Disorders of the anterior attentional-intentional system in patients with end stage renal disease: Evidence from reaction time studies.

Objective: Dialyzed patients with end-stage renal disease (ESRD) have been reported to have several neurobehavioral impairments that are often accompanied by structural and functional abnormalities of frontal-subcortical networks. Whereas the anterior attentional-intentional systems responsible for the allocation of attention and preparation for action (intention) are mediated by these frontal-subcortical networks, these functions have not been specifically investigated in this population.
Method: Twenty-three non-demented dialyzed patients with ESRD were compared with 25 matched controls on the performance on four reaction time (RT) subtests from the ROtman-Baycrest Battery to Investigate Attention (ROBBIA). These included measures of Simple, Choice, and Prepare RTs as well as a Concentrate task.
Results: In the Prepare RT task with a warning signal presented 1s before the onset of imperative stimulus, the patients' performance was not different than the controls; however, dialyzed patients became significantly slower than controls in the Prepare 3s warning condition as well as on all other RT measures. Nonetheless, both groups exhibited a gradual decrease in RT with increasing interstimulus intervals, with no group difference in the number and type of errors.
Conclusions: These results suggests, that while with external preparatory stimuli, the dialyzed ESRD patients may be able to acutely increase their arousal and enhance their allocation of selective attention or action-preparation, they appear not to be able to maintain this enhanced preparatory status. Whereas these results help to elucidate a potential source of disability in this patient population, future studies will need to examine if this deficit is primarily attentional, intentional or both (arousal), as well as explore possible treatments.
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