[Exploration of traumatic brain-injury attention difficulty by event-related potentials]. / Exploration des troubles attentionnels des traumatisés crâniens avec les potentiels évoqués cognitifs.

OBJECTIVE: To specify, in cognitive processing leading to an action, the localization of difficulties in attention following severe, traumatic brain injury. METHOD: Stimulus-locked and response-locked event-related potentials were recorded during a Stroop task in 25 patients with traumatic brain injury and 25 control subjects approximately 4 months after the accident. The latency and amplitude of the waves were compared between the two groups and correlated with clinical data. RESULTS: The reaction times of brain-injured patients were significantly longer than those of the control group, but neither the number of errors nor the interference differed between the groups. Electrophysiological recordings showed early abnormalities between 100 and 200 ms after stimulus onset. The key area could be the medial occipitotemporal side connected with frontal regions. Recordings also showed disruptions in motor program monitoring, which implied frontomedial areas. CONCLUSION: This protocol allows for precisely dating cognitive abnormalities. Future studies should relate cognitive with neuropsychological abnormalities and examine the possibilities of later regression.

[Auditive and somato-sensory event-related potentials in comas: prognostic value for awakening, social and professional reinstatement]. / Les potentiels évoqués cognitifs, auditifs et somesthésiques dans les comas: valeur pronostique pour l'éveil et la réintégration socioprofessionnelle.

OBJECTIVE: To appreciate prognostical value of event-related potentials in comatose states and the influence of the stimulation's modality. PATIENTS AND METHODS: Thirty-five patients were recorded with the auditory modality whose thirteen were also recorded with the somesthetic modality. They were free of sedation except for five. For 21 patients out of coma, it was possible to get information about their social readaptation 14 months later. RESULTS: When present, cognitive components predict awakening in 100 % of the cases, but only 50 % of the patients who awake had these components. The somesthetic modality seemed to enlarge their detection, but did not improve short-term forecasts. We could not confirm their absence could hamper social reinstatement. CONCLUSION: Event-related potentials are strengthened as having excellent positive prognostic value. Further studies should clarify the interest of the somesthetic modality, and the possibility to get remote prognostic.

[Can neurophysiologic tests differentiate between depression and dementia?]. / Les examens neuro-physiologiques peuvent-ils différencier dépression et démence?

In order to evaluate the clinical utility of neuro-physiological tests in distinguishing between depression and dementia, we compared quantified EEG and event-related potentials (ERP) in 13 depressed and 12 demented patients. Their cognitive functions were clinically assessed by the ERFC test. When scored with a discriminant function, EEG misclassified one patient and all were well classified with ERP. Nevertheless this exam could be clearly obtained in only 7 demented and 5 depressed patients. Although a therapeutic effect could not be absolutely discarded, these results show that these tests, when practicable, can be helpful when clinical diagnosis is uncertain.