Interfacing the Olivetti P101 and Biomac 500 computers to extend a method of E.M.G. analysis

EMG-interference pattern analysis

The EMG interference pattern, built up of single motor unit action potentials, may be analyzed subjectively, or objectively by computer aided, quantitative methods, like counting of zero-crossings, counting of spikes, amplitude measurements, integration of the area under the curve, decomposition techniques, power spectrum analysis and turn/amplitude analysis. Since the shape of the interference pattern of healthy muscles is dependent on age, sex, force, muscle, temperature, fatigue, fitness level, recording site and surrounding tissue, electrode type, sensitivity, filters, sampling frequency and threshold level, all methods of analyzing the IP have to be standardized. Quantitative methods of analyzing the EMG interference pattern may be used for monitoring botulinum toxin therapy of dystonia and spasticity, quantifying spontaneous activity, assessment of chronic muscle pain, neuro-urological and proctological function, and diagnosing neuromuscular disorders. For diagnostic purposes, the methods favored are those that use needle electrodes and do not require measurement or monitoring of muscle force. The most well-evaluated methods are those using turn/amplitude analysis, like the cloud methods and the peak-ratio analysis. Peak-ratio analysis has the advantage that reference limits are easy to obtain and that its utility is well established and confirmed by several investigations. Overall, automatic methods of EMG interference pattern analysis are powerful tools for diagnostic and non-diagnostic purposes.

Automatic analysis of the electromyogram in healthy subjects of different ages

The technique of automatic analysis of the electromyogram is reviewed in detail. Observations on new series of healthy subjects which may serve as a control series for comparisons with subjects with neuromuscular disease are reported. The advantages to clinical practice of using fixed standard loads for the examination are stressed. Increase in the mean amplitude of the interference pattern wasfound with increasing age in biceps brachii and tibialis anterior (but not in vastus medialis). There was no corresponding increase in mean turns count. It is suggested that this change is due to increasing mild chronic partial denervation in these 2 muscles with advancing age.