At least four distinct cerebral diseases — Wernicke-Korsakoff, Marchiafava-Bignami, pellagrous encephalopathy, and acquired hepatocerebral degeneration — have a close association with chronic alcoholism. Each is characterized by a distinctive pathologic change and a reasonably wellestablished pathogenesis; in each the role of alcohol in the causation is secondary. The question posed in this review is whether there is, in addition to the established types of dementia associated with alcoholism, a persistent dementia attributable to the direct toxic effects of alcohol on the brain — i.e., a primary alcoholic dementia. The clinical, psychologic, radiologic, and pathologic evidence bearing on this question is critically reviewed. None of the evidence permits the clear delineation of such an entity. The most serious flaw in the argument for a primary alcoholic dementia is that it lacks a distinctive, well-defined pathology, and it must remain ambiguous until such time as its morphologic basis is established.

Intrinsic rhythmic electrical activity in the brain, such as the hippocampal theta rhythm, might serve important roles in normal cognition. Lesions to the medial septal nuclei, or to the fimbria/fornix, disrupt the hippocampal theta rhythm and lead to memory impairment. We have superimposed an artifical stimulating rhythm to the hippocampus of rats with prior lesion of the fornix, during testing in the Morris water maze. This intervention improves performance in a test of working memory, and lends support to the view that intrinsic rhythmic activity may play an important role in normal physiology, and in certain disease states.

99mTc-HM-PAO single photon emission computed tomography (SPECT) was used to image 30 patients referred for the assessment of dementia. SPECT images revealed various patterns of regional cerebral perfusion (rCBF) in the subgroups of patients with the clinical diagnoses of Alzheimer's disease (AD, n = 14), Pick's disease (n = 1), and multi-infarct dementia (n = 7). In three patients, SPECT clarified the clinical differential diagnostic possibilities. Using a relative rCBF quantification technique, the relationship between specific cognitive impairments and rCBF in the AD patients was determined. There was a significant correlation between language impairment and left hemisphere hypoperfusion, whereas, apraxia correlated with hypoperfusion in the left parietal region. Thus, HMPAO SPECT is useful as an aid in the differential diagnosis of dementia and the technique of relative rCBF quantification with SPECT may contribute to the understanding of the clinico-anatomical relations of cognitive deficits in dementia.

A number of autoimmune diseases and immune-related conditions were investigated in a series of 100 Alzheimer patients and their families. The group was divided into those who had familial dementia of the Alzheimer type and non-familial dementia of the Alzheimer type. HLA DR3 was associated with the familial dementia of the Alzheimer type patients. Adult exposure to tuberculosis appeared to be a risk factor for familial dementia of the Alzheimer type patients. Autoimmune diseases clustered among the non-familial dementia of the Alzheimer type patients, and also among their relatives. Asthma and infertility were also significantly increased among non-familial dementia of the Alzheimer type relatives. The analysis showed that (1) autoimmunity may be important in the sporadic form of Alzheimer disease; (2) it may be possible to confer a decreased risk for Alzheimer disease among relatives when many autoimmune diseases occur in the family; (3) it may be important to assess environmental risk factors for Alzheimer disease separately in patients with familial and sporadic disease; and (4) the efficacy of drug therapies may be dependent on whether the patients have a familial or sporadic form of Alzheimer disease.

An in vitro model of muscle damage was used to investigate the protective effect of mild hypothermia in muscle injury. Rat epitrochlearis muscles were dissected in their entirety and suspended in Krebs-Ringer solution and DNP, a mitochondrial uncoupler, was added. PGE2, and lactate release and the contractile response to stimulation were measured and compared to untreated controls. Experiments were done at 37, 35, 33 and 27°C. At 37°C, DNP stimulated muscle releases large amounts of PGE2 and lactate and is unable to contract. As the temperature is reduced, there is progressive preservation of contractile force, although high lactate levels at the lowest temperatures indicate that the metabolic stress is still present. In contrast, DNP stimulated PGE2 release is completely inhibited at or below 35°C and may be related to a similar protective phenomenon seen in experimental ischemic neuronal death.

Consecutive patients (n = 114), who had single fiber electromyography of the frontalis muscles for symptoms suggestive of ocular myasthenia gravis, were followed up for a mean of 14 months (3-64 mos). At follow up, based on strict criteria, 23 patients were classified as having ocular myasthenia gravis, 8 patients were diagnosed as having mitochondrial myopathy or oculopharyngeal dystrophy, 18 patients were found to have other diseases and 65 patients remained without a definite diagnosis. The single fiber electromyography data of these patients were then reviewed. The patients with ocular myasthenia gravis had, on average, more than 7/20 single fiber pairs with jitter > 45 μs and mean jitter of 56 μs. The 8 patients with mitochondrial myopathy or oculopharyngeal dystrophy had an average of 5/20 single fiber pairs with jitter > 45 μs and a mean jittter of 52 μs and could not be separated from the group with ocular myasthenia gravis on the basis of the single fiber electromyography results. The 18 patients with definite other diagnosis had an average of less than 1/20 single fiber pair with jitter > 45 μs and a mean jitter of 25 μs. This group could be clearly separated from the group with ocular yasthenia gravis. We conclude that single fiber electromyelography is useful in the separation of ocular myasthenia gravis from other causes of oculomotor weakness except mitochondrial myopathy and oculopharyngeal dystrophy.

A retrospective review was undertaken of 139 consecutive patients with presumed carotid artery stenosis referred to a vascular neurosurgeon. The review period included three years prior and one year subsequent to the publication of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) preliminary results showing surgery to be superior to best medical therapy for patients with symptomatic, high grade (> 70% linear diameter) carotid stenosis. The aims of this analysis were to determine any changes in the referral pattern following the NASCET publication (post-NASCET), and to examine the use and reliability for surgical decision making of pre-referral carotid artery imaging. Patient referral rate increased markedly post-NASCET, particularly from neurologists. There was a trend for more post-NASCET referrals to be for high grade stenosis and fewer referrals to be for intermediate grade (30-69% linear diameter) stenosis, although continued referral of patients with intermediate grade stenosis is desirable as randomization into NASCET continues for this group of patients. Ninety-six patients (69%) were referred with carotid duplex ultrasonography having been performed. There was poor correlation of these results with angiography, which remains necessary for planning management. A majority of patients (65%) referred to this surgical practice did not come to surgery.

The prognostic value of magnetic resonance imaging (MRI) in the syndrome of acute transverse myelitis had not been evaluated. After retrospective study of 14 cases, we found that MRI is valuable for both diagnosis and prognosis in this illness. The criteria for the diagnosis of acute transverse myelitis consisted of acute onset (over less than 3 weeks) of symmetrical motor and sensory dysfunction referable to a distinct spinal cord level, with sphincter dysfunction. Patients with abnormal MRIs of the spinal cord had significantly worse outcomes than patients with normal MRIs.

Percutaneous retrogasserian glycerol rhizotomy (PRGR) was used during an 11-year interval in 53 patients with typical trigeminal neuralgia associated with multiple sclerosis. All patients had failed extensive medical trials prior to PRGR. Long-term (median follow-up, 36 months) complete pain relief (no further medication) was achieved in 29 (59%) of 49 evaluable patients. Eight patients (16%) had satisfactory pain control but required occasional medication. Twelve patients (25%) had initial unsatisfactory results with inadequate pain relief; nine underwent alternative surgical procedures. Sixteen patients (30%) subsequently required repeat glycerol rhizotomies to reachieve pain control. Twenty-seven patients (60% of 45 patients evaluated for this finding) retained normal trigeminal sensation after injection. Major trigeminal sensory loss developed in a single patient who had four glycerol rhizotomies over a 25-month interval. No patient developed deafferentation pain. We believe that PRGR is a low-morbidity, effective, and repeatable surgical procedure for the management of trigeminal neuralgia in the setting of multiple sclerosis.

A patient with a remote infarct, seizures, mild hemiparesis, and dysphasia became obtunded over four months and died. Computerized tomography (CT) over 5 years showed a consistent, large, wedge-shaped left hemisphere hypodensity with a central calcification, but without signs of mass effect. This was interpreted as an infarct of the left middle cerebral artery territory. Post-mortem examination of the brain revealed the entire area appearing as infarct on CT was a gliosarcoma. We suspect that the unusual CT appearance of the lesion was likely caused by multiple pathologies: a low grade glioma transforming into a gliosarcoma that was able to spread throughout the area of infarct encephalomalacia without revealing a typical CT appearance of mass effect. The patient's brief period of deterioration probably coincided with transformation of the tumor into a gliosarcoma. The variable CT characteristics of gliosarcomas are reviewed.

The specialty of neurological surgery in this country began when Kenneth G. McKenzie was appointed to the Toronto General Hospital surgical staff in 1924, Canada's first dedicated neurosurgeon. In the years and decades that followed McKenzie and his successors established the Toronto General Hospital as one of the leading clinical and teaching neurosurgical units in the world. It was not without some sadness, therefore, that in 1990 neurosurgery left the walls of the Toronto General Hospital, the service transferred to join with the neurosurgical division of a sister hospital, the Toronto Western, during a merger which created the new, two-site, Toronto Hospital. The following story is of the men and women at the Toronto General Hospital who provided, advanced, and taught neurosurgical care. Many persons, among them orderlies, nurses and physicians, will not receive the mention they deserve in the pages that follow, but are no less remembered.