The American Heart Association carotid endarterectomy (CE) guidelines endorse CE for asymptomatic carotid stenosis if the procedure can be performed with low morbidity. However, the Canadian Stroke Consortium has published a consensus against CE for asymptomatic stenosis. The views of practicing neurologists in the two countries on this subject are unclear.

A survey was undertaken of 270 neurologists from either Florida or Indiana and 180 neurologists from either Ontario or Quebec.

The survey was returned by 36% of neurologists. Both Florida (65%) and Indiana neurologists (35%) were significantly more likely than Canadian neurologists (11%) to sometimes/often refer patients for surgery(p<0.001). Neurologists from Florida relied more on noninvasive methods of carotid stenosis assessment (36%) than Canadian neurologists (12%, p=0.003), who preferred angiography. Neurologists from Florida more often cited medicolegal concerns as a reason for referring patients for surgery (27%), compared to Canadian neurologists (3%, p=0.0001).

Practices pertaining to carotid stenosis evaluation and management differ both regionally and by country. Canadian neurologists refer fewer asymptomatic patients for CE and rely more on angiography as a preoperative diagnostic tool. The potential of medicolegal liability is a greater force in clinical decision-making for certain U.S. neurologists, compared to their Canadian counterparts. These differences may partly explain the variations in CE utilization in the two countries.

A preliminary national survey of ischemic stroke in the young (15-45 years) undertaken by the Canadian Stroke Consortium indicated that in 44% of 356 patients, no cause was found.

To determine the reason for this high incidence of diagnostic uncertainty in young patients with ischemic stroke.

Neurologists in the ten Canadian stroke centers completed a detailed questionnaire for patients aged 15-45 years admitted to hospital between January 1993 and December 1997. Using a step-wise diagnostic algorithm incorporating clinical, neuroimaging, neurovascular and laboratory data, we divided patients into three groups: (1) those with established cause for the ischemic stroke, (2) those who remained unexplained despite adequate investigation, (3) those who remained unexplained but were, in our opinion, under-investigated.

In 197 patients (56%), an identified cause was established including cardioembolic sources (14%), extracranial arterial dissection (13%), lacunar infarcts (8%) atherosclerosis (6%). A miscellaneous group of 15%, included cerebral venous thrombosis, coagulopathies, vasculitis and others. In 159 patients (44%) with no apparent cause for their stroke, we considered only 81 (23%) adequately investigated, and 78 (21%) inadequately investigated.

About one in five young patients was inadequately investigated by a stroke-oriented group of neurologists. The major problem appears to be restriction of investigations to neuroimaging alone (usually computerized cerebral tomography), without further tests such as cerebral angiography and cardiac imaging.

There have been many reports of percutaneous radiofrequency facet rhizotomy, perhaps better referred to as facet denervation, usually performed under general anaesthesia, with inconsistent success rates.

To report the authors' outcome data using both general and local anaesthesia and to reassess the value of this controversial procedure.

Our experience with 118 consecutive percutaneous radiofrequency facet rhizotomies performed on 90 patients in the Toronto Western Hospital was analyzed. Sixty percent of the procedures were performed under general anaesthesia, 40% under local anaesthesia. All patients had been temporarily virtually relieved of pain after local anaesthetic blockade of the subject facets by an independent radiologist.

The patients were monitored from 1 - 33 (mean 5.6) months after surgery, with complete elimination or a greater than 50% subjective reduction of pain considered the criteria for success. For the first or only procedure this was 41% overall, 37% in cases done under local anaesthesia, 46% in cases done under general anaesthesia (difference not statistically significant p=0.52). There was no statistically significant difference in success rates for procedures performed in the cervical, thoracic or lumbosacral facets, with unilateral versus bilateral denervations, when two to three as compared with more than three facets were denervated, nor for operations done in patients who had had previous spinal surgery compared with those who had not. Results were not better regardless of whether hyperextension of the spine aggravated the patient's preoperative pain or not, and when the procedures were repeated in the same patient outcomes tended to be consistent, arguing against repetition of failed facet denervations. The morbidity was low, the chief problem being sensory loss and transient neuropathic pain in the distribution of cutaneous branches of posterior rami in the cervical and thoracic areas; mortality was zero.

Percutaneous radiofrequency facet denervation is simple and safe, still worth considering in patients with disabling spinal pain that fails to respond to conservative treatment. The use of general anaesthesia shortens the operating time and the patient's discomfort without impairing success rate.

Postictal noserubbing (PIN) has been identified as a good, albeit imperfect, lateralizing and localizing sign in human partial epilepsy, possibly related to ictal autonomic activation.

PIN was studied prospectively in a group of consecutive patients admitted for video-EEG monitoring, with the laterality of noserubbing correlated with electrographic sites of seizure onset, intra- and interhemispheric spread, and sites of seizure termination.

PIN was significantly more frequent in temporal than extratemporal epilepsy (p<0.001; 23/41 (56%) patients and 41/197 (21%) seizures in temporal lobe epilepsy compared with 4/34 (12%) patients and 12/167 (7%) seizures in extratemporal epilepsy). The hand used to rub the nose was ipsilateral to the side of seizure onset in 83% of both temporal and extratemporal seizures. Seizures with contralateral PIN correlated with spread to the contralateral temporal lobe on scalp EEG (p<0.04). All extratemporal seizures with PIN showed spread to temporal lobe structures. One patient investigated with intracranial electrodes showed PIN only when ictal activity spread to involve the amygdala: seizures confined to the hippocampus were not associated with PIN. PIN was not observed in 63 nonepileptic events in 17 patients. Unexpectedly, one patient with primary generalized epilepsy showed typical PIN after 1/3 recorded absence seizures.

This study confirms PIN as a good indicator of ipsilateral temporal lobe seizure onset. Instances of false lateralization and localization appear to reflect seizure spread to contralateral or ipsilateral temporal lobe structures, respectively. Involvement of the amygdala appears to be of prime importance for induction of PIN.

To compare the clinical characteristics, natural history, and therapeutic outcome of patients with cervical dystonia (CD) with head tremor (HT+) and without head tremor (HT-).

We prospectively evaluated 114 consecutive patients of CD over a 9-month period with a detailed questionnaire. Chi-square and t-tests were employed for statistical analysis.

Seventy-eight (68.4%) patients had head tremor and 27 of them (34.6%) had tremor as one of the first symptoms. Age at onset of symptoms were similar in HT+ and HT- groups; however there was a higher prevalence in women in the former group (66.7% vs. 41.7%; p=0.01). HT+ patients had more frequent positive family history of essential-like hand/head tremor (21.8% vs. 5.5%; p<0.05), associated neck pain (92.3% vs. 77.8%; p<0.05), and essential-like hand tremor (40% vs. 8.3%; p<0.001). They also appeared to have more frequent history of preceding head/neck trauma (14.1% vs. 8.3%), frequent head rotation (88.5% vs. 69.4%) and antecollis (12.8% vs. 5.5%) but less often head tilt (37.2% vs. 47.2%) and gestes antagonistes (60.2% vs. 75%) than the HT- patients; however these differences were not statistically significant. The frequency of prior psychiatric illnesses, the incidence of dystonias in other parts of the body, frequency of retrocollis and shoulder elevation, and spontaneous remission were similar in the two groups.

Head tremor is common in CD and is more commonly associated with hand tremor and family history of tremor or other movement disorders. This supports a possible genetic association between CD and essential tremor (ET). Linkage studies are required to evaluate the genetic association between CD and ET.

The purpose of this study was to obtain information from Canadian neurosurgeons regarding their opinions on, and utilization of, intracranial pressure (ICP) monitoring for severe traumatic brain injury (TBI).

A brief survey was sent to practicing Canadian neurosurgeons questioning them about their utilization of, and confidence in, intracranial pressure monitoring in the management of patients with severe TBI.

One hundred and ninety-six surveys were mailed. There were 103 responses for a response rate of 52.6%. The vast majority of responding neurosurgeons (98.1%) utilized ICP monitoring in the management of patients with severe TBI, with most (63.4%) using it in more than 75% of their patients, 14.9% using it in 50-75% of patients, 14.9% in 25-50% of patients, and 6.9% using it in less than 25% of patients. The level of confidence that routine monitoring improves outcome from severe TBI ranged from 23.3% having a low level of confidence, 56.3% having an intermediate level of confidence, to 20.4% having a high level of confidence. Most respondents (78.6%) felt that some form of prospective trial evaluating the role of ICP monitoring in improving outcome from severe TBI was warranted; 17.4% felt such a trial was not warranted and 3.9% were uncertain.

While ICP monitoring has gained almost universal acceptance among responding Canadian neurosurgeons, their level of confidence that routine monitoring improves outcome from severe TBI was quite variable, with only 20.4% of respondents having a high level of confidence. Over 75% of respondents felt that some form of prospective trial evaluating the utility of ICP monitoring is warranted. This information is being used in consideration of a prospective trial addressing this issue.

The objective of this study was to evaluate the pattern of cognitive disturbances in Nigerian Africans with newly diagnosed epilepsy, prior to onset of drug therapy.

A total of 60 consecutive patients (mean age 31.6 ± 17.4, range 14 - 55 years) presenting with a clinical diagnosis of epilepsy were recruited for the study. Sixty healthy volunteers without a history of epilepsy and who were age-, sex- and level of education matched with the epileptic patients, were recruited as controls. The administration of cognitive tests was done with the FePsy computerized neuropsychological test battery. The tests administered were the visual and auditory reaction times, the continuous performance test and the recognition memory tests to assess mental speed, attention and memory respectively. The means of the cognitive performances of the epileptic patients and controls were statistically compared.

Epileptic patients performed worse than the controls across the spectrum of cognitive tasks assessed (P = 0.00001; P < 0.025), with the exception of the β parameter (response bias) of the vigilance test (P = 0.488; P> 0.025).

The cognitive impairments of short-term memory, psychomotor speed and sustained attention observed in this study are similar to those reported in the literature for patients with epilepsy. The results of this study will be useful in the counseling of patients on their educational, social and vocational needs.

Increases in hydroxyl radical production have been used as evidence of oxidative stress in cerebral ischemia/ reperfusion. Ischemia can also induce increased dopamine release from the striatum that may contribute to hydroxyl radical formation. We have compared hydroxyl radical production in the cortex and striatum as an index of oxidative stress in a rat model of focal cerebral ischemia with cortical infarction.

Using a three vessel occlusion model of focal cerebral ischemia combined with bilateral microdialysis, hydroxylation of 4-hydroxybenzoate (4HB) was continuously monitored in both hemispheres in either the lateral striatum or frontoparietal cortex. The ischemia protocol consisted of one hour equilibration, 30 min of three vessel occlusion, then release of the contralateral common carotid artery (CCA) for 2.5 h.

Induction of ischemia resulted in a 30-fold increase in dopamine release in the lateral striatum. Compared to the nonischemic striatum, the ratio of the hydroxylation product 3,4-dihydroxybenzoate (34DHB) to 4HB (trapping agent) in the ipsilateral striatum increased significantly 30 min after ischemia induction. In contrast, during the 30 min of three vessel occlusion there was no increase in the ratio in the cortex. Following the release of the contralateral CCA, the ratio from the ischemic cortex increased significantly compared to sham-operated animals. However, under all circumstances, the 34DHB/4HB ratio was greater in the striatum than in the cortex.

The increase in the 34DHB/4HB ratio in the lateral striatum coincides with the increased dopamine release suggesting a role for dopamine oxidation in the increased production of hydroxyl radicals. The significant increase in the ratio from the ischemic cortex compared to that from the sham-operated animals is consistent with increased oxidative stress induced by ischemia. However, the lower 34DHB/4HB ratio in the cortex whichdoes not receive dopaminergic innervation compared to the striatum suggests a different mechanism for hydroxyl radical production. Such an alternate mechanism may represent a more toxic oxidative insult that contributes to infarction.

Endovascular therapy is becoming an increasingly popular treatment for cerebral aneurysms. Total angiographic occlusion of small-necked aneurysms (<4 mm) can be obtained in a high percentage of cases. The endovascular treatment of wide-necked or fusiform aneurysms remains a challenge with complete angiographic occlusion reported in <15% of cases.

We describe the combined use of a flexible coronary stent and platinum coils to treat a wide-necked aneurysm of the distal left vertebral artery, in a patient with Grade IV subarachnoid hemorrhage.

The procedure was technically successful as the parent artery was protected by the stent while coils were deposited in the aneurysm lumen. Although angiographic aneurysm occlusion was incomplete, the dome was packed with coils. No further hemorrhage has occurred.

Combined endovascular stent and coil therapy is a promising technique for the treatment of wide-necked cerebral aneurysms.