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Biomedical subjects

D G Brunet

Publications and source records attributed to D G Brunet.

11 recordsLinked to original sources
PubMed2005

The Paced Auditory Serial Addition Test: to what extent is it performed as instructed, and is it associated with disease course?

One commonly used outcome measure in multiple sclerosis (MS) clinical trials is the Multiple Sclerosis Functional Composite, which includes the Paced Auditory Serial Addition Test (PASAT) as a measure of cognitive function. Concerns have been raised about the standard PASAT scoring method, whereby the number of correct responses is summed. This method does not take into account whether the test is performed as intended, which may affect interpretation of the results. Accordingly, another scoring method has been proposed, which examines the number of times a correct response is immediately preceded by another correct response (termed a dyad). We compared the two scoring methods for the PASAT, and found that the mean percentage of correct responses not accounted for by dyads ranged from 27.5% to 49.5%, indicating that much of the time the test is not performed as instructed. We also examined disease course and the PASAT score, as studies have produced conflicting results as to whether disease course is associated with cognitive impairment. Although disease course was significantly associated with the PASAT score, it accounted for little of the variation in scores, even when adjusting for other predictors. Finally, as 14.2% of participants refused to do the PASAT or failed to complete it, we also examined whether the Perceived Deficits Questionnaire (PDQ), a self-reported measure of cognitive function, is a potential proxy measure for the PASAT. The correlation between the two tools was low (-0.14), suggesting that the PDQ is not a useful substitute for the PASAT.

Adult↗
PubMed2001

Characteristics of responders and nonresponders to brief-pulse right unilateral ECT in a controlled clinical trial.

In a double-blind, randomized controlled study of electroconvulsive therapy (ECT) in patients with major depression, 7 of the 17 patients allocated to the right unilateral group failed to respond to treatment. The nonresponders were subsequently openly treated with bitemporal treatment, which produced an acceptable outcome in these cases of right unilateral treatment failure. This paper describes the clinical outcome, electrophysiological characteristics (impedence, estimated seizure threshold, and change in threshold), and the degree to which stimuli exceeded threshold in the responder and nonresponder groups. Responders had lower seizure thresholds and longer seizures than nonresponders. In comparison with nonresponders, responders showed trends toward greater impedance and treatment at a somewhat greater degree above threshold during the first few treatments. Threshold change with treatment was found not to be related to clinical outcome. Early identification of patients likely to respond to low-dose right unilateral ECT, together with the avoidance of benzodiazepine prescription during ECT, may permit many patients to receive low-dose right unilateral ECT successfully and with a minimum of cognitive impairment.

Adult↗
PubMed2001

Regional access to acute ischemic stroke intervention.

BACKGROUND AND PURPOSE: Benefit-risk ratios from recombinant tissue plasminogen activator (rtPA) therapy for acute ischemic stroke demonstrate lack of efficacy if intravenous administration is commenced beyond 3 hours of symptom onset. We undertook to enhance therapeutic effectiveness by ensuring equitable access to rtPA for patients affected by acute ischemic stroke within a 20 000 km(2) population referral base served by a tertiary facility. METHODS: Representatives of all provider groups involved in emergency medical services developed a Regional Acute Stroke Protocol (RASP), a coordinated regional system response by dispatch personnel, paramedics, physicians, community service providers, emergency and inpatient staff in community hospitals, and the tertiary facility acute stroke team. RESULTS: As of July 26, 1999, all ambulance services in Southeastern Ontario began bypassing the closest hospital to deliver patients meeting the criteria for the RASP to the Kingston General Hospital. At 12 months, approximately 403 ischemic strokes have occurred in the region, the RASP has been activated 191 times, and 42 patients have received rtPA. CONCLUSIONS: We conclude that (1) acute stroke patients in Southeastern Ontario have improved access to interventions for stroke care; (2) geography of the region is not a barrier to access to interventions for patients with acute stroke; and (3) acute ischemic stroke patients treated with rtPA account for 5% of all acute strokes and 10% of all ischemic strokes in this region.

Aged↗
PubMed2000

Autonomic circulatory and cerebrocortical responses during increasing depth of propofol sedation/hypnosis in humans.

PURPOSE: To describe the relative effects of graded central nervous system (CNS) depression, using increasing propofol infusion rates, on neurovegetative brainstem-mediated circulatory control mechanisms and higher cortical activity in healthy humans. METHODS: Propofol was administered using an infusion scheme designed to achieve three target blood concentrations in ten healthy volunteers. Blood propofol concentrations and sedation scores were determined at baseline, during the three propofol infusion levels, and 30 min into the recovery period. Electroencephalographic (EEG) power was measured in three frequency bands to quantify cortical activity, and autonomic heart rate control was quantified using spontaneous baroreflex assessment and power spectral analysis of pulse interval. RESULTS: Sedation scores closely paralleled propofol blood concentrations (0, 0.53 +/- 0.34, 1.24 +/- 0.21, 3.11 +/- 0.80, and 0.96 +/- 0.42 microg x mL(-1) at baseline, three infusion levels and recovery respectively), and all subjects were unconscious at the deepest level. Indices of autonomic heart rate control were decreased only at the deepest levels of CNS depression, while EEG effects were apparent at all propofol infusion rates. These EEG effects were frequency specific, with power in the beta band being affected at light levels of sedation, and alpha and delta power altered at deeper levels. CONCLUSIONS: The results of this study support a relative preservation of neurovegetative circulatory control mechanisms during the early stages of CNS depression using gradually increasing rates of infusion of propofol. Indices of circulatory control did not reliably reflect depth of sedation.

Adult↗
PubMed1998

Do QEEG topographic map data have a multivariate normal distribution? Implications for tests of individual maps.

The study was designed to test whether topographic map data expressed in log power units have a multivariate normal (MVN) distribution in a healthy population, and to determine if any deviation from normality poses serious difficulties for the use of standard multivariate statistical tests in assessing the significance of deformations of the map in individual cases. Data on 361 healthy adults using 20 electrodes in the classic 10/20 configuration were recorded in six frequency bands. The log-transformed power data were shown to deviate markedly from MVN. The actual distributions of multivariate tests were computed for the sample using the 'jackknife' method, and shown to deviate markedly from the F-distributions that would be expected for MVN data. These 'jackknife' sampling distributions were then used to demonstrate significant deformations in the topographic maps of a patient who had sustained traumatic head injury.

Adolescent↗
PubMed1996

Measurement of health-related quality of life in multiple sclerosis patients.

BACKGROUND: Patient outcomes in multiple sclerosis (MS) have generally been measured by their neurological impairment using specific scales such as the Kurtzke Expanded Disability Status Scale (EDSS). However, this scale does not measure the multiple dimensions of health-related quality of life (HRQOL) such as functional status and general well-being, which are also important outcomes along with disease-specific measurements. METHODS: HRQOL was measured in a group of 97 MS patients using the RAND 36-item Health Survey 1.0. The EDSS score was assigned by the clinic neurologist. Additional data were collected from the clinical record for each patient. RESULTS: MS patients scored poorly in a number of HRQOL domains such as physical and role functioning and energy or vitality. Disability as quantified by the EDSS correlated only with the physical functioning domain. Regression models were developed to measure the relationship between patient characteristics (independent variables) and HRQOL domains (dependent variables). DISCUSSION: A number of patient characteristics were associated with higher or lower scores on the HRQOL domains. Of particular interest is the finding that a family history of MS was associated with poorer physical and social functioning as well as more pain and less vitality. The occurrence of seizures had a negative impact on role functioning, social functioning and general health perceptions. HRQOL gives caregivers a broader measure of disease burden than the EDSS alone, and should be useful in planning and monitoring interventions.

Adult↗
PubMed1994

Upper limb pain in chronic demyelinating polyneuropathy: electrophysiological correlates.

Pain is not usually considered a symptom of chronic relapsing demyelinating polyneuropathy. We report two patients with chronic demyelinating polyneuropathies in whom clinical and electrophysiological worsening was associated with the development of deep and distressing upper limb aching discomfort. One patient had a MGUS-associated hypertrophic demyelinating and prednisone-dependent polyneuropathy, followed over a course of two and a half years. His discomfort regularly predicted electrophysiological relapse of neuropathy, before more obvious clinical signs had emerged. Resolution of the discomfort also predicted subsequent clinical and electrophysiological improvement. Upper limb pain may be an important feature of early relapse in some patients with demyelinating polyneuropathies. Standardized serial electrophysiological testing in patients with chronic demyelinating polyneuropathy can be an important management tool in conjunction with clinical signs and symptoms.

Arm↗
PubMed1988

Lupus anticoagulant, antiphospholipid antibodies and migraine.

The records of fifteen patients referred for neurological assessment and found to have lupus anticoagulant or elevated anticardiolipin antibodies were reviewed. The mean age for females in the group was 29.4 years and for males was 35. A diagnosis of migraine, either as an acute or chronic problem, was made in 10 (66%) of these patients. Seven of the 15 patients had ischemic stroke and two patients had other thrombotic complications associated with lupus anticoagulant. Three of the nine female patients with migraine had histories of spontaneous abortions. All migraine patients experienced transient or more prolonged neurological deficits with their headaches. An association between lupus anticoagulant and migraine can only be suggested. Data on the incidence of migraine in patients with lupus anticoagulant in the general medical population does not exist. Furthermore the prevalence of lupus anticoagulant in migraine sufferers is unknown. Therefore further studies are required to investigate this possible association.

Adult↗
PubMed1986

The value of prolonged electroencephalographic and video monitoring in diagnosis of seizure disorders.

Prolonged electroencephalographic and video monitoring of ictal events is useful in aiding the diagnosis of complicated seizure disorders. Forty-eight patients admitted to a neurology service were assessed with this technique. Twenty-five (54%) had their diagnoses changed, six (14%) had their diagnoses confirmed and the remaining patients had inconclusive studies. Therapy is modified by the results and in addition both patient and staff education is enhanced through the use of this equipment.

Adolescent↗