The pathophysiology of the movement disorders arising from basal ganglia disorders has been uncertain, in part because of a lack of a good theory of how the basal ganglia contribute to normal voluntary movement. An hypothesis for basal ganglia function is proposed here based on recent advances in anatomy and physiology. Briefly, the model proposes that the purpose of the basal ganglia circuits is to select and inhibit specific motor synergies to carry out a desired action. The direct pathway is to select and the indirect pathway is to inhibit these synergies. The clinical and physiological features of Parkinson's disease, L-DOPA dyskinesias, Huntington's disease, dystonia and tic are reviewed. An explanation of these features is put forward based upon the model.

A relationship between epilepsy and damage to mesial temporal structures has long been recognized. Recent advances have clarified somewhat the issue of whether the pathological changes seen in mesial temporal sclerosis represent the cause or the effect of seizures. This paper reviews mesial temporal sclerosis from an historical perspective and summarizes recent developments in the fields of excitotoxicity, selective vulnerability, and synaptic reorganization as they pertain to the pathogenesis of mesial temporal sclerosis.

Proton nuclear magnetic resonance (NMR) spectroscopy was used to examine cerebrospinal fluid (CSF) from patients (n = 30) with actively progressive multiple sclerosis (MS). Metabolite concentrations obtained from the spectra were compared to those determined from the spectra of CSF from control patients (n = 27) with benign spinal disorders. No significant difference was found between the 2 groups for most constituents, including lactate, glutamine, citrate, creatine and creatinine, and glucose. Acetate levels were significantly higher in MS patients, while formate levels were significantly lower, than the controls. There were no significant differences in metabolite concentrations in CSF from early and longstanding MS patients. A peak due to an unidentified compound was found at 2.82 ppm in the spectra of CSF from patients with actively progressive MS, but not in the spectra of CSF from the controls. The peak was not found in spectra of CSF from patients with AIDS dementia complex (n = 9) or Parkinson's disease (n = 5), but it did appear in spectra of CSF from 1 patient with Jakob-Creutzfeldt disease (out of 3 examined) and from 1 patient (out of 7) with Guillan-Barré disease. The unidentified compound is volatile and, from the chemical shift of the observed NMR peak, is probably an N-methyl compound. As such, it may be an intermediate in the cholino-glycine cycle, in which an abnormality has been proposed to exist in MS patients.

As survival rates for childhood acute lymphoblastic leukemia have increased, concerns over improved quality-of-life have also increased. Although 3-10% of children may experience acute transient neurotoxicity during induction chemotherapy, they are felt to be at low risk for late sequelae. We report three previously healthy boys with newly-diagnosed acute lymphoblastic leukemia who presented with obtundation and severe seizures during late induction with a standard four drug chemotherapy regimen. While all three are disease-free survivors, they unexpectedly have persistent and medically intractable partial complex seizures, broad-based neuropsychological impairment and striking neuroimaging abnormalities. These findings suggest that children with leukemia who develop an acute encephalopathy during induction chemotherapy are at risk for long-term neurological and neuropsychological sequelae, despite the cessation of further potentially neurotoxic therapy.

We investigated the serum fatty acid profiles of cholesterol esters, phospholipids and triglycerides in 24 patients with Friedreich's disease and 16 patients with other forms of spinocerebellar degeneration. In 8 patients with Friedreich's disease we also analyzed the fatty acid profile of the lipoprotein fractions. We found no major differences in fatty acid profiles between ataxic patients and sex and age-matched controls; in particular there was no decrease of linoleic acid in Friedreich's disease. The level of linoleic acid in serum cholesterol esters decreased with increasing disability of patients.

In order to determine the usefulness of Computerized Tomography (CT) scanning in making a diagnosis of dementia of the Alzheimer type, a group of patients diagnosed by NINCDS - ADRDA criteria (n = 22) were compared to a group of normal subjects (n = 49) using certain defined linear CT scan measurements. These measurements included specific measurements of the temporal lobes (temporal horns). Subjects were classified correctly 91.5% of the time with a high degree of probability. A diagnostic equation is presented which will allow testing of these methods in a prospective fashion.

There are 60 pediatric neurologists in Canada. Replies were received from 56 in response to a survey regarding the use and perceived value of antiepileptic drug (AED) levels. AED levels are frequently ordered and influence clinical care. There were, however, discrepancies among pediatric neurologists regarding the upper and lower limits of the “therapeutic ranges” and the clinical application of levels. We suggest that both the value and use of AED levels needs further study.

The objective of our prospective study was to assess the role of contact thermography in children with migraine. Contact thermograms were done in 54 children aged 4.2 - 16.5 years (median 10.5 years), who were seen for headache and on 10 age-matched controls, between July and December 1991. Thermograms were interpreted as definitely normal, equivocally normal, equivocally abnormal, and definitely abnormal by a radiologist who was blinded to clinical information. Forty-eight children had the test between headaches; of these, four out of 26 patients (15%) who had migraine without aura and 3 out of 14 children (21%) who had migraine with aura had definitely abnormal thermograms. Nine out of 10 normal controls had definitely normal thermograms. The sensitivity of contact thermography in the diagnosis of childhood migraine, when done between headaches, was low in our study.

Walker-Warburg syndrome is a well delineated clinical entity with characteristic brain and eye anomalies. Recent diagnostic surveys have revealed that muscular dystrophy is an obligatory feature of this syndome. We report a patient with an inflammatory myopathy that preceded dystrophic changes. While reports of parental consanguinity and multiple affected sibships strongly suggest an autosomal recessive genetic basis for this syndrome, previous pathological analyses of the CNS have suggested an inflammatory process. Our case supports both the notion of an aberrant inflammatory process that is likely under genetic control or etiologic heterogeneity (phenocopies) underlying this syndrome.

We report a 77-year-old woman who presented with partial seizures and was found to have an enhancing dural-based parietal convexity mass. The lesion enlarged on serial examination by computed tomography (CT) over a one year period. The clinical features and radiologic appearance were compatible with a pre-operative diagnosis of meningioma; however, pathologic findings were typical of a dural cavernous hemangioma. Accumulating evidence suggests that these lesions are an uncommon but distinct type of vascular malformation most often arising from the cavernous sinus, tentorium, or cerebello-pontine angle. With CT, magnetic resonance imaging and angiography, these lesions can closely resemble meningioma in terms of signal characteristics, enhancement pattern, and location. This is of importance both in the practical management of meningiomas where the diagnosis is often based on radiologic studies alone, and in clinical trials where incorrect entry diagnosis should be avoided.

Paralysis induced by neuromuscular blocking agents facilitates ventilation of seriously ill patients but may preclude clinical recognition of seizures. We describe the occurrence of severe cognitive impairment in a 14-year-old girl in whom status epilepticus was recognized only when pancuronium was withdrawn after 14 hours of paralysis. This patient emphasizes a potential danger of paralysis from drugs in patients with acute cerebral dysfunction.

We describe a young man who, shortly after exposure to moldy silage, developed a neurological syndrome consisting of dementia and a remarkable tremor which was precipitated by movement. All symptoms resolved within one week. Despite investigation, no definitive diagnosis was reached. We propose that this patient's illness may have resulted from inhalation exposure to a tremorgenic mycotoxin.

A 41-year-old woman with a history of birth injury to the brachial plexus suffered several delayed episodes of neurological deterioration. Magnetic resonance imaging studies revealed a syrinx extending from the conus medullaris into the brainstem and rostrally into both internal capsules. She died of an acute exacerbation of chronic respiratory failure. Autopsy demonstrated syringomyelia and syringobulbia with cavity extension bilaterally along the corticospinal tracts into the internal capsules. Islands of glial tissue in the subarachnoid space around the medulla caused obstruction of the subarachnoid space at the foramen magnum. These were probably the result of birth injury to the cerebellum. A detailed clinico-pathological correlation is provided to explain her neurological deficits. The pathogenesis of syrinx formation is discussed in terms of a late manifestation of birth trauma.

The nature of the human mind is addressed from a neurological viewpoint. First from reported observations on subjects born blind with congenital cataract, who acquired vision after surgery, the concept of the primacy of somatosensation is developed. Therefrom some principles of the organization of higher sensory functions in the dominant parietal, occipital and temporal lobes are deduced. Sentience is traced to somatosensation. Some characteristics of the mind and of thinking are described. The non-existence of the unconscious is inferred. The question of free will is approached. Using neurological experience it is demonstrated that a good case for operation of a free will is difficull to establish. Positing the absence of a free will may be beneficial in the analysis and management of behavior. Finally the opportunity to study the nature and mechanism of the emotions in clinical neurology is outlined.

After just completing his neurosurgical training in 1954 Dr. William Horsey visited Queen Square, England, where on one occasion he attended a pathological conference discussing a young man who had died from complications following biopsy of a low grade astrocytoma. One of the surgeons present, none other than the brilliant, mercurial and sometimes flamboyant Wylie McKissock, asked young Horsey what he thought of the case. What followed was not the primitive, colonial opinion that might have been expected. Unintimidated, Dr. Horsey said that he probably would not have operated on the man in the first place, since he was neurologically well-preserved bearing an intrinsic tumor causing minimal deformity of the ventriculogram. But if he had operated, Horsey went on, he would have finished the job with a proper decompression of the affected temporal lobe, rather than just a biopsy. And, he continued, if he had made the decision to treat this young man's tumor, he would also have treated his postoperative clot, with a second operation, to save the patient's life. It was this kind of sharp intelligence and sensibility, which so silenced a crowded Queen Square conference room that morning, combined with a superb operating technique and a particular dedication to teaching that characterized Bill Horsey's neurosurgical career.