SHORT-TERM AND LONG-TERM-MEMORY IN ELDERLY PATIENTS WITH NIDDM

OBJECTIVE- To determine cognitive and memory dysfunction associated wi th non-insulin-dependent diabetes mellitus (NIDDM) and its relationshi p with depression, metabolic control, and serum lipids. RESEARCH DESIG N AND METHODS- We studied a well-characterized group of 20 elderly pat ients with NIDDM and 22 control subjects with normal glucose tolerance recruited from a larger population-based sample. In addition to clini cal and laboratory examinations, self-rating questionnaires that asses s minor psychiatric disorder (General Health Questionnaire) and depres sion (Zung scale) were completed by patients and control subjects. Mem ory was examined with digit and block-span tests, word-list learning, Heaton Visual Memory Test, and Moss Visual Span Test. Executive functi ons were examined by Trail-Making A and B test and by Verbal and Categ ory Fluency Tests. Visuoconstructive reasoning was examined with the b lock design subtest of the Wechsler Adult Intelligence Scale. RESULTS- The NIDDM patients showed preserved memory span, but poor performance in learning tasks compared with control subjects. The patients recall ed no fewer words than the control subjects, but the process of learni ng seemed to be different in the two groups. The recognition of the le arned words was not impaired. Elevated serum total and very-low-densit y lipoprotein triglyceride levels, measured either before examinations or 5 or 10 years earlier, were associated with effects on retrieval f rom semantic memory in NIDDM patients. CONCLUSIONS- The NIDDM patients had impaired control of their learning processes. Elevated serum trig lyceride levels may be related to control of mental processing in diab etic patients.