Eight anticonvulsant drugs – including clonazepam, diazepam and phenobarbital – were tested for their effects on GABA-stimulated chloride uptake in rat cerebral cortical microsacs (unfiltered synaptoneurosomes). “Mid” and “high” therapeutic concentrations were screened, and, if significant enhancement was found, full concentration-response tests were done. In the initial screens, enhancement of GABA-stimulated uptake was found only with phenobarbital, clonazepam and diazepam. In subsequent concentration-response tests, the effects of phenobarbital were found to occur throughout the range of normal, anticonvulsant concentrations, whereas the effects of clonazepam and diazepam were observed only above the concentrations normally used for the chronic control of seizures or anxiety. These data suggest that phenobarbital's anticonvulsant effects are mediated via the GABAA receptor complex, but that the low-dose effects of the benzodiazepines may be mediated via some other mechanism.

Although fatigue is recognized as a symptom of MS, there have been insufficient methods for evaluating this symptom. We administered the Fatigue Impact Scale to 85 MS patients and 20 hypertensive patients. Neurologic impairment, mental health, and general health status were also assessed. MS patients reported significantly higher fatigue impact than hypertensive patients. Most MS patients reported fatigue as either their worst (14%), or one of their worst (55%) symptoms. Disease classification and neurologic impairment had little bearing on Fatigue Impact Scale scores in the MS sample. The best predictive models for mental health and general health status in the MS sample both included the Fatigue Impact Scale as a significant factor. This study demonstrates that: 1) fatigue is a very prevalent and severe problem in MS, 2) fatigue impact cannot be predicted by clinical measures of neurologic impairment, 3) fatigue has a significant effect on the mental health and general health status of MS patients.

Sixteen stroke patients suffering from ataxic hemiparesis syndrome were studied with regional cerebral blood flow measured by 133-Xenon inhalation technique (12 patients) and by SPECT (HMPAO) (9 patients). The causative lesions (hematoma in 7 and infarct in 9), unilateral in 15 patients and bilateral in 1, were located in the posterior two-thirds of the corona radiata, thalamocapsular and subthalamus regions, or cerebral peduncle. Ataxia of the cerebellar type was unilateral in 15 patients and bilateral in 1 with similar, deep, bilateral causative lesions. Four patients presented some characteristics of proprioceptive ataxia (mixed ataxia). Associated cognitive disturbances were present in 9 patients and absent in 7. Eleven of the 12 subjects studied by 133-Xenon inhalation technique showed limited centro-parietal hypoperfusion, mainly in the inferior parietal lobule, ipsilateral to the causative lesion and bilaterally in the patient with bilateral lesions and ataxia. Ipsilateral hypoperfusion was confirmed in 7/9 patients studied by SPECT, which also demonstrated contralateral cerebellar hypoperfusion in 4 patients. These findings suggest that ataxic hemiparesis syndrome results from functional depression (diaschisis) consequent to the interruption at many levels of an “inferior parietal associative cortex - cerebellar anterior lobe” circuit.

We explored the effects of chronic lumbar intrathecal NMDA infusion (mini-osmotic pumps) in Sprague-Dawley rats on motor and sensory axon integrity. Several different infusion protocols, each given over a 4 week period were examined: 0.15 M NMDA in phosphate buffered saline; phosphate buffered saline without NMDA; and 0.20 M magnesium sulfate plus 0.15 M NMDA; 0.35 M NMDA. In two additional protocols, 0.15 M NMDA or phosphate buffered saline were infused for a total of 8 weeks. Within 1-2 weeks of the onset of NMDA, but not phosphate buffered saline infusions, the rats exhibited irritability, circling, biting and excessive grooming resulting in loss of hair, and skin ulcerations from autotomy localized to lumbar and sacral innervated dermatomes. Co-infusion of NMDA with magnesium sulfate almost completely prevented these findings. The behavioural changes were not associated with abnormalities of sensory or motor conduction. Intrathecal infusion of NMDA induces a chronic “central” experimental pain disorder in rats, localized to the cord segment with the greatest exposure to the infusion, without involvement of peripheral sensory axons and sparing the axonal integrity of anterior horn cells.

Two siblings, a 35-year-old male and a 37-year-old female, offspring of first cousins, presented with a hereditary motor and sensory neuropathy with type I clinical features which began to manifest at about age 10 years. Nerve biopsy in the proband showed it to be a type characterized by excessive myelin outfolding. Morphometric study revealed hypomyelination with focal thickenings due to outfoldings. Clinical, electrophysiological and morphological findings are virtually identical to those described by Ohnishi et al. The peculiarity of the neuropathological picture suggests a particular form of hereditary motor and senory neuropathy.

We compare complications from 66 sural nerve biopsies in 41 patients with diabetic peripheral neuropathy to 40 patients with neuropathy from other causes, using a retrospective telephone survey. Diabetic patients were followed for a mean of 6.8 years and non-diabetics for 5.6 years. Mild long-term pain was described by 18.9% of patients overall with no difference between groups. Mild persistent sensory symptoms, insufficient to interfere with daily activity or warrant medical therapy, were reported by 63.6% of diabetic and 27.5% of non-diabetic patients (p < 0.006). Wound infection and severe pain were uncommon in both groups and no different in diabetics. Significant complications of sural nerve biopsy occurred no more frequently in diabetic than in non-diabetic patients. While sural nerve biopsy plays no role in the routine evaluation of diabetic peripheral neuropathy, it may be performed without increased risk when indicated in these patients to exclude other causes of neuropathy and in the context of research trials.

Acute femoral neuropathy after renal transplantation is an uncommon and rarely recognized complication. Recovery of the nerve is usual. Although rare, five cases have come to our attention in the past twenty years. A detailed clinical and electrophysiological analysis with a six month follow-up is presented. A review of sixteen other reported cases is also provided. The possible pathophysiology including direct compression and nerve ischemia, is discussed. We believe that nerve ischemia, possibly caused by a steal phenomenon, occurs in all cases following the anastomosis of the graft renal artery to the internal iliac artery, with a superimposed component of compression in some cases. The severity of ischemia probably determines the degree of recovery.

The complicated pathophysiological and immunological changes in the central nervous system of patients with neurocysticercosis produce a variety of signs and symptoms, which complicate the clinical and surgical management of this disease. A complete and objective classification is needed, to improve the medical approach as a whole. We studied 336 patients, in whom we classified neurocysticerosis according to criteria of viability and location of the parasite in the CNS: active form (37.2%) when the cysticercus is alive, transitional form (32.8%) when it is in the degenerative phase, and inactive form (30%) when the parasite is dead. This classification establishes the correlation between the different forms of neurocysticerosis and its clinical manifestations, and can be used for planning therapeutic strategies.

Gilles de la Tourette syndrome is a neurological disorder characterized by the presence of motor and vocal tics. Other associated features include complex motor and vocal tics, obsessive compulsive behavior and attention-deficit disorder. Although initially thought to be a rare condition, it now appears that the gene for Tourette syndrome may be present in as many as one in a thousand people, and is transmitted as an autosomal dominant trait. However, many individuals carrying the gene may exhibit only minimal symptoms. Neuropathophysiology of Tourette syndrome is unknown but investigations have suggested that the cause may be an abnormality either in the dopaminergic or endorphin receptor system within the basal ganglia. Treatment of Tourette syndrome involves education and counseling of the patient and family. Medications such as neuroleptics, serotonin-reuptake inhibitors, and stimulants are available to treat the manifestations of Tourette syndrome and need to be individualized for each patient.

To assess the frequency of subjective and objective dysphagia and its possible pulmonary sequelae, we prospectively studied 22 out-patients with Parkinson's disease; 15 spouses served as controls. All subjects answered a standard questionnaire concerning swallowing and respiratory functions and underwent barium swallow videofluoroscopy. Possible pulmonary infection was investigated by recordings of body temperature, ESR, leucocyte count, and chest X-ray. Patients had significantly more symptoms than controls, especially choking, piece-meal deglutition and regurgitation. Videofluoroscopy revealed tracheal aspiration in one patient, vestibular aspiration in one patient and in one control. Non-fluent swallowing movements were common in patients: abnormal bolus formation, delayed swallowing reflex, vallecular stasis, and piriform sinus residue. None of the subjects had signs of pulmonary infection. Both subjective and objective oro-pharyngeal dysfunction is frequent in ambulant Parkinson patients, but apparently does not produce demonstrable pulmonary infection.

The swallowing movements of 22 ambulant patients with Parkinson's disease were examined by videofluoroscopy, 15 spouses serving as controls. The relation between bolus volume and movement of the hyoid bone was studied in the lateral view to assess the adaptation of the pharynx musculature. Although movement characteristics of the hyoid varied considerably both intra- and interindividually, mean values followed typical patterns. In controls, the position of the hyoid before the start of the swallow tended to be lower as the bolus volume increased, apparently to create space in the oral cavity by lowering the floor of the mouth. This trend was not seen in the group of Parkinson patients. We suppose that this specific lack of adaptation represents hypokinesia. The amplitude of the hyoid movement did not change with increasing bolus volumes, either in patients or in controls. Moreover, Parkinson patients had many more aborted swallowing movements (“hesitations”) than controls, probably representing defective switching from the voluntary phase of swallowing to the involuntary, automatic phase.

A patient with a three year history of POEMS syndrome-polyneuropathy, hepatosplenomegaly M-protein, skin changes, optic disc edema, peripheral oedema, pleuritis, lymphadenopathy, and osteosclerotic myeloma is described. The patient had a twenty year history of psoriasis and impotence was the first sign of the disease. The pathophysiology of this multisystem disorder is unknown, although the M-protein is essential. No improvement was found after radiation, chemotherapy and steroid treatment.

The authors report, for the first time, the finding by magnetic resonance imaging of a neurofibroma at the craniocervical junction with upper cervical cord and lower brainstem compression causing complete apnea from birth. Subsequent subtotal resection of the neurofibroma resulted in the successful extubation of a previously ventilator-dependent patient. After a two month period of breathing spontaneously, the newborn developed an upper respiratory tract infection and was reintubated. The patient, unable to be weaned off of the respirator, was extubated and expired shortly thereafter, at the age of five months. The authors suggest that in newborns with unexplained apnea, MRI of the craniocervical junction is indicated. Certain patients may be discovered who have less compromised cervicomedullary function and are afflicted by less aggressive forms of neurofibromatosis type 1. These patients may benefit permanently from a surgical decompression.

A seventy-year-old woman suffered a fatal cerebellar rehemorrhage from a large venous aneurysm associated with a dural arteriovenous malformation (AVM) of the posterior fossa. The malformation, fed by branches of the right vertebral, occipital and middle meningeal arteries, had a nidus in the transverse sinus wall with a pedunculated extension reaching the pial surface of the adjacent cerebellum, from where the malformation drained exclusively into an aneurysmal cerebellar vein. There was no associated venous sinus obstruction. Histopathological examination of the venous sinuses, arteriovenous malformation and venous drainage is described and these findings as they relate to the pathogenesis of dural AVMs are discussed. Vascular malformations of the dura mater do not appear to be a single clinical or pathological entity. The serious risk of hemorrhage from a parenchymal venous aneurysm is emphasized.

With modern imaging techniques, various types of spinal dysraphism are being diagnosed in adults with increasing frequency. We report a 42-year-old woman with diastematomyelia whose symptoms characteristically were precipated by trauma. She exhibited other typical features such as a posterior midline hair patch and vetebral malformations. Metrizamide myelography with computerized tomography showed a bony septum at Tl 1 with a cleft at T9-T11 separating two dural tubes each of which contained a single spinal hemicord. The septum was excised with complete relief of symptoms.

Evoked potentials are the electrical changes that occur in the brain in response to sensory stimuli. They can be recorded from scalp electrodes using sensitive amplifiers. Averaging techniques are necessary to separate the evoked potentials from other electrical activities. Evoked potentials can provide helpful information for the clinical evaluation of neurological patients. They can assess sensory function by demonstrating the brain's response to sensory stimuli. They can localize dysfunction in sensory pathways by showing where and when a sensory response becomes abnormal. They can identify abnormalities of sensory processing that are not apparent during the usual clinical examination. They can assess the extent of normal or abnormal function and thereby assist prognosis in patients with brain-damage.