One hundred consecutive patients between 1961 and 1980, with temporal lobectomy including excision of half or more of the hippocampal formation, have been analyzed for degree of reduction of seizures. Thirty-nine percent have become and remained seizure free for follow-up period of 2 to 24 years (median 12 years). Another 24 patients achieved a marked reduction in seizure tendency as defined in the report and 25 showed a lesser degree of improvement. In fifteen patients no change in seizure frequency was recorded. Thus in this series of 100 patients, a complete or marked reduction of the seizure tendency was achieved in 63%.

Tay-Sachs disease is one of the few neurodegenerative diseases of known cause. It results from mutations of the HEXA gene encoding the a subunit of β-hexosaminidase, producing a destructive ganglioside accumulation in lysosomes, principally in neurons. With the determination of the protein sequence of the α and β subunits, deduced from cDNA sequences, the complex pathway of subcellular and lysosomal processing of the enzyme has been determined. More recently, detailed knowledge of the gene structure has allowed the determination of specific mutations causing Tay-Sachs disease. The high incidence of the disease in Ashkenazi Jews is attributed predominantly to three mutations present in high frequency, while in non-Jews some two dozen mutations have been identified thus far. The cataloguing of mutations has important implications for carrier screening and prenatal diagnosis for Tay-Sachs disease.

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.

The evidence for the role of the amygdala in temporal lobe seizures is supported by this follow-up (2-20 years) of 100 patients who were treated surgically by excision of the antero-lateral temporal cortex, most or all of the amygdala and minimal resection of the hippocampus. The findings showed 53 patients seizure-free or with rare or occasional seizures, 10 patients with marked seizure reduction and 37 with moderate or less reduction of seizures. The results are the same as in another 100 patients where, in addition, half or more of the hippocampus was resected.

β-amyloid protein, a 42-43 amino acid polypeptide, accumulates abnormally in senile plaques and the cerebral vasculature in Alzheimer's disease. This polypeptide is derived from a membrane-associated precursor which has several isoforms expressed in many tissues. The precursor protein is processed constitutively within the P-amyloid domain, leading to the release of the large β-terminal portion into the extracellular medium, β-amyloid protein may be toxic to certain neuronal cell types and its early deposition may be an important event in the pathogenesis of Alzheimer's disease.

Most patients with brainstem hemorrhage have a poor prognosis. There are occasional reports of a favorable outcome with hematomas restricted to the mid-brain region. We report two patients with hematomas within the lower brainstem (pons and medulla) who made a good recovery. Diagnosis was unsuspected until the cranial CT scan was done. Angiography was normal in both cases. Recovery was excellent in one and fair in the second patient. Patients with medullary hemorrhage are at risk for aspiration and may suddenly develop respiratory arrest and therefore should be carefully observed. Our review of the literature suggests that with some small brain-stem hemorrhages recovery is good to excellent and recurrences are rare.

Follow-up data of 2 to 49 years' duration are presented on 257 patients with cortical excisions for non-tumoral frontal lobe epilepsy. Twenty-six percent have become and remained seizure free. Another 30% have had a marked reduction of seizure tendency. Thus a total of 56% have had a long term complete or marked reduction of seizure tendency after the cortical resection. The cortical resections were classified into 5 regional categories. Forty-seven percent of patients with anterior frontal resections were in the seizure free category, as were 35% of patients with excisions limited to the convexity cortex and 32% of patients with maximal or near maximal frontal lobectomy. Only 18% of patients with frontal parasaggital excisions were in the seizure free category, and 10% of the patients who had excision of frontal cortex plus limited excision of adjacent central and/or temporal cortex.

A National Conference on Parkinson's disease was held on September 7th-8th, 1990 in Victoria, British Columbia. The scientific program included 11 formal presentations, 10 small group workshops and video presentations of interesting examples of movement disorders. The subjects discussed ranged from epidemiology and etiology to current and possible future modes of management of Parkinson's disease.

The monthly intracisternal inoculation of young adult New Zealand white rabbits with low-dose (100 Μg) aluminum chloride induces aggregates of phosphorylated neurofilament that mimics the intraneuronal inclusions of amyotrophic lateral sclerosis. The chronic progressive myelopathy and topographically-specific motor neuron degeneration that occurs in the absence of suppressions of neurofilament messenger RNA levels in this model contrasts with the acute fulminant encephalomyelopathy and nonspecific gene suppressions that occur subsequent to high-dose (1000 Μg) aluminum chloride inoculations. Further analysis of this unique model of chronic motor system degeneration can be expected to provide additional insights into the pathogenesis of amyotrophic lateral sclerosis.

The course of a patient with an olfactory neuroblastoma treated with conventional doses of chemotherapeutic agents and radiotherapy is presented. The patient survived 34 months after tumour necrosis with resultant pneumocephalus requiring surgical intervention.

Motor neuron diseases selectively produce degeneration and death of motor neurons; the pathogenesis of these disorders and the specificity for this population of neurons are unknown. Hereditary Canine Spinal Muscular Atrophy produces a lower motor neuron disease which is clinically and pathologically similar to human motor neuron disease: motor neurons dysfunction and degenerate. The canine model provides an opportunity to investigate early stages of disease when there are viable motor neurons still present and might be responsive to a variety of therapeutic interventions. The canine disease, like the human disease, is inherited as an autosomal dominant. The extensive canine pedigree of more than 200 characterized individuals permits genetic analysis using syntenic linkage techniques which may identify a marker for the canine trait and provide insights into homologous regions for study in human kindreds.

Patients with epileptogenic lesions that are more or less restricted to the central, parietal or occipital regions represent 14% of our total epilepsy surgery series and consisted of 322 patients at the end of 1980. Tumoral or major vascular lesions were present in 117 patients (37%), but this report is limited to the remaining 203 patients (63%) with non-tumoral epileptogenic lesions. The presumed etiology was birth trauma or anoxia in 25%, postnatal brain trauma in 25%, and unknown in 24%, miscellaneous lesions were present in 16%, post-inflammatory gliosis or multiple factors were present in the remaining 10%. Follow-up data of 2-51 years' duration (median 18 years) are available for 186 of these 203 patients. Sixty-three patients (34%) remain seizure-free. Forty-two patients (23%) have a marked reduction of seizures. The remaining 81 patients (44%) have a lesser reduction. The variation in clinical seizure patterns is considerably greater than in temporal lobe epilepsy. Focal sensorimotor phenomena are common at the onset, whether the seizures begin in the central region or further posterior. The success following cortical resection is equally gratifying and the failures just as distressing as in surgery for epilepsy involving other brain regions.