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Biomedical subjects

Michael Swash

Publications and source records attributed to Michael Swash.

12 recordsLinked to original sources
PubMed2003

Motor responses evoked by transcranial magnetic stimulation and peripheral nerve stimulation in the ulnar innervation in amyotrophic lateral sclerosis: the effect of upper and lower motor neuron lesion.

We studied the upper (UMN) and lower motor neuron (LMN) innervations of 159 hands from 81 patients with amyotrophic lateral sclerosis (ALS). Eleven patients with various chronic LMN disorders causing weakness in the abductor digiti minimi (ADM) muscle served as LMN controls. Thirty healthy subjects served as normal controls. Cortical motor threshold, central conduction time (CMCT), and motor-evoked response amplitude (MEP) after transcranial magnetic stimulation (TMS) were studied, and the MEP/M wave ratio was calculated. The data was analyzed in the ALS subjects in groups defined by ADM muscle strength and by the presence or absence of clinical signs of UMN involvement. CMCT was not increased in the ALS or LMN disease groups. The threshold was higher in limbs with both weak ADM muscles and UMN signs. The MEP/M wave amplitude ratio was increased in weak muscles in the ALS patients, notably in limbs with no UMN signs, and also in weak muscles in patients with other chronic LMN disorders. It was frequently decreased in strong muscles. There was no difference between bulbar-onset and limb-onset ALS groups, and there was no correlation between threshold and disease duration. We suggest that expressing the data as an index and utilising the MEP/M wave amplitude ratio as a variable is a sensitive method for detecting UMN abnormality in ALS in particular in early affected muscles.

Adult↗
PubMed2003

Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis.

There is a need for a sensitive neurophysiological measure of disease progression in following the course of patients with amyotrophic lateral sclerosis (ALS). We studied two groups of nine ALS patients, one with slow progression (Group A) and the other with rapid progression (Group B). We evaluated muscle strength scores using the Medical Research Council (MRC) scale in limb and trunk muscles, forced vital capacity (FVC), and ALS functional rating scale (ALS-FRS) scores. Maximal voluntary isometric contraction (MVIC) of the abductor digiti minimi muscle (ADM) was measured, using a digital device. We also measured M-wave amplitude and area in the ADM, and the distal motor latency and F-wave frequency in the ulnar nerve; from these data, the neurophysiological index (NI) was calculated, as described previously. In both groups, the NI was the most sensitive measure of change, with the smallest coefficient of variation. We conclude that the NI, which requires no special technology and no new clinical or technical skills to use, is sensitive to change, and therefore may be useful in clinical trials, as well as in a clinical setting.

Adolescent↗
PubMed2003

Factors which predict physical and mental health status in patients with amyotrophic lateral sclerosis over time.

OBJECTIVES: To determine which factors are predictive of physical and mental health one year after a first measurement of health status in amyotrophic lateral sclerosis (ALS) patients. METHODS: The Physical Component Summary (PCS) score and the Mental Component Summary (MCS) score of the SF-36 were used as the main outcome measures in patients enrolled in the European ALS Health Profile Study (ALS-HPS). Correlation and stepwise regression procedures were used to determine the relationship between patients' physical and mental health status at follow-up with baseline measures. RESULTS: A total of 1118 patients were recruited into the ALS-HPS, of which 918 (82.11%) returned fully or partially completed baseline and follow-up surveys. PCS scores declined over time. No significant changes were reported for the MCS scores over time for patients with ALS. Baseline scores were found to be significant predictors of patients' health status over time. CONCLUSIONS: Overall, patients' physical health status at the time of recruitment was the major predictor of the physical health status at both first and second follow-up time assessments. The same relationship was found between baseline and follow-up mental health status. The study also confirms the appropriateness of the use of the SF-36 in ALS patients.

Activities of Daily Living↗
PubMed2003

Hospital founders.

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History, 17th Century↗
PubMed2002

What does the neurologist expect from clinical neurophysiology?

The future role of clinical neurophysiology is considered in the light of its achievements. It is argued that there is a need to develop methods for specific diagnosis, especially in neuropathies. There is also an unmet requirement for the development of techniques for the prediction of treatment outcomes and for the measurement of changes during the natural history of neuromuscular disorders and their treatment. These issues are not addressed by currently available clinical test methods.

Electromyography↗
PubMed2002

Use of the short form health survey (SF-36) in patients with amyotrophic lateral sclerosis: tests of data quality, score reliability, response rate and scaling assumptions.

OBJECTIVES: To evaluate response rate, data quality, score reliability and scaling assumptions of the 36 item Short Form Health Survey (SF-36) in a large scale pan European survey of amyotrophic lateral sclerosis (ALS) patients. DESIGN: A questionnaire based survey of patients diagnosed with ALS across 15 European countries. SAMPLE PATIENTS: presenting at neurological clinics for treatment of their condition were asked to partake in the survey. RESULTS: 948 patients have been recruited into the survey, from whom responses have been gained in 754 (79.5%). Scores on the eight dimensions of the SF-36 were found to manifest high internal consistency reliability. Items were, in most instances, found to be most highly correlated with their own (corrected) scale score than with other scale scores. However, on two dimensions (role-physical and role-emotional) there was high levels of missing data, together with substantial floor and ceiling effects. The two factor model (of underlying constructs of physical and emotional health) for the SF-36 suggested by the developers was not supported in this patient group. CONCLUSION The SF-36 appears to provide reliable information for this patient group, and for the most part there are high levels of item completeness and good spread of scores. This is not, however, true for the role functioning dimensions. Furthermore, the underlying two factor model for the SF-36 was not supported. The implications for measuring health status in this patient group are discussed.

Aged↗
PubMed2002

F-Waves and the corticospinal lesion in amyotrophic lateral sclerosis.

INTRODUCTION: In upper motor neuron (UMN) syndromes, F-waves are of higher amplitude, increased duration, and increased latency. Increased F-wave frequency in UMN syndromes is not well documented. We have studied the effect of corticospinal lesion on F-wave frequency, M-wave amplitude, distal motor latency and on the Neurophysiological Index (CMAP amplitude/DML x % F-wave frequency) which we have described previously in amyotrophic lateral sclerosis (ALS). METHOD: We studied 145 abductor digiti minimi (ADM) muscles in 75 patients with ALS. Six groups of hands were defined, based on strength of the ADM, as assessed clinically by the MRC scale, and the presence or absence of UMN signs in the same upper limb. RESULTS: CMAP amplitude and area were decreased, and DML increased, in weaker muscles (MRC < 3) causing a change in the ALS Neurophysiological Index. In general, UMN signs were not correlated with increased F-wave frequency. In five weak hands F-responses were studied in individual motor units. A larger number of responding motor units in these weak limbs with UMN signs was observed. CONCLUSION: F-wave excitability is largely dependent on the size of the lower motor neuron pool.

Action Potentials↗