Three patients with childhood onset symptomatic dystonia responded to levodopa. None fulfilled criteria for a diagnosis of "dopa responsive dystonia" (Segawa9s disease). One may have had athetoid cerebral palsy for almost 25 years. All obtained dramatic and sustained benefit from levodopa therapy. A therapeutic trial of levodopa is advised in all patients in whom dystonia has developed in childhood or early adult life, regardless of suspected aetiology or duration of symptoms.
Abstract We investigated the therapeutic effects of milacemide in seven patients with myoclonus and three patients with the stiff‐person syndrome in an open‐label trial. Milacemide was initiated at 800 mg/day and was gradually increased to a maximum dosage of 2,400 mg/day. No significant improvement occurred in the 10 patients.
Abstract Voluntary movements, such as the self‐paced finger extension task used in the present experiments, are preceded by a slowly rising negative electroencephalographic potential [the movement‐related cortical potential (MRCP)]. The early NS1 component of the potential was no different in patients with primary dystonia affecting the arm (n = 6) compared with matched controls. In contrast, the peak amplitude of the MRCP was smaller in the patients, despite the fact that the movements made by the two groups were very similar; it was of equal size over both left and right hemispheres, rather than being larger on the side contralateral to the movement. These results are similar to those observed by others in patients with symptomatic dystonia secondary to lesions of the basal ganglia or their output pathways and may reflect abnormal basal ganglia input to motor areas of cortex before the onset of a self‐paced movement.
This article reviews the neurophysiological abnormalities described in Huntington's disease. Among the typical features of choreic movements are variable and random patterns of electromyographic (EMG) activity, including cocontraction of agonist and antagonist muscles. Studies of premotor potentials show that choreic movements are not preceded by a Bereitschaftspotential, therefore demonstrating that choreic movement is involuntary. Early cortical median-nerve somatosensory-evoked potentials have reduced amplitudes and the reduction correlates with reduced glucose consumption in the caudate nucleus. Long-latency stretch reflexes evoked in the small hand muscles are depressed. These findings may reflect failed thalamocortical relay of sensory information. In Huntington's disease, the R2 response of the blink reflex has prolonged latencies, diminished amplitudes, and greater habituation than normal. These abnormalities correlate with the severity of chorea in the face. Patients with Huntington's disease perform simple voluntary movements more slowly than normal subjects and with an abnormal triphasic EMG pattern. Bradykinesia is also present during their performance of simultaneous and sequential movements. Eye movements show abnormalities similar to those seen in arm movements. In Huntington's disease, arm movement execution is associated with reduced PET activation of cortical frontal areas. Studies using transcranial magnetic stimulation show that patients with Huntington's disease have normal corticospinal conduction but some patients have a prolonged cortical silent period. Bradykinesia results from degeneration of the basal ganglia output to the supplementary motor areas concerned with the initiation and maintenance of sequential movements. The coexisting hyperkinetic and hypokinetic movement disorders in patients with Huntington's disease probably reflect the involvement of direct and indirect pathways in the basal ganglia–thalamus–cortical motor circuit.
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