Journal of neurology, neurosurgery, and psychiatry
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J. Neurol. Neurosurg. Psychiatr. · Jan 1990
EMG responses in leg muscles to postural perturbations in Huntington's disease.
This paper compares leg muscle electromyogram (EMG) responses to sudden toe-up tilts of a moveable platform in patients with Huntington's disease (HD), clinically normal offspring at risk of developing HD (HD risks) and healthy controls. The EMG pattern in standing subjects and patients consisted of short- and middle-latency responses (SL and ML) in the stretched triceps surae muscles and long-latency responses (LL) in the shortened tibialis anterior muscles. The SL response could be further divided into two distinct subcomponents termed SL1 and SL2. ⋯ In the sitting condition, the EMG responses of the HD patients and of the HD risks did not differ from those of controls: in all groups SL1 was reduced and delayed, SL2 slightly enhanced, while ML and LL were absent. Because both afferent and efferent conduction times are normal in HD, the delayed LL onset reflects abnormal supraspinal organisation of postural control in HD, and indicates that basal ganglia may have a modulatory effect on the LL responses. The normal EMG responses in the sitting patients suggest appropriate regulation of these responses according to postural set in HD.
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J. Neurol. Neurosurg. Psychiatr. · Jan 1990
Pain-related somatosensory evoked potentials in cortical reflex myoclonus.
To elucidate the sensitivity to pain stimuli in patients with cortical reflex myoclonus, pain-related somatosensory evoked potentials (pain SEPs) following CO2 laser stimulation and conventional electrically-stimulated SEPs (electric SEPs) were compared in four patients with cortical reflex myoclonus. The P25 peak of electric SEPs was considerably enhanced but the P320 potential of pain SEPs was of normal amplitude in all patients. ⋯ In our previous study of the scalp distribution in normal subjects, a subcortical site, probably the thalamus, was considered to be the generator source of P320. Because most pain stimuli do not reach the cortex, patients with cortical reflex myoclonus are not sensitive to pain stimuli and P320 in pain SEPs is not enhanced.
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J. Neurol. Neurosurg. Psychiatr. · Jan 1990
Case ReportsCongenital Horner's syndrome with unilateral facial flushing.
Two patients with congenital Horner's syndrome had unilateral facial flushing. Both showed pupillary supersensitivity to epinephrine as well as anhidrosis on the affected side of the face and neck. ⋯ Thermal vasodilation in the major portions of the face is regulated by sympathetic vasodilator fibres, and less predominantly by adrenergic vasoconstrictor fibres. The asymmetry of facial flushing may have been caused by impaired sympathetic vasodilation and further intensified by active vasoconstriction due to supersensitivity to circulating catecholamine on the affected side.