Biomedical subjects
G D Wright
Publications and source records attributed to G D Wright.
Retinal arteriolar occlusion in multiple sclerosis.
A 25-year-old white man presented with acute multiple sclerosis manifested by right blindness, difficulty urinating, and paresthesias and weakness of both legs. Retinal examination revealed a distal occlusion of the descending branch of the superior temporal arteriole leading to an area of retinal ischemia of the right eye. The optic disc was edematous, and there were focal areas of periphlebitis. All retinal signs resolved in three weeks, and the only abnormality that persisted was a pale right optic disc. The finding of small arteriolar disease is unusual and may represent another possible pathogenetic mechanism in multiple sclerosis.
A double-blind trial of chronic cerebellar stimulation in twelve patients with severe epilepsy.
Twelve patients with severe intractable epilepsy were treated by chronic cerebellar stimulation under double-blind conditions for six months. No reduction in seizure frequency occurred that could be attributed to stimulation, though eleven of the patients considered that the trial had helped them. One patient experienced fewer episodes of incontinence during stimulation. Cerebellar stimulation in its present form cannot be recommended for the treatment of severe intractable epilepsy.
Biopsy and post-mortem findings in a patient receiving cerebellar stimulation for epilepsy.
Cerebellar stimulating equipment was implanted in a 24-year-old male with severe epilepsy. He received continuous alternating stimulation for at least two months, intermittent bilateral stimulation on demand for at least two months and numerous short bursts of stimulation during preliminary testing and calibration of the apparatus. The patient died during a prolonged grand mal seizure 16 months after implantation and this paper reports the findings at necropsy. A special study was made of the degree of tissue damage in the cerebellar hemispheres resulting from implantation of the electrodes and subsequent cerebellar stimulation. There was deep grooving of the upper aspect of the cerebellum under the electrodes but only a minor degree of neuronal loss and gliosis was observed in the underlying cortex. Purkinje cell populations in the cerebellum at necropsy were similar to those in a biopsy specimen taken 16 months previously during implantation. The electrodes were covered with a thick layer of fibrous tissue but they were not adherent to the cerebellar surface. Thus, the main significant findings in the present case were the very slight structural damage to the cerebellum in contact with the electrodes and the intense fibrosis around the electrodes themselves. These features are discussed in relation to the efficacy of long-term cerebellar stimulation.
Absence of clinical or physiological changes during short-term cerebellar stimulation in a patient with Lafora body disease.
A 17-year-old girl with Lafora body disease received short-term stimulation but her epilepsy failed to improve and no changes were detected in her EEG. Neither visual nor somatosensory evoked potentials were changed by short bursts of cerebellar stimulation.
Calibration of clinical cerebellar and deep brain stimulation systems.
The increasing use of electrical stimulation of the brain for relief of pain, spasticity and epilepsy has introduced unfamiliar techniques into clinical neurological and neurosurgical practice. In view of the evidence that excessive levels of stimulation can damage brain tissue, it is of great importance to monitor the dose of stimulation. A review of recent clinical papers suggests that many centres do not measure the dose accurately, relying on arbitrary dial settings on external transmitters. This paper reviews that factors that affect the dose received by the patient and suggests methods of measuring them, at operation and subsequently, which should routinely be employed by clinicians implanting stimulators.
An isolated right hypoglossal nerve palsy in association with infectious mononucleosis.
Following an upper respiratory tract infection, a teenage girl developed an isolated right XII nerve palsy; subsequently she was shown to have infectious mononucleosis. After 24 weeks her tongue had virtually recovered.
The ultrastructure of the pineal ganglion in the ferret.
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Epilepsy, the cerebellum, and cerebellar stimulation.
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