Clinical safety of intracranial EEG electrodes in MRI at 1.5 T and 3 T: a single-center experience and literature review.

PURPOSE: Intracranial electroencephalography (EEG) can be a critical part of presurgical evaluation for drug resistant epilepsy. With the increasing use of intracranial EEG, the safety of these electrodes in the magnetic resonance imaging (MRI) environment remains a concern, particularly at higher field strengths. However, no studies have reported the MRI safety experience of intracranial electrodes at 3 T. We report an MRI safety review of patients with intracranial electrodes at 1.5 and 3 T. METHODS: One hundred and sixty-five consecutive admissions for intracranial EEG monitoring were reviewed. A total of 184 MRI scans were performed on 135 patients over 140 admissions. These included 118 structural MRI studies at 1.5 T and 66 functional MRI studies at 3 T. The magnetic resonance (MR) protocols avoided the use of high specific energy absorption rate sequences that could result in electrode heating. The intracranial implantations included 114 depth, 15 subdural, and 11 combined subdural and depth electrodes. Medical records were reviewed for patient-reported complications and radiologic complications related to these studies. Pre-implantation, post-implantation, and post-explantation imaging studies were reviewed for potential complications. RESULTS: No adverse events or complications were seen during or after MRI scanning at 1.5 or 3 T apart from those attributed to electrode implantation. There was also no clinical or imaging evidence of worsening of pre-existing implantation-related complications after MR imaging. CONCLUSION: No clinical or radiographic complications are seen when performing MRI scans at 1.5 or 3 T on patients with implanted intracranial EEG electrodes while avoiding high specific energy absorption rate sequences.

Establishing a Canadian registry of patients with amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating cause of progressive weakness, respiratory failure and death. To date there is no effective therapy to meaningfully extend survival but continuously emerging targets and putative treatments are studied in clinical trials. Canadian epidemiological data on ALS is scarce and the socioeconomic impact of ALS on Canadian society is unclear. The Canadian Neuromuscular Disease Registry (CNDR) is a national clinic-based registry of patients with neuromuscular diseases with the goal of facilitating the design and execution of clinical research. METHODS: We conducted a national stakeholder survey to assess interest for a Canadian ALS registry and an assessment of expected case ascertainment. A dataset derivation meeting was held to establish the registry medical dataset. RESULTS: We report the results of the national stakeholder survey, case ascertainment assessment, and the derived dataset that have resulted in the current implementation of a Canadian registry of patients with ALS. CONCLUSIONS: The development of this long sought-after resource is a significant step forward for the Canadian ALS patient and research communities that will result in more efficient clinical trial recruitment and advancements in our understanding of ALS in Canada.

Adult-onset epilepsy associated with dysembryoplastic neuroepithelial tumors.

RATIONALE: Dysembryoplastic neuroepithelial tumors (DNET) are benign, localized lesions that typically cause localization-related epilepsy of childhood onset. Although excellent seizure outcomes are expected following surgical resection of focal, benign lesions, reports in pediatric epilepsy series suggest that this may not be the case with DNETs, which may exhibit complex and often multifocal epileptogenesis. We report the characteristics and surgical outcome of an adult- and childhood-onset cohort with this condition. METHODS: Retrospective cohort of 23 patients seen at two major epilepsy centers, with localization-related epilepsy associated with histopathologically demonstrated DNETs. We assessed clinical, electrographic and surgical outcome features in patients with adult- and childhood-onset epilepsy. We were particularly interested in the level of congruence of EEG and MRI data and the need for intracranial recordings. We evaluated seizure outcomes at last follow-up. RESULTS: The mean age was 33.3 years (range: 5-56 years). Ten patients had adult-onset epilepsy. Thirteen patients (57%) had simple partial, 21 (91%) had complex partial, 16 (70%) had secondarily generalized seizures and 5 patients had only simple partial seizures. Status epilepticus did not occur. Non-enhancing lesions on MRI were located in the temporal lobe in 17 patients, the frontal lobe in 3 patients and the parietal/occipital region in 2 patients. One patient had a DNET that involved both frontal and temporal areas. Ictal scalp EEG and MRI were congruent in 17 patients (74%). Eleven patients (48%) underwent lesionectomies, while the rest required some resection of extralesional cortex as well. Five patients required intracranial EEG. There was no association with cortical dysplasia. Seventeen patients (74%) had an Engel class 1 outcome, in a follow-up period that ranging from 5 to 98 months. CONCLUSIONS: We found no difference in outcomes between adult- and childhood-onset cases. Although epileptogenicity was complex, congruence between electro-clinical and neuroimaging studies was high and allowed good surgical outcomes at 1 year of follow-up.

Deterioration in the health-related quality of life of persons with multiple sclerosis: the possible warning signs.

Baseline data from a population-based study examining the health-related quality of life (HRQL) of MS patients about to begin disease modifying therapy was used to determine the factors associated with the HRQL of Saskatchewan adults with relapsing-remitting MS. Participants completed a self-report questionnaire regarding demographic and socioeconomic status, fatigue, comorbid medical conditions, disability level (EDSS), number of attacks in past 6 months, illness intrusiveness (Illness Intrusiveness Ratings Scale), depression (Beck Depression Inventory), and HRQL (SF-36 Health Status Survey). Multiple linear regression models were used to identify the factors associated with the physical and mental health summary scores of the SF-36. We found poorer physical HRQL in those who are female; older; not working; have musculoskeletal or respiratory problems; greater fatigue, higher disability scores, and more MS attacks. High illness intrusiveness; digestive system problems; genitourinary problems; and headaches were associated with poorer mental HRQL. Interestingly, we found an interaction between sex and age in mental HRQL, with worse mental health in older men but better mental health in older women. These findings may assist health care providers in identifying patients who may be at risk for decline in their HRQL, permitting appropriate and timely interventions.

Therapeutic action of cannabinoid on axonal injury induced by peroxynitrite.

This study examined whether the potent cannabinoid HU210 ameliorates axonal injury through its indirect action to stimulate the secretion of corticosterone. We observed that HU210 dramatically reduced peroxynitrite-induced axonal injury in rats receiving adrenalectomy and corticosterone replacement treatment. These results suggest that the ameliorating effects of cannabinoids on axonal injury associated with multiple sclerosis are achieved by its direct action, but not by its indirect action to elevate the serum corticosterone levels.

Genetic susceptibility to MS: a second stage analysis in Canadian MS families.

Four published genome screens have identified a number of markers with increased sharing in multiple sclerosis (MS) families, although none has reached statistical significance. One hundred and five markers previously identified as showing increased sharing in Canadian, British, Finnish, and American genome screens were genotyped in 219 sibling pairs ascertained from the database of the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). No markers examined met criteria for significant linkage. Markers located at 5p14 and 17q22 were analyzed in a total of 333 sibling pairs and attained mlod scores of 2.27 and 1.14, respectively. The known HLA Class II DRB1 association with MS was confirmed (P<0.0001). Significant transmission disequilibrium was also observed for D17S789 at 17q22 (P=0.0015). This study highlights the difficulty of searching for genes with only mild-to-moderate effects on susceptibility, although large effects of specific loci may still be present in individual families. Future progress in the genetics of this complex trait may be helped by (1) focussing on more ethnically homogeneous samples, (2) using an increased number of MS families, and (3) using transmission disequilibrium analysis in candidate regions rather than the affected relative pair linkage analysis.

Head injuries in skiers and snowboarders in British Columbia.

BACKGROUND: At the Vancouver General Hospital Neurosurgical Service there have been a significant number of seriously brain injured snowboarders, seemingly out of proportion to the number of skiers. The purpose of this study was to determine whether snowboarders suffered more serious head injuries than skiers in the Vancouver catchment area. METHODS: The British Columbia Trauma Registry was searched for patients incurring head injuries while skiing or snowboarding on British Columbia mountains during the period from January 1992 to December 1997. Patients were included if they were admitted to hospital and underwent neurosurgical consultation. RESULTS: A total of 40 skiers and 14 snowboarders met the above criteria. Of the skiers, 15% sustained a severe head injury by Glasgow Coma Score, another 30% sustaining moderate head injuries, while 29% of snowboarders had a severe injury and 36% a moderate injury. A concussion was present in 60% of the skiers and 21% of the snowboarders. Snowboarders suffered an intracranial hemorrhage in 71% of the cases compared to 28% of the skiers. A craniotomy was performed acutely in 10% of skiers and in 29% of snowboarders. Three deaths occurred as a direct result of head injury, one while snowboarding. All but one of the surviving skiers were able to return home, whereas four of 13 surviving snowboarders required additional inpatient rehabilitation or transfer to another acute hospital for ongoing care. CONCLUSIONS: Snowboarders suffer more significant head injuries compared to skiers in this series and are much more likely than skiers to require an intracranial procedure. In our opinion, this indicates that additional safety measures, in particular the use of mandatory helmets, should be considered by ski areas and their patrons.

Intratumoral therapy with bleomycin for cystic craniopharyngiomas in children.

Surgical removal of cystic craniopharyngiomas in children is associated with significant operative morbidity and recurrence rates. The purpose of this study was to review our experience with a less invasive therapy, namely, intratumoral bleomycin, in the treatment of predominantly cystic craniopharyngiomas. All children with craniopharyngiomas treated at a tertiary care pediatric neurosurgical center since 1994, when bleomycin was first used, were reviewed retrospectively. Seven patients received intratumoral bleomycin therapy. Patients received 2-5 mg bleomycin per dose, 3 times per week, for 3-5 weeks as an initial course. Mean follow-up of these patients was 3 years. In 4 patients, treatment resulted in a significant decrease (>50%) in tumor size, which has remained stable. Two patients' tumors progressed and underwent resection, and 1 patient had surgical removal because of persistent headaches, although no growth of residual tumor had been noted. One patient developed peritumoral edema as a result of bleomycin therapy. Intratumoral bleomycin is a useful alternative therapy for cystic craniopharyngiomas, and may control tumor growth and delay potentially harmful resection and/or radiotherapy in young children.

The value of routine cultures of the cerebrospinal fluid in patients with external ventricular drains.

OBJECTIVE: The purpose of this study was to determine whether routine cerebrospinal fluid (CSF) bacteriological cultures in patients with external ventricular drains (EVDs) can identify infections early and prevent complications related to bacterial ventriculitis. METHODS: We retrospectively reviewed the microbiological reports and clinical data for all patients in whom an EVD was placed at a tertiary care pediatric neurosurgical center between 1984 and 1997. EVDs were inserted in the operating room or intensive care unit, and, in most patients whose EVD remained in place for more than 2 days, daily cultures of CSF were performed. RESULTS: One hundred fifty-seven patients in whom 160 EVDs had been placed were included in the study. Forty-eight positive cultures were identified, of which the majority were determined to be contaminants. Seven infections were identified on the basis of microbiological criteria (i.e., a gram-positive stain and positive culture) and a subsequent positive culture. In all patients in whom infections developed, routine daily cultures of CSF were performed, and, in each instance, these cultures failed to identify the infections before clinical changes occurred. All seven patients with infection had fever (>38.5 degrees C) and peripheral leukocytosis (>11 x 10(3)/mm3) on the day the infection was identified, and one had a change in CSF appearance. CONCLUSION: The results of this study suggest that routine culture of CSF in children with EVDs is not necessary, and that if CSF cultures are performed for new fever (>38.5 degrees C) or peripheral leukocytosis, neurological deterioration, or a change in CSF appearance, infections will be identified in a timely fashion. In situations in which these clinical indicators might be masked, routine cultures may be valuable.

Giant intraspinal pseudomeningoceles cause delayed neurological dysfunction after brachial plexus injury: report of three cases.

OBJECTIVE AND IMPORTANCE: Delayed neurological dysfunction after a brachial plexus injury is uncommon. We present the cases of three patients with a history of significant brachial plexus trauma and late neurological deterioration secondary to giant intraspinal extradural pseudomeningoceles. CLINICAL PRESENTATION: Three patients, each with a remote history of brachial plexus trauma, presented with slowly progressive upper-limb weakness. An examination revealed bilateral lower motor neuron weakness in the upper extremities in all patients and evidence of spastic paraparesis in one. Magnetic resonance imaging and postmyelogram computed tomographic scans demonstrated large anterior extradural cerebrospinal fluid collections extending from the upper cervical to lower thoracic and lumbar levels in each patient. Myelograms demonstrated a connection with the subarachnoid space in two patients. INTERVENTION: Direct obliteration of the connection between the cyst and the subarachnoid space was completed in two patients, and a cystoperitoneal shunt was placed in the third. Postoperative imaging demonstrated complete resolution of the extradural collections. Arrest of progression of upper-limb deterioration was observed in all patients, and dramatic improvement of long tract symptoms occurred in one. CONCLUSION: Giant intraspinal pseudomeningoceles are a rare complication of brachial plexus root injuries or avulsion, capable of causing significant morbidity. Early intervention can improve symptoms related to long tract involvement and prevent further deterioration of lower motor neuron disease. The pathophysiology of neurological dysfunction caused by these giant collections is unclear; however, vascular and mechanical factors thought to be important in the pathogenesis of cervical myelopathy also may have a role.

The natural history of multiple sclerosis: a geographically based study: 8: familial multiple sclerosis.

We have examined the demographics and long-term outcome of 1044 patients with sporadic and familial multiple sclerosis in a population-based cohort from London, Ontario. The mean follow-up was 25 years in duration, and by this time most patients had reached the unambiguous endpoint scores of the Kurtzke disability status scale (DSS), DSS 6, 8 or 10. An affected family member was identified in 19.8% of the total population, and this subgroup was further divided arbitrarily into the following three groups by the type and number of relatives affected: (i) first degree only; (ii) first degree plus others; (iii) second or third degree. The outcome in these groups was compared with that for those patients who, at a mean 25 year follow-up, had no relatives known to be affected. Familial cases closely resembled those remaining sporadic in both demographics and outcome, although onset in the most heavily loaded families was earlier and male/female ratio was greater. The times to DSS 6, 8 and 10 did not differ significantly when sporadic, familial and familial subgroups were compared. These results provide no clinical support for viewing familial multiple sclerosis as distinct from the sporadic form. The observed recurrence rate for siblings in a strictly defined epidemiological sample was 3.5%, much as projected. These results validate the recurrence risks which have previously been derived from age-corrected data for these first-degree relatives.

The natural history of multiple sclerosis: a geographically based study. 7. Progressive-relapsing and relapsing-progressive multiple sclerosis: a re-evaluation.

Classifications of multiple sclerosis subtypes have been largely based on clinical phenomenology. Nevertheless, definitions of relapse, remission and progression have been imprecise. Recently an international consensus group, as part of a reclassification of disease subtypes, recommended dropping the term 'relapsing-progressive' (RP) and retaining the term 'progressive-relapsing' (PR) multiple sclerosis. The term 'RP' multiple sclerosis had been applied when the early course combined both relapses and progression and was believed to identify some patients with a worse than average outcome. The PR group consisted of patients with primary progressive disease who later in their course developed relapses. Since the terminology has been largely arbitrary, we have evaluated the validity of the terms 'RP' and 'PR' multiple sclerosis in the context of long-term outcome within a large population-based cohort of progressive multiple sclerosis patients seen at the London Multiple Sclerosis Clinic (Canada) between 1972 and 1984. Mean follow-up of the entire cohort was 25 years. Designation of RP multiple sclerosis did identify a more rapidly progressive subgroup. To realign these natural history data with consensus recommendations, these patients were reassigned to secondary progressive (SP) or to primary progressive (PP) multiple sclerosis, with progression defined as at least 1 year of progressive deterioration. PP multiple sclerosis patients with relapses after a year were designated as having PR multiple sclerosis. Relapses in primary progressive multiple sclerosis occurred in 27.8% of patients at some point even two to three decades after onset. In general these relapses were mild and remitting, but served to blur the distinction between progressive and relapsing-remitting disease. The long-term outcomes of time to Kurtzke disability scores (DSS) of 3, 6, 8 and 10 were compared among the progressive subtypes. Times to these disability end-points and to death were not different between PR and PP multiple sclerosis. Survival curves for progressive patients have been amended to incorporate the reassignment of PR multiple sclerosis patients into the PP group and the RP multiple sclerosis patients into the PP and SP subgroups. The time to reach DDS 3, 6, 8 and 10 for a population-based cohort of primary and secondary progressive patients resulting from the elimination of the categories of RP multiple sclerosis and PR multiple sclerosis has been established. These results provide justification for retaining only PP and SP multiple sclerosis as the subgroups of progressive disease.

Intramedullary spinal teratoma and diastematomyelia. Case report and review of the literature.

The authors present a patient with diastematomyelia and a spinal intramedullary teratoma, remote from the split cord malformation. A split cord malformation at the L2-L3 level was initially discovered during investigations for thoracic congenital scoliosis, and this was treated surgically. The teratoma, which was at the level of the scoliosis, went undiagnosed until neurological deterioration occurred many years later. Surgical removal of the teratoma resulted in return to normal function. The potential for coexisting congenital anomalies at separate levels of the spinal cord must be considered in radiological investigations of a developmental spinal lesion.

The natural history of multiple sclerosis: a geographically based study. 5. The clinical features and natural history of primary progressive multiple sclerosis.

We report a natural history study of 216 patients with primary progressive (PP)- multiple sclerosis defined by at least 1 year of exacerbation-free progression at onset. This represents 19.8% of a largely population-based patient cohort having a mean longitudinal follow-up of 23 years. This subgroup of PP-multiple sclerosis patients had a mean age of onset of 38.5 years, with females predominating by a ratio of 1.3:1.0. The rate of deterioration from disease onset was substantially more rapid than for relapsing-remitting multiple sclerosis, with a median time to disability status score (DSS) 6 and DSS 8 of 8 and 18 years, respectively. Forty-nine percent of patients were followed through to death. Examination of the early disease course revealed two groups with adverse prognostic profiles. Firstly, a shorter time to reach DSS 3 from onset of PP-multiple sclerosis significantly adversely influenced time to DSS 8. Second, involvement of three or more neurological systems at onset resulted in a median time to DSS 10 of 13.5 years in contrast to PP-multiple sclerosis patients with one system involved at onset where median time to death from multiple sclerosis was 33.2 years. However, age, gender and type of neurological system involved at onset appeared to have little influence on prognosis. Life expectancy, cause of mortality and familial history profile were similar in PP-multiple sclerosis and non-PP-multiple sclerosis (all other multiple sclerosis patients from the total population). From clinical onset, rate of progression was faster in the PP-multiple sclerosis group than in the secondary progressive (SP)-multiple sclerosis group. When the rates of progression from onset of the progressive phase to DSS 6, 8 and 10 were compared, SP-multiple sclerosis had a more rapid progressive phase. A substantial minority (28%) of the PP-multiple sclerosis cohort had a distinct relapse even decades after onset of progressive deterioration. These studies establish natural history outcomes for the subgroup of multiple sclerosis patients with primary progressive disease.

The natural history of multiple sclerosis: a geographically based study. 6. Applications to planning and interpretation of clinical therapeutic trials in primary progressive multiple sclerosis.

The natural history of primary progressive multiple sclerosis (PP-multiple sclerosis) recently has been defined in a geographically based multiple sclerosis population. For a series of prognostically defined hypothetical entry criteria based upon current trends in presentation to the London Multiple Sclerosis Clinic, we determined the number of patients who would have been trial eligible. Using 23 year mean longitudinal natural history data, we identified the observed rate of deterioration for frequently used trial endpoints. Hypothetical entry criteria were based on the practical considerations which would attend the execution of clinical trials in progressive multiple sclerosis. We then developed a series of sample size tables giving the number of patients with PP-multiple sclerosis and the length of observation that would be required to detect a significant result (P = 0.05) for a 25, 50 and 75% decrease in the median time to progression with 80 or 90% power, with treatment efficacy based upon the ability to slow progression on the disability status score. It is expected that the considerations outlined here will prove useful for both trial design and interpretation of trials in PP-multiple sclerosis which will require multi-centre collaborative efforts.

The Mayo Clinic-Canadian Cooperative trial of sulfasalazine in active multiple sclerosis.

OBJECTIVE: To determine whether sulfasalazine is better than placebo in slowing disability progression in MS. METHODS: In this randomized, double-blind, placebo-controlled phase III trial, 199 patients with active relapsing-remitting (n = 151) or progressive (n = 48) MS were evaluated at 3-month intervals for a minimum of 3 years (94% completed 3 years of follow-up; mean follow-up, 3.7 years). MRI studies were performed at 6-month intervals on a subset of 89 patients. RESULTS: Sulfasalazine failed to slow or prevent disability progression as measured by the primary outcome (confirmed worsening of the Expanded Disability Status Scale [EDSS] score by at least 1.0 point on two consecutive 3-month visits). Sulfasalazine influenced favorably a number of secondary outcomes during the first 18 months of the trial (e.g., annualized relapse rate, proportion of relapse-free patients; progressive subgroup only: rate of EDSS progression at 1 and 2 years, median time to EDSS progression) but these positive findings were not sustained into the second half of the trial. CONCLUSIONS: Sulfasalazine does not prevent EDSS score progression in the subset of MS patients studied by this protocol. Treatments may improve relapse-related outcomes in MS, at least temporarily, without providing sustained slowing of EDSS progression. Phase III MS trials should be of sufficient length to determine a meaningful impact on disease course.

The occurrence of multiple sclerosis in the Hutterites of North America.

OBJECTIVE: To report the occurrence, clinical characteristics and genealogical analysis of multiple sclerosis in the Hutterites of North-Western United States and Western Canada. BACKGROUND: The incidence of multiple sclerosis is reported to be lower or rare in certain ethnic groups and genetic isolates and was previously observed to be absent in the Hutterite population. METHODS: After long-term surveillance, six patients were identified and clinical examinations and laboratory investigations including VER and MRI were completed. RESULTS: The six cases included two brothers, two first cousins, male and female, another male and female, all representing two of the three endogamous groups of Hutterites, are linked to two common ancestors through lines of descent dating to 1723. The individual pedigrees were analyzed from extensive genealogical records covering eight generations. CONCLUSION: The incidence of multiple sclerosis in Hutterites is low in a high risk area of North America. A specific mode of inheritance pattern has not been established and a common founder effect may play a role in the development of multiple sclerosis. The genetic contribution of the Hutterites seems greater than previously recognized.

A full genome search in multiple sclerosis.

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

A population-based study of multiple sclerosis in twins: update.

This study is a 7.5-year follow-up of a population-based series of twins with multiple sclerosis (MS) whose mean age now exceeds 50 years. The twin pairs were identified through the Canadian nationwide system of MS clinics and were drawn from a population of 5,463 patients. After 7.5 years, the monozygotic concordance rate increased from 25.9 to 30.8% and the dizygotic-like sex concordance rate from 2.4 to 4.7%. These results are very similar to those of other population-based studies and to our own modified replication twin data reported here. We interpret the data to mean that MS susceptibility is genetically influenced, and a single dominant or even a single recessive gene is unlikely to account for this effect. The difference in concordance rates suggests that at least two or more genes are operative. These data also have important implications for the nature of the environmental effect(s) in MS susceptibility. Most monozygotic twins are discordant even after a correction for age and magnetic resonance imaging findings. This unambiguously demonstrates the powerful effect of nonheritable factors.