Modeling the effects of hypoglycemia on a two-choice task in adult humans.

OBJECTIVE: Previous research has demonstrated that hypoglycemia causes reaction times to be slower and more variable. Reaction time tests, however, use multiple cognitive and noncognitive processes. This study is the first to use a validated sequential sampling model (diffusion model) applied to results obtained from a simple 2-choice task in adult humans to assess the effects of hypoglycemia on the basic parameters of decision making. METHOD: Fourteen adult volunteers were tested on a numerosity discrimination task with and without reduced blood glucose concentrations. The results were analyzed with a model that dissects the components of processing that underlie decisions: the quality of the information on which a decision is based (drift rate), the critical amount of evidence that must be accumulated before a decision is made (boundary separation), and the time taken by nondecision processes. RESULTS: Hypoglycemia resulted in a reduction of mean drift rate from 0.290 to 0.211, t(13) = 4.10, p < .05. No effect of experimental state was observed on the amount of evidence required to make a decision or peripheral and motor processes. CONCLUSION: This study locates the precise processing deficit associated with hypoglycemia and provides further understanding of the precise cognitive effect of hypoglycemia. Further research into the amelioration of these effects is required.