Electroencephalography and clinical neurophysiology
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Electroencephalogr Clin Neurophysiol · Nov 1998
Auditory and somatosensory evoked potentials in coma following spontaneous cerebral hemorrhage: early prognosis and outcome.
The aim of this study was to check the prognostic power of auditory brain-stem responses (ABRs) and somatosensory evoked potentials (SEPs) in coma following spontaneous cerebral hemorrhage. Seventy patients comatose following subarachnoidal or hypertensive hemorrhage were submitted to ABR and SEP recordings during the acute phase of clinical course. Twenty-one patients survived (30%), two remained vegetative (2.9%) and 47 died (68.1%). ⋯ ABRs and SEPs showed a much closer correlation with outcome (P < 0.001): their combined use allowed there to be a sensitivity of 96%, a specificity of 90% and a predictive power of 96%; the relative risk of poor outcome in patients with at least one abnormal modality was equal to 223 times the one for patients with normal evoked potentials. Moreover, in surviving patients a significant relationship appeared to exist between abnormalities of SEPs during the acute phase and the severity of disability. Our results confirm the prognostic effectiveness of short latency evoked potentials in cerebral hemorrhage: they are far superior to clinical data, being able to yield a marked decrease of falsely optimistic predictions.
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Neurophysiological techniques for the evaluation of pain in humans have made important advances in the last decade. A number of features of neuroanatomy and physiology of nociception qualifies pain as a multidimensional phenomenon which is rather unique among the sensory systems and which poses a number of technical and procedural requirements for its appropriate diagnostic assessment. ⋯ Particular emphasis is put upon laser-evoked potentials and their application for diagnosis, pathophysiological description and monitoring of patients with neurological disorders and abnormal pain states. Future perspectives in this growing field of research are discussed briefly.
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Electroencephalogr Clin Neurophysiol · Sep 1998
Randomized Controlled Trial Clinical TrialRelation of olfactory event-related potentials to changes in stimulus concentration.
The aim of this study was to investigate the influence of odorant concentration on the olfactory event-related potential (OERP). ⋯ The results indicated that both OERP amplitudes and latencies are related to the concentration of olfactory stimuli. They also suggested that latencies exhibit a stronger relation to changes in stimulus intensity compared to OERP amplitudes.
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Electroencephalogr Clin Neurophysiol · Sep 1998
Exteroceptive suppression of temporalis muscle activity in patients with fibromyalgia, tension-type headache, and normal controls.
Changes of the second suppressive period (ES2) of the exteroceptive suppression of the temporalis muscle activity are found in patients with chronic tension-type headache (TTH) and are suggested to reflect an abnormal endogenous pain control system. We investigated whether similar changes are found in patients with the fibromyalgia syndrome (FMS) that is also believed to result from disturbed central pain processing. ⋯ The duration of ES2 (+/-SD) in FMS patients was 30.6+/-7.5 ms and was not significantly different from the control group (33.1+/-7.8 ms), whereas it was significantly shortened in TTH patients (22.9+/-11.5 ms). Our results indicate that, despite similar concepts on the pathophysiology of the two chronic pain disorders, there are no comparable changes of this brain stem reflex activity in FMS.