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J D Fisk

Publications and source records attributed to J D Fisk.

At least 19 recordsLinked to original sources
PubMed2005

A comparison of health utility measures for the evaluation of multiple sclerosis treatments.

OBJECTIVES: To evaluate the practical application and psychometric properties of three health utility measures in a sample of MS patients with a broad range of neurological disability as measured by the Extended Disability Status Scale (EDSS). METHODS: Patients randomly selected from two MS clinic registries were assessed using standard clinical methods and completed three generic measures of health utility (EQ-5D, HUI Mark III, SF-6D). The proportion of missing data, test/retest reliability, and construct validity of each health utility measure were examined. RESULTS: The assessments were completed by 187 patients. Less than 10% of data were missing for the subscales of the SF-6D (< 3.2%), HUI Mark III (<1.6%), and EQ-5D (< or =7.5%). Severely disabled patients were more likely to omit physical function questions for the SF-6D (20%), and EQ-5D (43%). Retest reliability for the SF-6D (ICC = 0.83), EQ-5D (ICC = 0.81), and HUI Mark III (ICC = 0.87) were adequate for population surveys. Correlations between assessment of clinical function and each health utility measure were strongest for the HUI Mark III (HUI Mark III EDSS rho = -0.77, HUI Mark III ambulation index rho = -0.76, HUI Mark III timed 25 foot walk rho = -0.73, HUI Mark III nine hole peg test rho = -0.65). CONCLUSIONS: The health utility measures were generally feasible and reliable but the HUI Mark III demonstrated highest concordance with the EDSS across the full range of neurological disability. Of the three measures studied, the HUI Mark III may be the most appropriate for cost effectiveness evaluations of MS therapies.

Adjuvants, Immunologic↗
PubMed2005

Outcomes of incident mild cognitive impairment in relation to case definition.

Definitions of mild cognitive impairment (MCI) vary, yielding conflicting results. For example, case definitions affect prevalence but not outcomes in prevalent cases. Our objective was to determine whether variation in case definitions affects outcomes in incident cases of MCI. The 5 year risks of death, institutionalisation, and dementia were evaluated in clinically examined incident MCI cases in the Canadian Study of Health and Aging. The definition of MCI was varied so as to include or relax combinations of diagnostic features from consensus criteria. Relative risks (RR) of each adverse outcome were highest in MCI case definitions that required subjective memory complaints (for example, RR of dementia = 26.4-38.7). Although each MCI definition conferred an increased risk of dementia, for each case definition 20-30% of survivors had no cognitive impairment at follow up. In this population based study, MCI represented a transitional state, but was heterogeneous, with substantial proportions recovering, regardless of how MCI was defined. Factors associated with recovery and non-progression in MCI require elucidation.

Activities of Daily Living↗
PubMed2003

Short term predictors of unemployment in multiple sclerosis patients.

BACKGROUND: Unemployment is common in people with multiple sclerosis (MS) and is associated with loss of income and impaired health related quality of life. This study determined variables associated with unemployment and risk factors for the development of unemployment in people with MS. METHODS: Ninety-six patients who were under age 65 and participated in two previous studies to measure economic costs and health related quality of life in MS were included. The baseline employment rate and variables associated with unemployment at baseline were determined. The ability of these variables to predict unemployment over the next two and a half years was then evaluated. RESULTS: At baseline 50.1% (50/96) of participants were employed. Two and a half years later only 40.6% (39/96) remained employed. This represents loss of employment for 22.0% (11/50) of those originally employed. Factors associated with unemployment at baseline included greater disability, progressive disease course, longer disease duration, and older age. Risk factors for loss of employment over the next 2.5 years included greater disability and older age. CONCLUSIONS: This study confirms the low employment rate among people with MS and confirms the association of several previously-reported factors with greater risk of unemployment. It is also the first study to confirm that some of these factors also increase the risk of future unemployment. People with MS who are over age 39 or have moderate disability and are still employed can now be identified as at risk for becoming unemployed over the next 2.5 years. They should be considered for interventions to maintain employment or to lessen the impact of unemployment.

Adult↗
PubMed2002

The relation between APOE status and neuropsychological memory test performance: an analysis of the Canadian Study of Health and Aging.

This study examined the relationship between two risk factors for dementia, the apolipoprotein (APOE) epsilon4 allele and poor memory test performance. Participants were from the Canadian Study of Health and Aging, a 4-year longitudinal population-based study. Persons with no cognitive impairment who had an epsilon4 allele but whose memory was average or better were not at increased risk of developing dementia after five years. Risk was increased for those with below average memory and no epsilon4 allele, but was particularly increased for those with below average memory and an epsilon4 allele. While the APOE epsilon4 allele was associated with slightly lower memory test performance for persons without cognitive impairment at baseline, it only increased their risk of developing dementia if their memory was below average.

Aged↗
PubMed2001

Limitations of the Paced Auditory Serial Addition Test as a measure of working memory in patients with multiple sclerosis.

The Paced Auditory Serial Addition Test (PASAT) is a commonly used procedure that combines elements of both a working memory task and a test of information processing speed. Patients with multiple sclerosis (MS) have consistently been found to be impaired on this test and it has been recommended as a core outcome measure in clinical trials. The standard score for this task is the number of correct responses at each stimulus presentation rate but a concern has been raised that subjects may ignore some test items in order to chunk the information into manageable portions and avoid performing several cognitive tasks simultaneously. To account for this strategy, one can examine the proportion of correct responses that are consecutive (termed dyads), since such responses require that the task be performed according to the instructions. We compared a group of 35 mildly to moderately disabled MS patients and matched healthy controls on the PASAT. The MS patients made significantly fewer correct responses at the 2 slowest presentation rates (2.4, 2.0 s/digit) while their scores at faster rates (1.6, 1.2 s/digit) did not discriminate them from controls as well. Nevertheless, the MS patients' percentage of dyads was significantly lower than that of the control sample across all stimulus presentation rates. While our study supports the use of the PASAT as a test that distinguishes MS patients from healthy individuals, our results also illustrate problems that lie in the interpretation of this difference in performance. It appears that a chunking strategy may be common in the PASAT, particularly as task demands increase, and that this may mask actual performance differences. If so, the total correct response score alone is limited as a measure of working memory and information processing speed. More detailed analyses of PASAT performance, coupled with other measures of information processing, may help clarify the underlying cognitive deficits of MS patients.

Adult↗
PubMed2001

Improved detection of differential information-processing speed deficits between two disease-course types of multiple sclerosis.

Patients with multiple sclerosis (MS) frequently demonstrate impairments of information-processing speed (IPS) on measures such as the Paced Auditory Serial Addition Test (PASAT; D. M. A. Gronwall, 1977). The authors have previously shown that their new PASAT scoring method (mean dyad score) is better correlated in comparison with more traditional PASAT scoring method(s), with magnetic resonance imaging measurement of the total area (mm2) of white-matter sclerotic lesions (P. J. Snyder & J. C. Cappelleri, 2001). The present study reports that the mean dyad score discriminated 20 relapsing-remitting MS (RRMS) patients from 15 secondary-progressive MS (SPMS) patients noticeably better than did the standard scoring method(s). Mean dyad scores < 4.13 classified patients as having SPMS with 73% accuracy (sensitivity), whereas scores > or = 4.13 classified patients as having RRMS with 80% accuracy (specificity).

Adult↗
PubMed2000

Promotion of sheet formation in alpha-peptide strands by a beta-peptide reverse turn.

[structure: see text]We show that a tetrapeptide with a heterogeneous backbone, i.e., with two different classes of amino acid residues, adopts a hairpin conformation in which each type of residue plays a different structural role. The alpha-residues at the ends form hydrogen bonds characteristic of antiparallel beta-sheet secondary structure, while the central di-beta-peptide segment forms a reverse turn. The configuration of the turn residues is critical to sheet formation.

Magnetic Resonance Spectroscopy↗
PubMed2000

Cost-effectiveness of interferon beta-1b in slowing multiple sclerosis disability progression. First estimates.

OBJECTIVE: To estimate the cost-effectiveness (CE) of interferon beta-1b (IFN beta-1b) in slowing disability progression in persons with relapsing-remitting multiple sclerosis (RRMS). METHODS: Treatment program costs and health outcomes are modeled for cohorts of 1,000 females and 1,000 males followed 40 years from onset. Fifteen scenarios model MS natural history progression, treatment efficacy, direct treatment costs, and MS healthcare costs. A single randomized placebo-controlled trial of IFN beta-1b found reduced disease activity by MRI, reduced frequency and severity of exacerbations, and a tendency toward slower disability progression. Disability years avoided are modeled as the primary health outcome analyzed. A ministry of health (MOH) perspective is adopted, using Nova Scotia population-based data. Annual IFN beta-1b direct treatment costs (Can $16,685) are high relative to both MOH healthcare costs per person with MS (Can $2,000) and estimated MOH costs avoided. RESULTS: Given "reference case" assumptions for women with RRMS, treatment reduces lifetime disability years by 10%. Cost per disability year avoided before discounting is Can $189,230 (US $124,892), and Can $274,842 (US $181,395) after discounting at 5%. Estimates for alternative scenarios vary greatly, leaving main findings unchanged. CONCLUSIONS: Using the Expanded Disability Status Scale, cost per disability year avoided due to interferon beta-1b treatment in RRMS is quite high. Comparable CE estimates, using MS-specific or generic health-related quality-of-life outcome measures, are even higher. Further research is required to better measure treatment effects, modification of MS natural history, and net societal costs of IFN beta-1b in RRMS.

Adjuvants, Immunologic↗
PubMed2000

Information processing efficiency in patients with multiple sclerosis.

Reduced information processing efficiency, consequent to impaired neural transmission, has been proposed as underlying various cognitive problems in patients with Multiple Sclerosis (MS). This study employed two measures developed from experimental psychology that control for the potential confound of perceptual-motor abnormalities (Salthouse, Babcock, & Shaw, 1991; Sternberg, 1966, 1969) to assess the speed of information processing and working memory capacity in patients with mild to moderate MS. Although patients had significantly more cognitive complaints than neurologically intact matched controls, their performance on standard tests of immediate memory span did not differ from control participants and their word list learning was within normal limits. On the experimental measures, both relapsing-remitting and secondary-progressive patients exhibited significantly slowed information processing speed relative to controls. However, only the secondary-progressive patients had an additional decrement in working memory capacity. Depression, fatigue, or neurologic disability did not account for performance differences on these measures. While speed of information processing may be slowed early in the disease process, deficits in working memory capacity may appear only as there is progression of MS. It is these latter deficits, however, that may underlie the impairment of new learning that patients with MS demonstrate.

Adult↗
PubMed1999

A prospective analysis of cognitive function and anticardiolipin antibodies in systemic lupus erythematosus.

OBJECTIVE: To prospectively analyze the association between changes in cognitive function and circulating anticardiolipin antibodies (aCL) over a period of 5 years in patients with systemic lupus erythematosus (SLE). METHODS: Cognitive function was assessed in 51 unselected female SLE patients at baseline and after a mean followup of 64.5 months (range 52-71 months), using standardized tests of cognitive function, i.e., the Wechsler Adult Intelligence Scale-Revised, the Wechsler Memory Scale-Revised, and the California Verbal Learning Test. Circulating IgG, IgA, and IgM aCL and anti-double-stranded DNA (anti-dsDNA) antibody levels were determined by enzyme-linked immunosorbent assay on 4-7 occasions over the same time period. Persistent antibody reactivity was defined as levels more than 2 standard deviations (moderately positive) and more than 5 standard deviations (highly positive) above the mean for normal controls over the duration of the study. Changes in overall cognitive performance and in raw scores on individual cognitive tests were compared in patients who were persistently positive or negative for aCL. RESULTS: At baseline 11 patients (22%) were cognitively impaired, compared with 7 (14%) at followup. Between 16% and 37% of patients had persistently elevated aCL levels of different isotypes. There was no significant difference in the prevalence of overall cognitive impairment in patients who were persistently positive for aCL compared with those who were not. In contrast, over the period of study, patients who had persistent IgG aCL positivity had a reduction in psychomotor speed, and patients who had persistent IgA aCL positivity had a reduction in conceptual reasoning and executive ability. Similar associations with anti-dsDNA antibodies were not found. CONCLUSION: These results suggest that IgG and IgA aCL may be responsible for long-term subtle deterioration in cognitive function in patients with SLE.

Adult↗
PubMed1999

Assessing the ADL functioning of persons with Alzheimer's disease: comparison of family informants' ratings and performance-based assessment findings.

The activities of daily living (ADL) functioning of 26 subjects with Alzheimer's disease was measured using the Assessment of Motor and Process Skills (AMPS) and family informants' Older Americans Resources and Services (OARS) Activities of Daily Living (ADL) reports. Concordance with a clinician's ratings of subjects' level of ADL functioning was achieved for 77% of the subjects based on their AMPS ADL process ability measures and for 54% for the subjects based on their family informants' OARS ADL ratings. In cases of discordance, subjects' AMPS ADL process ability measures were just as likely to overestimate (11.5%) as to underestimate (11.5%) subjects' ADL functioning. In contrast, 46% of the informants overestimated their family members' ADL functioning, and this was more likely to occur when subjects' cognitive impairment was mild.

Activities of Daily Living↗
PubMed1998

Ethical guidelines of the Alzheimer Society of Canada.

Alzheimer's disease raises numerous ethical issues which vary and evolve over the course of the illness. In recognition of the need for ongoing discussion of these issues, the Alzheimer Society of Canada established a Task Force on Ethics in 1995. Through a process of "discourse ethics" and consultation on a national scale, the Task Force produced a series of guidelines dealing with the issues of: communicating the diagnosis, driving, respecting individual choice, quality of life, participation in research, genetic testing, the use of restraints, and end-of-life care. This manuscript presents a summary of these guidelines as well as a summary of the ideas on which they were based. It was the hope of the Society that the publication of these guidelines will serve to facilitate discussion of the ethics of care of those with Alzheimer's disease.

Alzheimer Disease↗
PubMed1997

Measuring functional competence in older persons with Alzheimer's disease.

Despite their limitations, mental status tests and self/proxy reports of instrumental activities of daily living (IADL) are often used to predict functional competence. In contrast, the Assessment of Motor and Process Skills (AMPS) is a direct observational assessment of IADL competence. Sixty-four community-dwelling elderly (20 Alzheimer's disease [AD] patients and 44 nondemented) were assessed with the AMPS, the Mini-Mental State Examination (MMSE), and the Older Americans Resources and Services (OARS)-IADL. Performance on all three assessments was significantly lower for the AD sample. The MMSE did not correlate significantly with the AMPS motor ability measures but it correlated modestly with the AMPS process ability measures. The OARS-IADL correlated significantly with the AMPS motor ability measure for the nondemented sample alone. Although mental status and self/proxy assessments provide some insight into individuals' IADL competence, direct observation of IADL task performance provides additional information regarding the subtle process and motor skills changes that occur in progressive dementing conditions.

Activities of Daily Living↗
PubMed1996

Conceptual reasoning as a mediator of verbal recall in patients with multiple sclerosis.

A number of intercorrelated factors, including level of neurologic impairment, age, and conceptual reasoning, appear to be related to memory performance among patients with Multiple Sclerosis (MS). A battery of neuropsychological tests was administered to 131 patients with MS ranging in age from 19 to 76 years, with a mean symptom duration of 12.3 years and an overall mild level of MS-related neurologic impairment. Regression analyses indicated that neurologic impairment and age each contributed uniquely to the prediction of delayed free recall of a word list. Furthermore, when the effect of conceptual reasoning was accounted for, neither neurologic impairment nor age were significantly related to recall. Thus, a mediated relation was confirmed, supporting the idea that a significant portion of neurologic-impairment-related and age-related differences in recall are due to differences in conceptual reasoning that are important for optimal performance on tests of recall. Additional analyses failed to support a similar mediated relation using recognition rather than recall as the measure of memory performance.

Adult↗