Body impact or collision is the risk factor underlying all sports-related concussions. This study sought to determine whether collision rates in elite hockey differ between games played on North American size rinks as compared to games played on larger international size ice surfaces.

Videotapes of games from the 2001 and 2002 National Hockey League Stanley Cup finals, World Junior championships and the 2002 Winter Olympics were analyzed, with all collisions counted and separated into various categories (player/player bodycheck, player/player into boards, player/boards, player/ice, head/stick, head/puck). Further subdivisions included collisions involving the head directly or indirectly. Twenty-two games were analyzed, 11 played on the small ice and 11 on the big ice.

Significantly more collisions of all types (in all categories and subdivisions within categories) were found to occur on the smaller North American ice surface (P value differences from 0.01 to 0.00001).

The results of this study showed significantly fewer collisions of all types in elite hockey games played on the international size ice surface. The comparison groups studied here did differ in some aspects other than ice size and so replication of the findings with even more closely matched groups will be needed before definitive conclusions can be drawn. However, if these findings are replicable, it would suggest that a change to uniform usage of the larger international rinks, with no rule changes or other alterations in the game, could provide direct primary prevention to reduce the number of collisions, and, by extension, concussions, that occur in the sport.

Intravenous rt-PA (IV rt-PA) for acute stroke has raised many concerns, including its inadvertent use in patients presenting with acute stroke-like symptoms as the expression of their somatoform disorder. Diagnosis of the somatoform disorder is often delayed, and thrombolytics in these patients for their stroke-like presentation subjects them to risk for hemorrhage.

The presentation, neurological findings, and the therapeutic decision making was audited in 85 patients who received IV rt-PA for a diagnosis of acute stroke. All the surviving patients were re-examined neurologically at least three months after IV rt-PA. Baseline and follow-up brain CT scans were re-reviewed by a neuroradiologist who was blinded to clinical presentation and outcome. Patients whose clinical presentation, brain CT and neurological outcome did not fit into known or expected anatomical and clinical patterns of stroke underwent psychological assessment using the Minnesota Multiphasic Personality Inventory-2.

In two patients three stroke-like presentations of somatoform disorder inadvertently were treated with IV rt-PA. This was primarily caused by abbreviated neurological examination and narrow differential diagnosis.

Patients with somatoform disorder may present with symptoms mimicking acute stroke. Under the time constraints of IV rt-PA use, a diagnosis of somatoform disorder can be missed, subjecting such patients to the potential complications of thrombolytics.

The academic half-day (AHD) appears to have become widespread in Canadian neurology residency programs, but there is little published information about the structure, content, or impact of the AHD.

A written questionnaire was sent to the directors of all active Canadian adult and child neurology residency programs.

All 21 program directors responded. An AHD was operating in 15/15 adult and 5/6 child neurology programs. The AHD typically lasts three hours, and occurs weekly, 10 months per year. Most of the weekly sessions are lectures or seminars, usually led by clinicians, with about 90% resident attendance. Course-like features (required textbook, examinations) are present in many AHDs. There is a wide range of topics, from disease pathophysiology to practice management, with considerable variation between programs.

Almost all Canadian neurology programs now have an AHD. Academic half-days are broadly similar in content and format across the country, and residents now spend a substantial portion of their training attending the AHD. The impact of the AHD on how residency programs are organized, and on the learning, clinical work, and professional development of residents merits further study.

To conduct active surveillance of the Canadian paediatric population for children who have a progressive intellectual and neurological deterioration to detect the occurrence of cases of Creutzfeldt-Jakob disease or variant Creutzfeldt-Jakob disease.

Any child who is less than or equal to 18 years of age, who had a progressive loss of already attained intellectual/ developmental abilities and development of abnormal neurological signs of greater than three months duration was eligible for inclusion.

July 1999 to July 2001.

Enhanced active surveillance system for progressive intellectual and neurological deterioration was implemented to detect, prospectively, among the Canadian paediatric population. Each month, all paediatricians and paediatric neurologists in Canada were mailed a reporting form. All reported cases were reviewed by the principal investigator who classified the cases into one of four predetermined categories. Cases where there was evidence of neurological and intellectual regression without known cause were reviewed by a panel. Reported cases were reviewed for the possibility of classic or variant Creutzfeldt-Jakob disease.

Over 2200 physicians took part in this program. There was more than an 80% monthly return rate of the initial report form. Ninety-nine possible cases of progressive neurological and intellectual deterioration were reported. Sixty cases were classified as having a progressive neurological syndrome associated with intellectual deterioration. Fourteen cases were duplicates. One case of Creutzfeldt-Jacob disorder was found but no cases of the variant form of Creutzfeldt-Jacob disorder. Fifteen cases were felt not to meet the above-mentioned entry criteria.

To study the role of diabetes, gynecomastia and CAG triplet repeat size as disease modifying factors of neurologic expression in spinal bulbar muscular atrophy (SBMA, Kennedy's disease).

Twenty unrelated SBMApatients with confirmatory genetic testing were reviewed. Patterns of neurologic involvement were assessed (e.g. bulbar, asymmetric, proximal, distal, motor and sensory). Slopes of disease progression were calculated from serial quantified neurologic examinations. Patterns of neurologic involvement and course were correlated to the presence of diabetes, gynecomastia and triplet repeat size.

Diabetes or glucose impairment occurred in nine and 11 had gynecomastia. Patterns of neurologic involvement and rates of progression did not correlate with these endocrine diseases or triplet repeat sizes. Correlation was seen between number of CAG repeats and age of onset weakness (r = -0.53, r2 = 29%, p = 0.01).

The specific neurotoxic effect of expanded CAGs appears limited to age of onset weakness in SBMA. Although significant, only 29% of the variability in onset age could be accounted for by polyglutamine size suggesting the importance of other unidentified factors. In this series diabetes or glucose impairment was more common than previously reported and, like gynecomastia, did not correlate with size of triplet repeats, severity or patterns of neurologic involvement. Modifying factors other than diabetes, gynecomastia or triplet repeat size are suggested in disease expression.

Fewer than 30 cases of oligodendroglioma or anaplastic oligodendroglioma metastatic to bone are reported in the literature. Prolonged survival even with therapy is uncommon.

We report a case of anaplastic oligodendroglioma metastatic to bone with a dramatic and durable response to temozolomide therapy. A retrospective case review, molecular analysis, and literature search were performed.

The patient presented with a right frontal mass in 1990. Progression led to resection of the lesion in 1995. Histology revealed an anaplastic oligodendroglioma and the tumour was found to have allelic loss of heterozygosity (LOH) of chromosome 1p (1p-). He received standard radiation therapy. In 2000 he developed hip and pelvic pain. A bone scan showed multiple skeletal lesions. Magnetic resonance imaging of the brain showed stability of intracranial disease. Resection of one lesion found metastatic anaplastic oligodendroglioma with identical morphology to the patient’s original tumour, including glial fibrillary acidic protein expression. The patient was started on standard temozolomide chemotherapy and celecoxib with prompt pain relief, and rapid normalization of serum alkaline phosphatase. He received a total of 12 cycles of combined therapy with no toxicity and no evidence of progression until increasing pain marked disease recurrence. The patient underwent palliative chemo- and radiation therapy but eventually succumbed.

Loss of heterozygosity 1p- is associated with prolonged survival in anaplastic oligodendroglioma and may increase the cumulative risk for development of systemic metastases. We speculate that metastases from oligodendroglioma harbouring loss of heterozygosity at chromosome 1p- retain the chemosensitivity of the initial lesion.

The pathophysiological basis for differences in disability in patients with multiple sclerosis is unclear.

We used magnetic resonance imaging to examine whether differences in disability in cohorts of multiple sclerosis patients with similar T2-weighted lesion volume and disease duration were associated with a more destructive disease process in the more disabled patients.

The benign and severely disabled groups had similar brain atrophy metrics and similar decreases of the neuronal marker, N-acetylaspartate, in the normal appearing white matter of the cerebrum on magnetic resonance spectroscopy examination in vivo. The severely disabled cohort had more spinal cord atrophy.

The dissociation of spinal cord atrophy and cerebral atrophy between these two groups suggests that the difference between the more benign and more disabled groups cannot be explained by a more aggressive pathological process that is affecting the entire neuroaxis in a homogeneous fashion.

Nestin is a class VI intermediate filament protein, expressed during early embryonic development in mammals. Postnatally, nestin and its mRNA are down-regulated and gradually disappear. Recently, nestin expression has been detected in the adult nervous system, and it has been suggested that this protein may be related to neurogenesis, although, its role in the mechanism of neurogenesis is not known.

The present study examined the localization of nestin in CNS tissue of the amygdaloid kindled rat by light and electron microscopy.

Kindled animals showed nestin expression mainly in the piriform cortex and the perirhinal cortex. By light microscopy, nestin was shown to be expressed in astrocytes, neurons, and endothelial cells. Electron microscopy demonstrated nestin expression in endothelial cells, astrocytic perivascular end feet, the rare pericyte, neurons and oligodendrocytes.

We conclude that epilepsy causes widespread nestin expression in many cell types in the CNS, including non-neural cells.

Predicting the ability of drugs to enter the brain is a longstanding problem in neuropharmacology. The first step in creating a much-needed computational algorithm for predicting whether a drug will enter brain is to devise a rigorous mathematical model.

Employing two experimental measures of blood-brain barrier (BBB) penetrability (brain/plasma ratio and the brain-uptake index) and 14 theoretically derived biophysical predictors, a mathematical model was developed to quantitatively correlate molecular structure with ability to traverse the BBB.

This mathematical model employs Stein's hydrogen bonding number and Randic's topological descriptors to correlate structure with ability to cross the BBB. The final model accurately predicts the ability of test molecules to cross the BBB.

A mathematical method to predict blood-brain barrier penetrability of drug molecules has been successfully devised. As a result of bioinformatics, chemoinformatics and other informatics-based technologies, the number of small molecules being developed as potential therapeutics is increasing exponentially. A biophysically rigorous method to predict BBB penetrability will be a much-needed tool for the evaluation of these molecules.

Friedrich ataxia (FRDA1) is most often the result of a homozygous GAA repeat expansion in the first intron of the frataxin gene (FRDA gene). This condition is seen in individuals of European, North African, Middle Eastern and Indian descent and has not been reported in Southeast Asian populations. Approximately 4% of FRDA1 patients are compound heterozygotes. These patients have a GAA expansion on one allele and a point mutation on the other and have been reported to have an atypical phenotype.

To describe a novel dinucleotide deletion in the FRDA gene in two Malaysian siblings with FRDA1.

Tertiary referral university hospital setting. Patients and

A previously healthy 10-year-old Malaysian boy, presented with fever, lethargy, headaches, dysarthria, dysphagia, vertigo and ataxia which developed over a one week period. His neurological exam revealed evidence of dysarthria and ataxia, mild generalized weakness and choreoform movements of the tongue and hands. His reflexes were absent and Babinski sign was present bilaterally. A nine-year-old sister was found to have mild ataxia but was otherwise neurologically intact.

Molecular genetic studies demonstrated that both siblings were compound heterozygotes with a GAA expansion on one allele and a novel dinucleotide deletion on the other allele.

We describe a novel dinucleotide deletion in the first exon of the FRDA gene in two siblings with FRDA1. Additionally this is the first report of FRDA1 occurring in a family of southeast Asian descent, it demonstrates intrafamilial phenotypic variability, and confirms that atypical phenotypes are associated with compound heterozygosity.

Long latency reflexes (LLR) include afferent sensory, efferent motor and central transcortical pathways. It is supposed that the cortical relay time (CRT) reflects the conduction of central transcortical loop of LLR. Recently, evidence related to the cortical involvement in multiple sclerosis (MS) has been reported in some studies. Our aim was to investigate the CRT alterations in patients with MS.

Upper extremity motor evoked potentials (MEP), somatosensory evoked potentials (SEP) and LLR were tested in 28 patients with MS and control subjects (n=22). The patients with MS were classified according to the clinical form (relapsing-remitting [R-R] and progressive groups). The MS patients with secondary progressive and primary progressive forms were considered as the “progressive” group. CRT for LLR was calculated by subtracting the peak latency of somatosensory evoked potentials (SEP) and that of motor evoked potentials (MEP) by transcranial magnetic stimulation from the onset latency of the second component of LLR (LLR2) (CRT = LLR2 – [MEP latency + N20 latency])

Cortical relay time was calculated as 7.4 ± 0.9 ms in control subjects. Cortical relay time was prolonged in patients with MS (11.2 ± 2.9 ms) (p<0.0001). The latencies of LLR, MEP and SEP were also prolonged in patients with MS. Cortical relay time was not correlated with disease severity and clinical form in contrast to other tests.

Our findings suggested that CRT can be a valuable electrophysiological tool in patients with MS. Involvement of extracortical neural circuits between sensory and motor cortices or cortical involvement due to MS may cause these findings.

Methylphenidate is a central nervous system stimulant used for the treatment of attention deficit hyperactivity disorder and narcolepsy and like other psychostimulants has a potential for abuse.

A young man with a cerebral lacunar infarction following chronic oral abuse of methylphenidate is presented.

The experience of our patient and a review of the literature suggest that cerebral infarction is a potential side effect of chronic consumption of methylphenidate.

The nervous system is a major target of HIV-1 infection and site of many complications of AIDS. Most of our knowledge pertaining to the range and frequency of neuropathology in HIV-1/AIDS is from large centres outside Canada in different social and health care settings. The goal of the present study was to describe HIV-1/AIDS-associated neuropathology before and during the era of highly active antiretroviral therapy at a Canadian teaching centre.

The records of the Department of Pathology, London Health Sciences Centre were electronically searched for cases of HIV-1/AIDS that came to postmortem examination since 1985. The clinical records and pathological materials were reviewed.

Sixteen autopsies of HIV-1/AIDS were identified. All patients were male. Fourteen contracted HIV-1 through high risk homosexual activity, one through the transfusion of blood products and one through intravenous drug use. Three patients (19%) had pre-mortem evidence of HIV-1 associated dementia. At autopsy, 12 of the 16 cases had neuropathological findings and the most common diagnoses were HIV-1 encephalitis, progressive multifocal leukoencephalopathy, toxoplasmosis, and primary CNS lymphoma.

High risk homosexual activity was a more prominent factor in acquiring AIDS in cases coming to postmortem examination compared with previous reports from most larger urban centres outside Canada where injection drug use and high risk heterosexual activity factored prominently. The incidence of HIV-1 associated dementia was similar to that reported previously. This study confirms the heavy burden and wide spectrum of disease experienced by the nervous system in HIV-1/AIDS.

Fabry’s disease is an X-linked disorder, caused by a deficiency of the lysosomal enzyme α-galactosidase A which results in the accumulation of the glycosphingolipid, ceramide trihexose in the vascular endothelium and can lead to cerebral infarction. Male hemizygotes are generally more severely affected than heterozygote females. Clinical disease in females is thought to be due to unequal X chromosome inactivation.

A 19-year-old woman, who was previously well, presented with neurological deficits secondary to basal ganglia and pontine infarction. Extensive cardiac, arterial and hematologic investigations did not identify the etiology of her stroke. Muscle biopsy revealed endothelial lysosomal aggregates most consistent with a diagnosis of Fabry’s disease. The diagnosis was confirmed on the basis of molecular genotype analysis.

Inherited causes of stroke such as Fabry’s disease should be considered in young patients with stroke if an etiologic diagnosis is not reached after complete investigations. Muscle biopsy can assist with the diagnosis and guide further investigations. This report summarizes the biochemical and histological features of Fabry’s disease and the associated genetic abnormalities.

Stroke incidence has fallen since 1950. Recent trends suggest that stroke incidence may be stabilizing or increasing. We investigated time trends in stroke occurrence and in-hospital morbidity and mortality in the Calgary Health Region.

All patients admitted to hospitals in the Calgary Health Region between 1994 and 2002 with a primary discharge diagnosis code (ICD-9 or ICD-10) of stroke were included. In-hospital strokes were also included. Stroke type, date of admission, age, gender, discharge disposition (died, discharged) and in-hospital complications (pneumonia, pulmonary embolism, deep venous thrombosis) were recorded. Poisson and simple linear regression was used to model time trends of occurrence by stroke type and age-group and to extrapolate future time trends.

From 1994 to 2002, 11642 stroke events were observed. Of these, 9879 patients (84.8%) were discharged from hospital, 1763 (15.1%) died in hospital, and 591 (5.1%) developed in-hospital complications from pneumonia, pulmonary embolism or deep venous thrombosis. Both in-hospital mortality and complication rates were highest for hemorrhages. Over the period of study, the rate of stroke admission has remained stable. However, total numbers of stroke admission to hospital have faced a significant increase (p=0.012) due to the combination of increases in intracerebral hemorrhage (p=0.021) and ischemic stroke admissions (p=0.011). Sub-arachnoid hemorrhage rates have declined. In-hospital stroke mortality has experienced an overall decline due to a decrease in deaths from ischemic stroke, intracerebral hemorrhage and sub-arachnoid hemorrhage.

Although age-adjusted stroke occurrence rates were stable from 1994 to 2002, this is associated with both a sharp increase in the absolute number of stroke admissions and decline in proportional in-hospital mortality. Further research is needed into changes in stroke severity over time to understand the causes of declining in-hospital stroke mortality rates.

Periventricular white matter disease (PVWD) is associated with abnormalities on tests that involve complex cognitive processes, along with an increased risk of cerebrovascular events which are associated with significant morbidity in older patients. This study investigates whether the neurological examination can predict the presence of PVWD on magnetic resonance imaging (MRI). No prior studies have assessed whether the neurological examination can predict the presence of PVWD on MRI.

A focused neurological examination was performed on a random selection of patients referred for a MRI of the brain. Staff neuroradiologists who were blinded to the results of the physical examination independently read the MRI scans. The MRI interpretations were divided into four categories based on the degree of PVWD: none, mild, moderate, severe.

Twenty-three subjects had some degree of PVWD, while 25 subjects had none. The total number of neurologic signs correlated significantly with the severity of PVWD even when adjusting for the effect of age (rho=0.67, p<0.001). Ninety-one percent of subjects with PVWD had three or more abnormal signs, while 76% of subjects without PVWD had fewer than three. Abnormalities with the three step motor sequencing and horizontal visual tracking tests were maximally predictive of PVWD. One or both of these tests were abnormal in 96% of subjects with PVWD, while 64% of subjects without PVWD had no problems with either test.

Simple neurologic tests can predict the presence or absence of PVWD on MRI.

Metastatic renal cell carcinoma to the choroid plexus is a rare condition and can be easily confused with meningioma.

A 61-year-old female presented with progressive neurologic deterioration and MRI findings of obstructive hydrocephalus and a homogeneously contrast enhancing 3 cm oval mass in the trigone of the left lateral ventricle.

Despite radiologic, intraoperative gross features, and frozen pathology all consistent with meningioma, the final pathology revealed metastatic renal cell carcinoma.

Renal cell carcinoma metastatic to the choroid plexus can mimic intraventricular meningioma. We present a review of the literature and comparison of the radiological features of meningiomas and metastatic renal cell carcinoma. We also discuss the use of an under-utilized technique, the contralateral transcallosal approach, in the surgical treatment of this intraventricular lesion.

The effect of liver transplantation on pre-existing multiple sclerosis (MS) has never been reported. We report the three year post-transplant neurological outcome of a patient with MS.

A Caucasian woman with MS received an urgent liver transplant for fulminant liver failure at the age of 59. Her Extended Disability Scale Score (EDSS) pretransplant was 5.0 and clinically she had cerebellar and brainstem dysfunction. Post-transplant immunosuppression consisted of tacrolimus, mycophenolate mofetil and tapering corticosteroids that were discontinued after 1.5 years. Post-transplant her EDSS decreased to 2.0 and after three years she is clinically asymptomatic with only very mild dysarthria on neurologic examination. Long-term maintenance immunosuppression consists of low dose tacrolimus.

Combination immunosuppression with tacrolimus may have a beneficial effect on MS although an effect of donor allograft itself can not be excluded.

While the risk of developing seizures following a mild head injury has been reported and is thought to be low, the effect of mild head injury on patients with a pre-existing seizure disorder has not been reported. We present a series of cases where a strong temporal relationship between mild head injury and worsening of seizure frequency was observed.

Five cases were identified and reviewed in detail. Information was derived from clinic and hospital charts with attention to the degree of injury, pre- and postinjury seizure patterns and frequency.

One patient has primary generalized epilepsy and four have localization related epilepsy. Prior to the head injury, three of the patients were seizure free (range: two to 24 years). The patients suffered from mild head injuries with no or transient loss of consciousness and no focal neurological deficits. In all cases, the patients experienced a worsening of seizure control within days of the injury. In one case, the patient's seizure pattern returned to baseline one year after the accident, while in the remaining four cases, the patients continue to have medically refractory seizures.

A close temporal relationship between mild head injury and a worsening of seizure control was observed in five patients with epilepsy. Although further study is required, this observation suggests that a head injury that would be considered benign in the general population can have serious consequences such as recurrence of seizures and medical intractability in patients with epilepsy.