This paper is directed primarily to clinicians who diagnose and treat patients with neurological disorders. It is an attempt to illustrate that even with modern imaging technology and other advances in laboratory testing, a thorough understanding of neurophysiology and its anatomical substrate still plays an important role in the diagnosis and management of patients with neurological diseases. One area in neurophysiology in which there has been great progress in the last few decades is the ocular motor system. Particular interest has been focused on the ways that the brain can adapt to lesions, and more specifically, how the ocular motor system keeps itself calibrated in the face of normal development and aging as well as in response to disease and trauma. Since disorders of eye movements are such common and often dramatic manifestations of neurological disease it seems appropriate to bring some of the newer concepts in ocular motor physiology to the “bedside”.

With the development of modern imaging techniques, disturbances of neuronal migration appear to be a major cause of epilepsy, mental retardation and chronic neurological disability in childhood. Sixty-nine cases are presented, including 46 of diffuse migration abnormalities and 23 of localized dysplasia. Patients with diffuse migration disorders presented with mental retardation, gross motor impairment and severe seizure disorders whereas in those with focal anomalies, epilepsy was the chief complaint. Magnetic resonance imaging, although usually diagnostic of migration disorders often does not allow definition of the pathologic type. Some EEG patterns, such as high amplitude fast rhythms or the theta-delta pattern are highly suggestive. Most cases of abnormal migration are sporadic and probably acquired. Some are due to chromosomal anomalies, especially of chromosome 17p where a gene for lissencephaly has been mapped. Familial cases occur with both recessive and possibly dominant inheritance. Epilepsy due to migration abnormalities is often intractable. Resection of dysplastic cortex may be effective for localized disease and callosotomy has been proposed for diffuse anomalies.

We studied the influence of sulindac, a nonsteroidal anti-inflammatory agent on experimental streptozotocin-induced diabetic neuropathy. Untreated diabetic rats were compared with nondiabetic rats, diabetic rats treated with low dose insulin and diabetic rats given sulindac (6.0 mg/kg by gavage 5 of 7 days weekly). Neuropathy was assessed by following serial in vivo motor and sensory caudal conduction, resistance to ischemic conduction failure, and in vitro conduction in sural myelinated and unmyelinated sensory fibers. The impact of low dose insulin and sulindac treatment on the microenvironment of the L4 dorsal root ganglion and sciatic endoneurium was asssessed by measuring local perfusion and oxygen tension after 16 weeks of diabetes. Sulindac normalized conduction velocity in caudal sensory fibers, sural myelinated fibers and sural unmyelinated fibers, and reduced the number of diabetic cataracts. Sulindac also normalized a deficit in dorsal root ganglion blood flow and a reduction in sciatic endoneurial oxygen tension in diabetic rats. Low dose insulin improved neuropathy as well but the pattern of benefits was less robust than that of sulindac. Sulindac may be a candidate for a clinical trial in human diabetic polyneuropathy.

We describe eleven mid-western Canadian aboriginal infants with a unique, progressive muscle disorder. All except one had muscle biopsy and/or autopsy. The infants were normal newborns who rapidly developed rigidity of all skeletal muscles, with early, respiratory insufficiency. Death occurred before 18 months of age. Electromyography showed increased insertion activity and profuse fibrillation potentials; motor unit potentials and interference pattern are normal until late in the course. Pathologic features include progressive, granular to powdery Z-band transformation, myofibrillar loss, and muscle regeneration. SDS-gel electrophoresis of one muscle sample revealed increased 54kDa and reduced 80kDa protein fractions. This disease differs from other conditions with Z-band alterations because of continuous muscle activity and relentless clinical progression. The clinical features, elevated serum creatine kinase, electromyographic and muscle biopsy findings suggest a dystrophic process. The recognition of this condition as an autosomal recessive disorder allows appropriate genetic counselling.

Complications were examined in a single surgeon’s series of 207 consecutive adult patients undergoing first craniotomy for intra-axial brain tumour. The study group consisted of 114 gliomas, 74 metastatic tumours and 19 miscellaneous lesions. There were 25 infratentorial tumours and 182 supratentorial tumours (39 deep and 143 superficial). The total number of patients sustaining complications was 52 for an overall complication rate of 25.1%; the rate was higher for infratentorial tumours (44.0%) than supratentorial tumours (22.8%) regardless of histology (p = 0.012). There were 5 deaths for a mortality rate of 2.4%. Forty-seven patients incurred operative morbidity (22.7%); 7 out of the 47 had multiple complications. Sixteen patients sustained transient worsening due to edema (7.7%) and 6 patients sustained permanent neurological deficit (2.9%). Medical complications were suffered by 17 patients (8.2%). Major complications which significantly altered the quality and/or quantity of survival were suffered by 9 patients overall (4.3%).

The purpose of this study was to explore the relationship between neurologic function, using a quantitative measurement of continuous somatosensory evoked potentials (SSEPs), and intracranial pressure (ICP) following traumatic brain injury. During a 6 year period, severely head-injured patients with a Glascow Coma Scale ≤ 8 who were not moribund were monitored with SSEPs and ICP measurements. SSEPs from each hemisphere and ICP were recorded hourly for each patient. Neurologic outcomes were scored using the Glasgow Outcome Scale at three months post injury. Although initial SSEP amplitude did not correlate well with outcome, final SSEP summed peak to peak amplitude from both hemispheres (p = .0001), the best hemisphere (p = .0004), and the worst hemisphere (p = .0001) correlated well with the Glasgow Outcome Scale groups. Of a total of 72 patients, 40 had deteriorating SSEPs and 32 had stable or improving SSEPs. Peak ICP values were not statistically different in these groups (p = .6). Among patients with deteriorating SSEPs, 52.5% lost the greatest proportion of hemispheric electrical activity prior to ICP elevation. In the remaining patients, the percent reduction of SSEP activity after peak ICP levels was not statistically different from the percent reduction in SSEP activity prior to the peak ICP levels (p = .9). This data suggests that in a select group of patients with severe head injury, ICP does not cause SSEP deterioration, but rather is the consequence of deterioration of brain function.

Recent brain research proposes that, during ischemia, synaptically released excitatory amino acid neurotransmitters accumulate at toxic concentrations with ensuing neuronal death. Their action is mediated by the receptor subtype N-methyl-D-aspartate (NMDA). The protective effect of NMDA receptor blockade with intrathecal MgS04 and MK-801 was investigated during spinal cord ischemia induced by aortic occlusion of 12 minutes. Male Sprague-Dawley rats, 250-300g, underwent intrathecal administration of 20 μL of normal saline (SA n = 16), MgS04 1M (MG n = 16), or MK-801, 25 mM solutions (MK n = 16) in a randomized order. After 2 hours, the animals underwent occlusion of the thoracic aorta and subclavian arteries for 12 min. An additional control group (CO n = 16) underwent occlusion for 12 minutes, without intrathecal injection. The animals were scored according to their functional performance (LS = lesion score) each day for four days by a blinded observer. Mean LS were calculated for each group at a given day. Treatment and control groups were not different at day 1 (P = 0.302). Group MG was improved from groups SA (P = < 0.0039) and CO (P = < 0.0048) at day 4. This study demonstrates that although intrathecal NMDA receptor blockade with MgS04 or MK-801 does not prevent paraplegia due to spinal cord ischemia in the rat, it could however influence the rate of recovery after ischemic injury.

The organization of the primary somatosensory cortex innervated by the ulnar nerve was studied before and immediately after ulnar nerve transection in 11 cats electrophysiologically mapped under Nembutal or Ketamine anesthesia. The cortex was reexamined a second time beginning 42 hr after nerve transection in four cats anesthetized with Nembutal. One additional sham-operated control was also mapped. The region of cortex formerly served by the ulnar nerve remained largely unresponsive to somatic stimulation independent of the type of anesthetic used during recording. Nonetheless, animals anesthetized with Ketamine had more new responsive sites in deafferented cortex following nerve cut than cats anesthetized with Nembutal. New responses, when observed, were evoked by stimulation of a region of skin adjacent to the region served by the ulnar nerve. These findings suggest that the immediate response to deafferentation of somatosensory cortex is a limited acquisition of novel responses restricted to a region immediately adjacent to cortex containing normal afferent input.

The ability to analyze the genotype of deceased affected members of pedigrees segregating inherited neurological diseases considerably augments the informativeness of such pedigrees. This information has direct application in attempts to isolate disease genes by positional cloning strategies, and for genetic counselling. We show that the genotype at polymorphic simple sequence repeat loci can be determined from genomic DNA isolated from 10 micron thick paraffin embedded, formalin fixed neurological tissues. The critical constraint on this method is the size of the template target bearing the simple sequence repeat, which should ideally be less than 165 base pairs.

Fifty-four per cent of 41 chronically institutionalized adult patients with epilepsy had ataxia of gait (wide mean stride width). None of the following correlated with stride width: serum phenytoin, previous phenytoin toxicity, seizure frequency, or status epilepticus. Seventeen of the 41 patients had computed tomographic head scans. Patients with radiological evidence of cerebellar atrophy had a wider mean stride width, later age of onset of seizures, greater peak serum concentrations of phenytoin than did those without cerebellar atrophy. Ataxia of gait was inconsistently associated with cerebellar atrophy. Elevated serum/plasma concentrations of phenytoin may be a risk factor for cerebellar atrophy, but seizure frequency or status epilepticus are not independently related to this complication.

The use of the combination of fluoxetine, an anti-depressant serotonin uptake inhibitor, and selegiline, a monoamine oxidase -B inhibitor, was reviewed in a large population of patients with Parkinson’s disease. All records were reviewed from a Parkinson’s disease clinic to determine how many patients were treated simultaneously with selegiline and fluoxetine. Patient characteristics, duration and dose of treatment, side effects and reasons for discontinuation were noted. Twenty-three patients received both medications at the same time. No additional side effects were noted with the combination therapy that had not already been reported with each medication alone. No serious side effects were found. In this clinic population, fluoxetine and selegiline were used in combination without major side effects, but further observation is warranted.

Reports of a high prevalence rate for multiple sclerosis in Southern Alberta led to an epidemiologic study of this disease in the Crowsnest Pass and Cardston regions. In Cardston, the prevalence rate for multiple sclerosis was 88 per 100,000. In the Crowsnest Pass, the prevalence rate was 217 per 100,000. Previous epidemiologic studies of the prevalence rate of multiple sclerosis in Western Canada have shown rates between 93 and 111 per 100,000. Two prevalence studies of multiple sclerosis in Barrhead County, Alberta and Westlock County, Alberta show prevalence rates of 196 and 201 per 100,000. The prevalence rate in the Crowsnest Pass is comparable to the prevalence in Barrhead County and Westlock County, Alberta. However, there is no statistically significant difference between prevalence rates in the Cardston and Crowsnest Pass regions and our overall feeling is that the results of studies of small populations should be interpreted with caution.

We present the results of a randomized double-blinded placebo controlled, multicenter trial, of low-dose mitoxantrone (MX), after one year, in 25 patients with relapsing-remitting multiple sclerosis, who had serial enhanced magnetic resonance imaging (MRI). Treatment groups were balanced for age, gender, duration of illness and neurological disability. Five of the 13 MX patients and 10 of the 12 placebo patients had exacerbations during treatment (p < 0.02). The mean change in the extended disability status scale was not significantly different between the MX and placebo treatment groups. Serial Gadolinium-DTPA enhanced MRI detected no significant difference between the MX treated and placebo groups in the mean total number of new, enlarging, or Gadolinium-DTPA enhancing lesions; there was a trend toward a reduction of new, enlarging and Gadolinium-DTPA enhancing lesions in MX patients. Despite this ameliorating effect, the results indicate that serial Gadolinium-DTPA enhanced MRI, performed over one year in a limited number of patients, could not provide conclusive evidence for a role of MX therapy in relapsing-remitting multiple sclerosis.

We describe a 31-year-old man with clinically definite multiple sclerosis who presented with intractable hiccup for one month prior to admission. The responsible lesion was confirmed by magnetic resonance imaging to be a plaque in the ventral paramedian portion of the medulla oblongata.

A 9-month-old male presented to hospital with signs and symptoms of raised intracranial pressure. A CT scan showed obstructive hydrocephalus from a large pineal region mass lesion into which an intratumoral hemorrhage had occurred. A posterior fossa craniectomy and subtotal excision of the mass lesion were performed. By histopathology, the lesion was a malignant rhabdoid tumour (MRT). Despite surgery and chemotherapy, the tumour grew inexorably, and the patient died four months after the initial diagnosis. MRT is a rare and highly invasive neoplasm which infrequently arises from the central nervous system. This is the first documented case of a MRT arising from the pineal region. The clinical, radiographic, and pathological features of the MRT in this patient are presented.

Part 1 of this two part series outlined the beginning of Canadian neurosurgery and neurosurgical training at the Toronto General Hospital under Kenneth G. McKenzie, and described the efforts of E. Harry Botterell, McKenzie’s neurosurgical trainee and successor, in establishing the Toronto school of neurosurgery. This second part reviews the course of neurosurgery at the Toronto General until the creation of The Toronto Hospital.

In June 1993, the Canadian Neurological Society (CNS) at its annual meeting passed a motion to join the Royal College of Physicians and Surgeons of Canada (Royal College) MOCOMP program. A MOCOMP (Maintenance of Competence) Sub-Committee of the CNS Education and Manpower Committee has also been established to deal with implementation issues, and to liaise with the Royal College. These are important milestones, and it is important that the momentum which has brought our national specialty society to full participation in the Royal College MOCOMP program be maintained.