Uses and abuses of the EEG in epilepsy.

Our purpose was to indicate clinical situations in epilepsy in which the EEG provides useful information and those in which it is unhelpful and should be avoided. We performed an overview of the formal evidence available through Medline, Cochrane, and the Internet, as well as a traditional review based on the questions commonly asked of the authors department in a London teaching hospital. We found that there is insufficient high-quality evidence to informed decisions regarding EEG utility. The EEG has many uses in epilepsy but, without attention to detail in the referral, may be abused. Good liaison between the referrer and the EEG department is essential to make proper use of the EEG.

An integrated system for multidisciplinary assessments in stroke rehabilitation.

BACKGROUND AND PURPOSE: There is increasing emphasis on the use of integrated systems for timely, accurate, and efficient data collection for a range of service, audit, quality, and research applications. The present study evaluates the acceptability and the quality of data collected on a ward-based system over a 6-month period. METHODS: A multidisciplinary system specific for stroke rehabilitation was used. Members of each discipline were required to enter demographic, medical, nursing, therapy, and psychosocial data as appropriate to their specialty. A users' survey was undertaken at the beginning and at the end of the study. The quality and completeness of data entry were assessed by a "snapshot" of the database at the end of the study period. Primary users (n = 13) included physicians, nurses, and therapists. RESULTS: The user survey at the end of the evaluation showed a significant increase in confidence in using the system. Although the frequency of use had increased, the time spent in data entry had decreased significantly. The increase in work load, estimated at 15 to 60 minutes per week, was considered to be balanced by the benefits in patient care, audit, and research. There were 67 medical and 1046 other assessments on 67 patients entered into the system. Seven patients (11%) had incomplete medical records. Nursing and therapy assessments had been entered for all patients at admission and on discharge, with more than 95% of all possible assessments monitoring recovery being recorded accurately compared with conventional records. CONCLUSIONS: The study showed that it was possible to introduce a computerized multidisciplinary assessment system on rehabilitation wards as a part of day-to-day work without the need for significant extra resources.

The use of sinusoidal and ramp stretch stimuli in characterizing fusimotor effects on cat muscle spindles.

Comparisons were made between the results of testing muscle spindle primary afferents with low-frequency, large-amplitude sine waves of muscle stretch and with repeating ramp-and-hold stretches. Three different situations were explored, namely, activation with succinylcholine (SCh), generation of various fusimotor outflow patterns by brainstem stimulation and fusimotor activation by stimulation of single ventral root gamma-axons. With ramp-and-hold stretches the effects of bag1 fibre contraction were thought to be generally better represented by increases in the dynamic response to stretch (delta DD) than by increases in dynamic index. The equivalent effect on the sine wave response was an increase in the magnitude of the fitted sine (delta Mag). Static effects were best measured by increases in the initial frequency for ramps (delta IF) and by increases in the fitted centre frequency (delta CF) for sines. There was good agreement between sine and ramp testing in the case of SCh effects, but much less consistency during brainstem stimulation. Sine wave testing can be regarded as less efficient than ramp testing in distinguishing between static and dynamic actions because dynamic fusimotor stimulation causes equal rises in CF and Mag, but fourfold larger rises in DD than in IF. Ramp responses with combined dynamic and static fusimotor stimulation showed increases of both IF and DD as expected, but whilst sine wave responses always showed increase in CF, they often showed no increase in Mag. Comparisons of the effects of SCh, central stimulation and fusimotor stimulation showed that it is important to recognize the different effects of chain and bag2 intrafusal fibre activation as components of static fusimotor excitation. Stimulation of driving static axons (chain activation) raised the IF and CF often with 1:1 or 1:2 driving during the shortened phase of ramps and sines. However, the stretch response in both cases was either unchanged or reduced. Stimulation of a non-driving static fusimotor axon (bag2 activation) caused a marked rise in CF for sine waves and a fall in Mag, but a modest increase in ramp stretch sensitivity (DD) with no increase in dynamic index. A way is described for measuring flattening of sine wave responses as a possible way of detecting chain fibre activation. The consequences of these findings are discussed in relation to previous reports of the use of sine wave testing for assessing fusimotor mechanisms.

The effect of succinylcholine on cat gastrocnemius muscle spindle afferents of different types.

1. A population of 269 gastrocnemius muscle spindle afferents have been studied in anaesthetized cats for the effects of succinylcholine (SCh) on their response to ramp and hold stretches repeated every 6 s. The effectiveness and reliability of the SCh test was improved by prior stimulation of the muscle at 10 Hz for 30 s to increase the blood flow. 2. Responses have been assessed from averaged cycle histograms before and after a single I.V. dose of SCh of 200 micrograms kg-1. As for previous studies of jaw muscle spindles the basic measurements were initial frequency (IF), peak frequency (PF) and static index (SI), the frequency 0.5 s after the end of the ramp of stretch. Dynamic difference (DD = PF-IF), dynamic index (DI = PF-SI) and static difference (SD = SI-IF) were derived from these and increases caused by SCh indicated by the prefix delta. 3. delta DD and delta IF were each distributed bimodally and since they were uncorrelated formed the basis for a four-way classification. Since delta DD can be attributed to activation of bag1 (b1) intrafusal fibres and delta IF to bag2 (b2) fibres, while all afferents receive input from chain (c) fibres it is proposed as with the jaw spindles that the classes correspond to predominant influence from b1c, b1b2c, b2c and c intrafusal fibres. 4. The proportion of units in the different groups were similar to those in the jaw muscles except for there being very few b1c type in gastrocnemius. 5. Conduction velocity was bimodally distributed with the best dividing line at 63.2 m s-1. The b1b2c units were all, save one, in the fast group, while the b2c units were equally divided between fast and slow. 6. Mean control values for DD did not differ between the b1b2c and the b2c groups, which is taken to indicate that the b1 fibre does not contribute significantly to the dynamic stretch response of spindles with no intrafusal contraction. 7. The results emphasize the importance of recognizing that some apparently primary afferents lack b1 fibre influence, while many secondaries have marked b2 fibre influence. 8. The importance of the SCh classification is discussed in relation to the identification of fusimotor effects on spindle discharge and in relation to studies of central connectivity.