Focal reflex myoclonus.
In a patient with reflex myoclonus limited to the right side of the body, stimulation of the right median nerve in the index finger or wrist elicited a very large somatosensory evoked response (SER) and a long loop C reflex which represents an electrically evoked myoclonic response. It is suggested that the pathway for the C reflex is through peripheral nerve, dorsal funiculus of spinal cord, contralateral VP nucleus of thalamus, sensorimotor cortex, corticospinal tract, and anterior horn cell. The large SER, C reflex, and myoclonic jerks are presumed to result from a release effect causing increased excitability at central synapses along this pathway. The patient presented has a large atrophic vascular lesion involving the left frontotemporoparietal region and involvement of pathways through the right superior cerebellar peduncle to account for the neural dysfunction.
D000368:Aged; D002561:Cerebrovascular Disorders / Q000150:complications / Q000503:physiopathology*; D003975:Diazepam / Q000627:therapeutic use; D004558:Electric Stimulation; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008475:Median Nerve / Q000503:physiopathology; D009119:Muscle Contraction; D009132:Muscles / Q000503:physiopathology; D009207:Myoclonus / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D012018:Reflex; D012631:Secobarbital / Q000627:therapeutic use; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013116:Spinal Cord / Q000503:physiopathology; D013787:Thalamic Nuclei / Q000503:physiopathology
D012631:Secobarbital; D003975:Diazepam