Abstract
Purpose :
Can biasing the magnocellular pathways with pattern reversing checkerboard stimulus using successive spatial frequencies while simultaneously measuring the Visual Evoked Potential latency be an indicator of the neural impulse. If the VEP is an indicator, then can it determine dysfunction of the retina neural network represented by the loss of synchronization ot the successive differing spatial frequencies resulting from mTBI when compared to normal patients. Will visual therapy remedy the cognitive and related motor disorders, resulting in a synchronized VEP.
Methods :
Fiftysix normal controls ranging in age from 13 to 67 year-old, fortyone mTBI patients ranging in age from 13 to 67 year-old, were tested with Diopsys NOVA Vision Testing System's VEP ad hoc module to measure their electrophysiological visual function's responsen to successively presented with 16x16, 32x32 and 64x64 checkerboard stimuli at a 15% Michelson contrast level. Twentyone mTBI patients received treatment and had VEPs obtained post treatment. The latencies of the normal controls were compared to the latiencies of the mTBI patients pre and post treatment. The Pearson's coefficient was calculated for the pre and post treatment population at the three spatial frequencies.
Results :
The VEP's P100 latency is an indicator of the neural impulse. Normal controls average P100 latiencies was 102.40ms (95%CI:99.96 to104.70),112.45ms (95%CI:110.34 to114.55) and 125.37ms (95% CI:123.03 to 127.71) for the successive spatial frequencies. This upward slope is interpreted as synchronization of the retina;s neural network. The mTBI patients showed a loss of synchronization. The VEP responses for the successive spatial frequencies were 119.11ms (95%CI:112.06 to126.16),116.88ms(95%CI:112.22 to 121.48) and 120.70ms (95%CI:117.52 to 123.88). Post treatment VEP latencies of successive stimulus are: 107.36ms (95%CI:102.83 to 111.90),114.45ms (95%CI:110.42 to 118.49) and 125.92ms (95%CI:120.34 to 131.51) indicating synchronization.The correlation between the pre and post treatment group at the three spatial frequencies was:16x16 (r=0.00, p=.9999) 32x32 (r=0.5788, 95%CI:0.207 to 0.804, p=.0048) and 64x64 (r=0.375, 95%CI: -0.694 to 0.0067, p=.094)
Conclusions :
VEPs can indicate normal function and dysfunction of retinal signals indicated by the slope produced from the measurements of successive spatial frequencies. This clinical tool can be helpful in response to mTBI.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.