Hoffmann (H) reflexes were elicited from the soleus muscle during treadmill walking in 21 spastic paretic patients. The soleus and tibialis anterior muscles were reciprocally activated during walking in most patients, much like that observed in healthy individuals. The pattern of H-reflex modulation varied considerably between patients, from being relatively normal in some patients to a complete absence of modulation in others. The most common pattern observed was a lack of H-reflex modulation through the stance phase and slight depression of the reflex in the swing phase, considerably less modulation than that of normal subjects under comparable walking conditions. The high reflex amplitudes during periods of the step cycle such as early stance seems to be related to the stretch-induced large electromyogram bursts in the soleus in some subjects. The abnormally active reflexes appear to contribute to the clonus encountered during walking in these patients. In three patients who were able to walk for extended periods, the effect of stimulus intensity was examined. Two of these patients showed a greater degree of reflex modulation at lower stimulus intensities, suggesting that the lack of modulation observed at higher stimulus intensities is a result of saturation of the reflex loop. In six other patients, however, no reflex modulation could be demonstrated even at very low stimulus intensities.

Cerebral blood flow (CBF) and central conduction time (CCT) were recorded from 58 subarachnoid hemorrhage patients and from 49 age-matched controls. CBF was calculated following Xenon inhalation and CCT was determined from somatosensory evoked potentials (SSEP's) following median nerve stimulation. Each patient had a CT scan on the day of admission which was graded from I-IV. CBF, CCT and neurological grade (Hunt and Hess classification) were concomitantly recorded 1, 4, 7 and 14 days after subarachnoid hemorrhage. Mean CBF was highest in patients with neurological grades I and II (48.6 ± 12.3 and 48.1 ± 10.3 ml/lOOgm/min respectively) and lowest in patients with neurological grade IV (37.3 ± 9.6 ml/lOOgm/min). Patients in neurological grade I or II had mean CBF and CCT measurements that were significantly different from those obtained from patients in neurological grade IV (P < 0.05). Neurological grade and CT scan grade correlated with CBF (P < 0.0001) better than CCT (P = 0.015). Unexpectedly low CBF's from patients in neurological grades II and III (< 37 and < 31 ml/lOOgm/min respectively) failed to significantly prolong CCT suggesting CCT is unable to detect marginal ischemia. A significant correlation between CBF and CCT occurred only when CBF was < 30 ml/lOOgm/min (R = 0.75, P = 0.05). It appears that prolonged CCT is associated with a drop in CBF only when CBF drops below a certain threshold.

A group of 57-head injured patients showing computerized tomographic (CT) findings compatible with “diffuse brain injury” or of the so called “diffuse axonal injury” is analyzed. Thirty-four patients showed intraparenchymal hemorrhage in the CT scan study, 8 intraventricular hemorrhage and 15 patients had both intraparenchymal and intraventricular hemorrhage. Forty percent (23/57) of those with these findings had associated intracranial focal lesions. The deep nuclei are the most common location of intraparenchymal hemorrhage. Signs of brain stem hemorrhage were seen in 9 patients. Forty-nine percent of patients in this series had a good outcome. Old age (>60), abnormal motor response, abnormal eye signs, associated with focal lesions, and evidence of brain stem hemorrhage are reliable prognostic parameters for a grave outcome.

Transsphenoidal surgery is currently performed extensively for lesions of the sella turcica. The mortality and morbidity of this surgical approach are minimal, and the results satisfactory overall. Only a few studies have addressed the complications of this approach. The authors present a retrospective study of 200 transsphenoidal procedures in 196 patients over an eleven year period. There was one death due to meningitis. Major morbidity consisted of intraventricular hemorrhage in three patients, false aneurysm of the internal carotid artery in one patient and thalamic infarction in another patient. Minor morbidity details are presented. The pathogenesis of the most serious of these complications along with possible preventive measures are discussed.

The safety and efficacy of Sinemet® CR, a controlled-release formulation of carbidopa/levodopa, were investigated in a three year, open-label trial involving 18 parkinsonian patients with fluctuating motor response. The average daily levodopa dosing frequency did not change significantly during long-term treatment. Efficacy measures generally revealed a gradual progression of parkinsonian disability. Patient diaries of motor fluctuations revealed relative stability of time “on” but with a tendency toward increased time “on with dyskinesias” over the 36 month followup period. There were no adverse laboratory results deemed to be related to Sinemet® CR and no unexpected side effects were observed.

Inter-observer agreement was evaluated for twelve items used in the neurological assessment of comatose children. Data were obtained prospectively on fifteen patients examined independently by two observers in a double-blind fashion. Observer variability was measured by using the Disagreement Rate and Kappa statistic. The Disagreement Rate ranged from 0.01 to 0.12 for all items. Values for Kappa statistic were generally in accordance with those for Disagreement Rate. The data suggest fair to almost perfect inter-observer agreement for the items used to assess comatose children in this study.

Performance on an eye-hand tracking task and a multi-joint reaching movement to a visual target was studied in a patient with stable cerebellar ataxia and in control subjects. The patient subsequently died and a full neuropathological examination was performed. The neuropathological findings were similar to those seen in patients with paraneoplastic cerebellar degeneration, but no tumor was found at autopsy eight years after onset of the patient's cerebellar syndrome. A severe cerebellar cortical degeneration with complete Purkinje cell loss was demonstrated, whereas cerebellar nuclei and brainstem structures showed no neuronal loss. Tracking performance by the patient was characterized by abnormally large numbers of high velocity movements and hand direction reversals, and by excessive lagging of the hand behind the target in time. In the multi-joint reaching movement, the patient showed a delay in movement onset at the elbow joint compared to movement onset at the shoulder joint. The velocity profile of the movement at the shoulder joint was abnormal. The duration of the acceleration phase was poorly correlated with both peak angular velocity and the duration of the deceleration phase. One of the most striking findings was the inability of the patient to consistently produce the same movement direction from trial to trial while reaching to the same target. Our data suggests that the cerebellar cortex is involved in multiple aspects of motor control including visuomotor integration mechanisms.

Two additional patterns, minuscule 28 per second positive spikes and huge N-shape potentials, have been identified exclusively in the EEGs of patients with 14 and 6 per second positive spikes. They occur predominantly during drowsiness and light sleep, usually in children, seldom in young adults. Their presence adds little to the clinical relevance of positive spikes. Familiarization with the N-shape potentials — the commoner of the two patterns — is important, lest they are mistaken for interictal abnormalities of significance such as atypical spike-wave complexes.

3-Nitropropionic acid (3-NPA) — a suicide inhibitor of succinate dehydrogenase — is a widely distributed plant and fungal neurotoxin known to induce damage to basal ganglia, hippocampus, spinal tracts and peripheral nerves in animals. Recent reports from Northern China indicate that 3-NPA is also likely to be responsible for the development of putaminal necrosis with delayed dystonia in children after ingestion of mildewed sugar cane. This article discusses the role of 3-NPA in the causation of the disease in China, its neurotoxic effects in animals and the potential role for this compound as a probe of selective neuronal vulnerability.

Cerebral arteriovenous malformations (AVM), regardless of the mode of discovery, have an annual risk of hemorrhage of approximately 4 percent. A progressive obliterative vasculitis culminating in the occlusion of an AVM may be induced by the administration of radiation doses of approximately 20 Gy given in a single fraction. The process takes about two years and occlusion occurs in approximately 80% of patients so treated. Such a dose may be accurately administered to AVMs up to 3 cm in diameter with very little radiation imparted to the adjacent brain by means of multiple highly collimated radially arranged cobalt sources (the Gamma Knife) or by means of a modified linear accelerator turned through an arc or arcs with the target AVM as the centre of rotation. The Gamma Knife and the modified linear accelerator have nearly equal accuracy. Recent experience with modified linear accelerators indicates efficacy equal to the Gamma Knife. Both devices are effective treatment for small AVMs but the cost of modifying a pre-existing linear accelerator is only a few percent of the acquisition and installation costs of the Gamma Knife.

We describe a young man with a two and a half year history of idiopathic irregular contractions of an antitragicus muscle in the absence of a more generalized movement disorder. These contractions persisted in sleep and could not be replicated voluntarily. Because proximal nerve block temporarily eliminated the movements and complex hand movements reduced their amplitude and frequency, we suspect a central generator. However, these movements were not associated with any known pathologic condition.

Rupture of cerebral aneurysms is an important cause of morbidity and mortality in patients with adult polycystic kidney disease (PKD). In the present paper, we review the literature regarding the association of cerebral aneurysms and PKD and emphasize, by means of a case report, the importance of familial clustering of aneurysms in patients with PKD. We conclude that the prevalence of intracranial aneurysms in patients with PKD approaches 40% and is likely significantly higher in patients with PKD and a positive family history for cerebral aneurysm. We recommend that screening cerebral angiography be strongly considered in all patients with PKD and a family history of cerebral aneurysm or subarachnoid hemorrhage.

A patient who presented with bilateral loss of all pupillary reactions and normal ocular motor function is reported. Investigation revealed the presence of massive hydrocephalus. The syndrome developed shortly after transsphenoidal surgery for a suprasellar craniopharyngioma. Pupillary function returned to normal following the insertion of a ventriculo-peritoneal shunt. It is suggested that the syndrome was due to compression of the visceral oculomotor nuclei by a dilated sylvian aqueduct.

Intracranial venous sinus thrombosis is an uncommon cause of pseudotumor cerebri. The diagnosis is often not confirmed on the rationale that treatment will not be altered. We report a case presenting a pseudotumor cerebri where the underlying pathology disclosed dural sinus thrombosis resulting from compression by an eosionophilic granuloma of the occipital bone. Routine CT of the head and Technetium-99m brain scan initially demonstrated neither tumor nor thrombosis. Plain skull x-rays subsequently revealed a lytic lesion of the occiput. When reinvestigated with CT using bone density windows the tumor was revealed. Excision of the tumor and a short course of cobalt therapy was curative. Special techniques in nuclear scanning, CT and MRI designed to improve the sensitivity for diagnosing venous sinus thrombosis are described. This case illustrates the importance of establishing a definitive diagnosis and shows the importance of pre-test consultation between clinicians and radiologists to ensure that specific investigative techniques are properly utilized.

The authors present a case of a 29-year-old man who developed rapidly progressive cranial nerve palsies and a right hemiparesis secondary to a pontine hemorrhage. The rare but correct diagnosis of a clival chordoma which had invaded the brain stem and subsequently hemorrhaged was based on computed tomography and magnetic resonance imaging. The diagnosis was confirmed at surgery when the patient underwent a successful operative decompression of tumor and clot from the pons via a sub-occipital craniotomy. This represents the first case of a clival chordoma to hemorrhage into the brain stem, which was diagnosed preoperatively and the patient survived.