This paper describes a method used to assess cognitive dysfunction (and hence neurotoxicity) in individual CAPD patients. An “impairment index” ranging from 0.0 (no impairment) to 1.0 (severe impairment), was calculated on the basis of a patient's performance on eight short psychometric tests. Findings suggested that the index is sensitive to organic changes in renal patients and that it is not strongly influenced by emotional or psychosocial factors. Some distinct subgroups of patients have been identified according to the degree of initial (pre-treatment) dysfunction; one of these subgroups appears to have a poor prognosis.
