A field method for blink reflex latency R-1 (BRL R-1) and prediction equations for adults and children
Kilburn, K.H.; Thornton, J.C.; Hanscom, B.
Electromyography and Clinical Neurophysiology 38(1): 25-31
1998
ISSN/ISBN: 0301-150X PMID: 9532430 Document Number: 492892
To develop a field worthy apparatus for blink reflex latency R-1 (BRL R-1), to compare mechanical and electrical stimulation, to define a standardized measurement of BRL R-1, to test a field worthy procedure and to produce population-based prediction equations. A special low voltage electromyographic (EMG) recording system was constructed which is uninfluenced by electrical and magnetic field. The supraorbital notches were stimulated mechanically using a small hammer and electrically using a stimulus of 2.0 ms duration and 2-5 mA 13. A computer program was developed which substracts the baseline for all data points and sums R-1 for 10 tests by identifying the noise floor or baseline of the EMG recording and the noise envelope. The beginning of R-1 and R-2 is defined as 2 times the noise amplitude of this envelope. BRL R-1 was compared after tap and after electrical stimulation in 16 subjects. Prediction equations were developed from data of 240 adults and 163 children unexposed to chemicals. Mechanically and electrically elicited mean BRL R-1 in 16 subjects was identical at 12.6 ms on the right and 12.7 ms vs 12.5 on the left. In adults, BRL R-1 depended on age. In children BRL R-1 was age, weight and height dependent. BRL R-1 elicited by supraorbital tap is field worthy, computer defined and identical to electrical BRL.