Rev Neurol France
-
Event-related potentials are electric brain manifestations evoked by mental activities. This neurophysiological technique is able to describe temporal succession of cognitive processing and allows to measure the neurobiological correlates of each cognitive activity. The evoked potentials of the oddball paradigm and the Contingent Negative Variation (CNV) are also concerned by clinical applications in neuropsychiatry, in neurology and in psychopharmacology. ⋯ Those hypothesis reveal that a shift in the brain metabolic homeostasis could be the common factor of migraine attacks. The clinical contribution of event-related potentials is of little use in the diagnosis of migraine. But two purposes have been suggested: the differential diagnosis between common migraine and tension-type headaches and the monitoring of beta-blocking agents prophylaxis.
-
We report a case of a mitochondrial cytopathy (MERRF) with a late diagnosis because of the absence of Ragged-Red Fibers (RRF) in the first muscular biopsy performed in childhood. Eight years after the onset of the disease the familial history and the clinical manifestations were very suggestive of a mitochondrial cytopathy and a second biopsy was performed confirming the diagnosis of MERRF. The authors discuss several hypotheses to explain the negativity of the first muscular biopsy. The absence of ragged-red fibers does not exclude the diagnosis of a mitochondrial cytopathy and other investigations are justified such as the biochemical study of the respiratory chain and the molecular analysis of mitochondrial DNA.