It is often difficult to differentiate a recurrent glioma from the effects of post-operative radiotherapy by means of conventional neurodiagnostic imaging. Proton magnetic resonance spectroscopic imaging (1H-MRSI), that allows in vivo measurements of the concentration of brain metabolites such as choline-containing phospholipids (Cho), may provide in vivo biochemical information helpful in distinguishing areas of tumor recurrence from areas of radiation effect.

Two patients who had undergone resection and post-operative radiotherapy for a cerebral glioma became newly symptomatic. Computed tomographic (CT) and magnetic resonance imaging (MRI) performed after the intravenous infusion of contrast material, and in one case, [18F] fluorodeoxyglucose positron emission tomography (PET), could not differentiate between the possibilities of recurrent glioma and radiation effect. The patients underwent 1H-MRSI prior to reoperation and the 1H-MRSI results were compared to histological findings originating from the same locations.

A high Cho signal measured by 1H-MRSI was seen in areas of histologicallyproven dense tumor recurrence, while low Cho signal was present where radiation changes predominated.

The differentiation between the recurrence of a cerebral glioma and the effects of post-operative irradiation was achieved using 1H-MRSI in these two patients whose conventional neurodiagnostic imaging was equivocal for such a distinction. Where these two conditions are present, metabolite images from 1H-MRSI, such as that based on Cho, can be co-registered with other imaging modalities such as MRI and may also be integrated with functional MRI or functional PET within a multimodal imaging-guided surgical navigation system to assure maximal resection of recurrent tumor while minimizing the risk of added neurological damage.

Multiple sclerosis (MS) is a common neurologic disease in young and middle-aged adults affecting approximately 35,000 Canadians. The objectives of this study were to estimate the annual and lifetime costs of MS from the Canadian societal perspective.

Patients were consecutively recruited by neurologists in 14 MS outpatient clinics across Canada. They were classified according to the Expanded Disability Status Scale (EDSS) into three groups: mild (EDSS ≤ 2.5), moderate (EDSS = 3.0-6.0) and severe (EDSS ≥ 6.5). Sociodemographic, clinical and resource utilization data were collected retrospectively for the three months prior to patient inclusion. Costing of resources was performed from Ministry of Health, private third party payers, patient and societal perspectives. Average Canadian costs ($CDN 1995) were valued from available provincial data.

A total of 198 patients were included in the analysis (mild: n = 62, moderate: n = 68 and severe: n = 68). Costs increased with increasing EDSS scores, from all perspectives. The annualized societal costs per patient were $CDN 14,523, $CDN21,698 and $CDN37,024 for the mild, moderate and severe groups, respectively. In all severity groups, most of the financial burden is borne by patients, from 74% to 88%. Indirect costs, namely lost daily activity/leisure time and lost productivity, were the major societal cost drivers. The lifetime cost of MS, including patient institutionalization, was estimated to be $CDN 1,608,000 per patient.

In Canada, MS is associated with enormous direct and indirect costs. Patients carry most of the economic burden of this disease. The results of this burden of illness study provide a basis for cost-effectiveness analyses of new therapeutic interventions for MS.

In the absence of a biological marker for Alzheimer's disease (AD), diagnosis has to be achieved using clinical criteria sets such as those outlined in DSM-IV, NINCDS-ADRDA, or ICD-10. As these criteria are quite broadly defined, there may be inter-rater variability in interpretation.

Using a previously published CT scan measuring technique which correlates well with diagnoses achieved using the NINCDS-ADRDA criteria as interpreted at our clinic, we chose to independently examine and reach a diagnosis in patients selected for participation in clinical trials of therapeutic agents for the treatment of AD. Forty-four CT scans from six investigators across Canada were examined using this model. All patients had been diagnosed as having AD by NINCDS-ADRDA criteria and were deemed acceptable to participate in a clinical trial.

The diagnostic concordance achieved in the original published model was 91.5%. The diagnostic concordance in the population currently being studied was 77.3%. However when examined by site, results ranged from 57.1% to 100%. Using the model, an index of atrophy and a probability of diagnosis of AD can be determined. Across sites, there were statistically significant differences in these measures (p ≤ 0.035). The mean probability of diagnosis of AD across sites ranged from 0.56 to 0.94. Although the sites with lower probabilities had slightly lower mean ages and slightly less atrophy, there was no overall correlation of the atrophy measures with age.

Current results raise the possibility that the selection of patients for AD clinical trials using current diagnostic criteria sets may not be adequate and conclusions with respect to agent efficacy could be flawed.

As many as 20% of individuals with the clinical diagnosis of Parkinson's disease (PD) do not have the characteristic neuropathologic features of PD at post mortem. The striatonigral degeneration (SND) subtype of multiple system atrophy is one of the categories of pathology which may be incorrectly diagnosed as PD on the basis of clinical presentation. SND may be associated with increased iron deposition in the putamen which can be detected with magnetic resonance imaging.

We have estimated regional brain iron content in a patient with probable SND, using a novel imaging method developed in our laboratory, and have compared the results in this patient to those which we have previously reported in patients with PD and in age-matched controls.

We observed that putamenal iron content was increased in our SND patient, beyond the 95% confidence limit for inclusion in the PD group, even when considering clinical severity. In contrast, pallidal and thalamic iron were within the PD range.

The demonstration of increased putamenal iron content may be a useful adjunctive investigative procedure in patients with suspected SND.

Tropical Spastic Paraparesis/HTLV-I Associated Myelopathy (HAM/TSP) is a chronic, progressive myelopathy endemic to the Caribbean. In HAM/TSP, peripheral motor pathways have been assessed using electromyography and nerve conduction studies; central motor pathways have been assessed to a limited extent using electrocortical stimulation. We used magnetic cortical stimulation (a painless alternative to electrocortical stimulation) and F-wave analysis to study conduction in the central and peripheral motor pathways in 18 HTLV-I seropositive, Jamaican TSP patients (ages 29- 70 years; duration of symptoms 3-20 years) and 22 normal controls.

Magnetic cortical stimulation was effected using a 9 cm diameter undamped MES10 coil. F-waves and M-responses were elicited by electrical stimulation of the ulnar nerve at the wrist, and deep peroneal stimulation at the knee. Stimulation and recording of response latencies in abductor digitii minimi (ADM) and tibialis anterior (TA) were carried out using a Cadwell Excel system.

With cortical stimulation, response latencies (TMCTs) to ADM and TA were prolonged in the patients relative to controls. F-wave and M-response latencies were unaffected, suggesting no peripheral pathology. Latency (CMCT) between cortex and lumbar cord was significantly prolonged; that between cortex and C7/T1, also, but less markedly (P < 0.0005). Amplitudes of cortically evoked responses were significantly reduced only in the lower limbs (TA). CMCT increased as the disease progressed from mild to moderate, thereafter remaining largely unchanged.

Meta-analysis of interlaboratory control data revealed no significant differences in TMCTs between our controls and others studied using similar techniques. The observations are consistent with pathology affecting mainly the thoracolumbar cord in HAM/TSP.

Adenosine is a powerful natural vasodilator that participates in the control of cerebral and meningeal blood flow. In this context, it could be involved in the pathophysiology of migraine, since it was previously reported that intravenous adenosine can precipitate crises in migraine patients.

We have investigated circulating adenosine levels in 12 patients suffering from migraine without aura, during crises and in crisis-free periods, and have compared the levels noted to those of a population of 10 controls. To determine if there are interactions between adenosine and serotonin, we examined the effect of adenosine and antagonists on the uptake and the release of (14C) serotonin by platelets.

We have reached a dual conclusion: 1) during migraine headaches there is an increase (mean 68%) in circulating adenosine levels and this increase may participate in cephalalgia; 2) activation of A2 receptors by adenosine causes a dose-dependent inhibition of calcium-dependent serotonin uptake by platelets. This inhibition of uptake could participate in the rapid elimination of serotonin in migraine sufferers. As a result of this, the use of adenosine antagonists could be an effective complementary treatment for migraine.

Machado-Joseph disease (MJD) is a dominantly inherited cerebellar ataxia associated with spasticity, ophthalmoplegia and dystonia. There has been no report of electrophysiological or histological alterations of the peripheral nervous system in patients with MJD.

Four patients with MJD were identified by polymerase chain reaction. The peripheral nerves of these patients were subjected to electrophysiological testing and histological study. Correlation analyses were made between various clinical parameters and the electrophysiological and histological changes.

Electrophysiological studies demonstrated a marked reduction of sensory action potential, acute denervation changes on needle EMG, as well as mild decrease in the compound motor action potential. Light microscopy of the sural nerves revealed clear loss of myelinated fibers, and morphometry studies showed a loss of large myelinated fibers. Moreover, the severity of these pathological changes was found to be related to the CAG repeat length in the MJD gene.

Our findings indicated that the peripheral nervous system was frequently affected in patients with MJD. These findings were similar to those seen in Friedreich's ataxia, suggesting a loss of sensory and motor fibers probably following a lesion of the dorsal root ganglion and the anterior horns in the spinal cord. Furthermore, the number of CAG repeats seems to have an inverse relationship to the extent of pathological changes of the peripheral nerves.

Antibodies to cardiolipin and other phospholipids have been associated with recurrent thrombotic events, including stroke.

Over a 16 month period we assessed an unselected cohort of 151 ischemic stroke patients for the presence of antiphospholipid antibodies. Patients with known systemic lupus erythematosis, systemic sclerosis, or Sjogrens Syndrome were excluded. Sera from patients admitted to hospital with a diagnosis of ischemic stroke (n = 151) and from controls (n = 111) assessed during the same period were tested for antiphospholipid antibodies (APLA) using 3 assays; anticardiolipin antibodies (ACA) by ELISA, prolonged activated partial thromboplastin time (APTT), and VDRL.

The average age of ischemic stroke cases was 68 years (range 29 to 91) and of controls 63 years (range 29 to 86). The prevalence of APLA detected by at least one of the three methods was 12% for IS cases and 10% for controls. After correcting for known risk factors such as age, gender, diabetes mellitus, heart disease, hypertension, and smoking, the odds ratio for risk of stroke fell to 0.8 (C.I. 0.4 to 1.2).

Our findings suggest that APLA may not be an independent risk factor for ischemic stroke in unselected persons who do not have known systemic lupus erythematosis or systemic sclerosis but further evaluation of the role of lupus anticoagulant is indicated.

The present study was designed to find the differences in regional cerebral blood flow and cerebrovascular acetazolamide reactivity between leuko-araiosis with and without lacunar infarction.

Fifteen cases of leuko-araiosis with lacunar infarction, 15 cases of leuko-araiosis without lacunar infarction and 15 age-matched controls in which leuko-araiosis and cerebrovascular diseases are absent (control group) were studied. The regional cerebral blood flow was measured using the stable xenon computed tomography method before and 20 minutes after intravenous injection of 17 mg/kg acetazolamide.

The blood flows in the leuko-araiosis area and the lacunar area were significantly lower than the blood flow in the cerebral white matter. The blood flows in the cerebral cortex and the cerebral white matter were significantly lower in the leuko-araiosis with lacunar infarction group than in the leuko-araiosis without lacunar infarction group and the control group. The cerebrovascular acetazolamide reactivity in the leuko-araiosis area and the lacunar area was significantly lower than that in the cerebral white matter. The cerebrovascular acetazolamide reactivity in the cerebral cortex and the cerebral white matter was significantly lower in the leuko-araiosis with lacunar infarction group than in the leuko-araiosis without lacunar infarction group and the control group.

The degree of arteriolosclerosis is considered to be more severe and the rate of association of hypertension was higher in leuko-araiosis with lacunar infarction than in leuko-araiosis without lacunar infarction.

Cerebrovascular complications of meningitis have been most extensively documented in the setting of acute bacterial or chronic tuberculous meningitis. Involvement of major cerebral vessels is rare and basilar artery thrombosis has not been reported in fungal meningitis secondary to Candida infection.

We describe the clinical course and neuropathological findings in a woman with chronic meningitis due to Candida albicans.

The diagnosis remained elusive antemortem despite analysis of 7 large volume CSF samples and examination of a meningeal and cortical biopsy. Death followed extensive brainstem and temporo-occipital infarction secondary to basilar artery thrombosis. The basilar artery occlusion was secondary to an intense, granulomatous and necrotizing basal meningitis focally extending to the media and intima.

This paroxysmal and devastating complication of untreated chronic candida meningitis reinforces that a trial of empirical therapy with both antituberculous and antifungal agents should be considered in most cases of chronic culture-negative lymphocytic meningitis.

Tension pneumocephalus, the accumulation of intracranial gas under pressure, is a rare but potentially life-threatening condition which can complicate craniofacial surgery, trauma, or cranial tumor. It presents as an acute or subacute expanding mass lesion.

We present a case of a 40-year-old male who developed tension pneumocephalus as a consequence of a previously detected but untreated frontal sinus osteoma. Despite prompt decompression and repair of the fistulous connection between the sinus and the intracranial compartment, the patient suffered permanent frontal lobe damage with significant neurocognitive sequelae and seizures.

This case illustrates that tension pneumocephalus can be a dangerous entity with potential for early mortality and long-term morbidity. We recommend, therefore, early treatment and close follow up of destructive lesions involving the posterior frontal sinus wall.

The central nervous system is often involved in Behcet's disease. Most common are meningoencephalitic and brain stem syndromes. Although basal ganglia involvement is not an uncommon finding on necropsy, there are only single reports on extrapyramidal syndromes-dyskinesia, chorea and Parkinsonism in patients with Behcet's disease.

We report a patient fulfilling the criteria of the International Study Group for Behcet's disease. He had recurrent oral ulcerations, bilateral posterior uveitis and retinal vasculitis, skin papules and pustules, and recurrent monoarthritis. Neurologic examination revealed pseudobulbar palsy, slight and asymmetric bilateral pyramidal syndrome, muscle rigidity involving the four limbs, bradykinesia, masked face, and impaired postural reflexes. There was postural tremor in the extremities and myoclonic jerks involving the tongue and face muscles. Magnetic resonance imaging demonstrated small bilateral multifocal hyperintense lesions, with right predilection, involving the periventricular white matter, brain stem and basal ganglia.

The Parkinsonian syndrome found in our patient might be due to involvement of both substantia nigra and basal ganglia. This case further emphasizes the wide spectrum of the neurological manifestations of Behcet's disease