBA-s), a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. Video recordings of 410 PBA-s interviews were rescored by an independent rater, and Cohen's kappa calculated to assess inter-rater reliability. The mean kappa was 0.74 for severity and 0.76 for frequency scores, whereas weighted kappa (allowing scores to differ by 1 point) was 0.94 for severity and 0.92 for frequency scores. The results of factor analysis were consistent with previous studies using other measures. The authors conclude that the PBA-s is a reliable measure.

Quantitative assessment of attribution of intentions to others in schizophrenia using an ecological video-based task: a comparison with manic and depressed patients.

Schizophrenia is characterized by the impairment of several facets of social cognition. This has been demonstrated in numerous studies that focused on specific aspects of social cognition such as the attribution of intentions, emotions, or false beliefs to others. However, most of these studies relied on complex verbal descriptions or impoverished social stimuli. In the present study, we evaluated a new task (Versailles-Situational Intention Reading, V-SIR) that is based on video excerpts depicting complex real-life scenes of social interactions. Subjects were required to rate the probabilities of several affirmations of the intentions of one of the characters. The V-SIR task was administered to schizophrenic patients (N=15), depressed patients (N=12), manic patients (N=15), and healthy controls (N=15). The performance of schizophrenic patients was significantly impaired in comparison to healthy and depressed subjects. There was a trend toward a significant difference between schizophrenic and manic patients. Manic patients also demonstrated impaired performance relative to healthy subjects. Schizophrenic patients' V-SIR scores were significantly correlated with their scores on another attribution of intentions task that used comic strips. These results show that tasks based on more ecological stimuli are powerful enough to detect theory-of-mind abnormalities in pathological populations such as schizophrenic patients.

Clinical relevance of electrophysiological tests in the assessment of patients with Huntington's disease.

Assessment programs recently designed to follow-up patients with Huntington's disease (HD) in therapeutic trials have not included electrophysiological testing in the list of mandatory examinations. This omission is likely due to the current lack of data establishing a clear correlation between the electrophysiological results and those of clinical assessment. We address this issue in a cohort of 36 patients at relatively early stages of the disease (I and II). Electrophysiological studies comprised the recording of palmar sympathetic skin responses (SSRs), blink reflexes (BRs), thenar long latency reflexes (LLRs), cortical somatosensory evoked potentials (SEPs), and electromyographic silent periods evoked by transcranial magnetic stimulation (SPs). Results were analyzed with reference to disease duration and staging and to specific cognitive, psychiatric, and motor alteration. SEPs were the most and very sensitive markers, because they were abnormal in 94% of patients. Except for LLRs, alteration of electrophysiological results increased in parallel to the evolution of the disease. Except for LLRs and SSR latency, electrophysiological results correlated with those of specific clinical examinations. In particular, an increased BR latency or a reduced amplitude of the N20 component of SEPs correlated with the extent of bradykinesia, whereas a reduced amplitude of SSRs or of the N30 component of SEPs correlated with hyperkinesia. Overall, electrophysiological tests, in particular SEPs and BRs, appeared sensitive and interesting in the follow-up of HD patients and correlated with various clinical parameters, suggesting that these easy to perform and noninvasive repeatable examinations could be added fruitfully to the assessment programs for HD.