BACKGROUND: The diagnosis of "subclinical uremic encephalopathy" may need the administration of sensitive tests. PURPOSE: To test the hypotheses that (1) patients on chronic hemodialysis (CHD) fare worse than normal controls on a brief performance battery, (2) one extra-day of uremia further jeopardizes the neuropsychological performance of CHD patients, and (3) uremia impairs improvement on a second testing session. METHOD: The cognitive and motor agility of 28 patients on CHD were assessed with the Trails A and B, Digit Symbol, and Stroop tests. RESULTS: (1a) cognitive and psychomotor performance were slowed in patients, (2a) one extra-day of uremia impaired performance further on Trail Making B, and (3a) CHD patients had a decreased ability to learn novel procedures even in the short-term. CONCLUSION: CHD patients may present with a "subclinical encephalopathy" whose detection may require the administration of sensible tests. Mental and motor agility, and the ability to learn new routines are impaired in at least some CHD patients with a normal global cognitive state.
uremia; neuropsychology; chronic hemodyalisis; subclinical encephalopathy
