Choice reaction time and adequacy of dialysis: a new application of an old method.
BACKGROUND
Choice Reaction Time (CRT) is the time it takes for a subject to accurately respond to a flashing panel of lights. The CRT has been used to assess the quality of dialysis in hemodialysis patients and to assess the neurological impairments in patients with Parkinson's disease.


METHODS
Three groups of end-stage renal disease (ESRD) patients on three different renal replacement therapies were tested using CRT: intermittent peritoneal dialysis (IPD, n = 11), thrice weekly hemodialysis (HD, n = 22), and well-functioning kidney transplant (Tx, n = 6). A group of volunteers with normal renal function (NL, n = 12) was also tested.


RESULTS
The CRT was significantly longer in IPD patients (618 +/- 89 ms) than observed in the other three groups (p < 0.0001). CRT in HD patients was 461 +/- 50 ms, which was significantly longer than in Tx patients (396 +/- 25 ms, p = 0.05). However, the CRT in the Tx patients was no different from the NL (382 +/- 22, p = 0.32). There was a strong negative correlation between CRT and weekly creatinine clearance in the IPD group (r =- .96) and between the dialysis index and CRT in HD (r =- 0.79).


CONCLUSIONS
CRT may be a useful tool in assessing the adequacy of dialysis.
Ahmad
Suhail
S
University of Washington, Seattle, Washington, U.S.A. sahmad@u.washington.edu