THE RANCHO EMG ANALYZER - A COMPUTERIZED SYSTEM FOR GAIT ANALYSIS

This paper describes a computer system which accurately defines the EM G patterns of the lower extremities during gait. Footswitches are used to identify the temporal relationships and determine the phases of th e gait cycle. Fine wire electrodes, inserted in the desired muscles of the patient being tested, provide EMG signals for comparison with a n ormal database. The system is also usable with surface electrodes when an appropriate normal database for surface electrodes is incorPorated . Descriptive qualifiers (such as 'premature onset, 'delayed cessation , 'no clinically significant EMG, 'continuous activity' etc.) are used to produce a clinically relevant printed (textual) report. The intens ity filtered average (IFA) of the EMG is shown graphically with the re presentative profile of each stride. The IFAs for all muscles tested c an be plotted together (up to six on a page) and the graphic represent ation of the 'raw' EMG can be produced. The methods of generating the normal database by creating time-adjusted mean profiles (TAMP) are enu merated. The clinical use of the system is discussed. A detailed analy sis of 31 of the most recent patient tests for which the system was us ed provides an indication of its accuracy. For 86% of the 428 muscle t ests examined, the EMG analyser was considered to have given the corre ct result as compared with a visual analysis of the raw EMG record by a trained expert. Recommendations for the use and future improvements of the EMG analyser are made.