Diabetes Care, Vol 18, Issue 5 681-685, Copyright © 1995 by American Diabetes Association
Short-term and long-term memory in elderly patients with NIDDM
EL Helkala, L Niskanen, H Viinamaki, J Partanen and M Uusitupa
Department of Neurology, Kuopio University Hospital, Finland.
OBJECTIVE--To determine cognitive and memory dysfunction associated with
non-insulin-dependent diabetes mellitus (NIDDM) and its relationship with
depression, metabolic control, and serum lipids. RESEARCH DESIGN AND
METHODS--We studied a well-characterized group of 20 elderly patients with
NIDDM and 22 control subjects with normal glucose tolerance recruited from
a larger population-based sample. In addition to clinical and laboratory
examinations, self-rating questionnaires that assess minor psychiatric
disorder (General Health Questionnaire) and depression (Zung scale) were
completed by patients and control subjects. Memory was examined with digit
and block-span tests, word-list learning, Heaton Visual Memory Test, and
Moss Visual Span Test. Executive functions were examined by Trail-Making A
and B test and by Verbal and Category Fluency Tests. Visuoconstructive
reasoning was examined with the block 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 recalled no fewer words than the control subjects,
but the process of of learning seemed to be different in the two groups.
The recognition of the learned words was not impaired. Elevated serum total
and very-low-density lipoprotein triglyceride levels, measured either
before examinations or 5 or 10 years earlier, were associated with effects
on retrieval from semantic memory in NIDDM patients. CONCLUSIONS--The NIDDM
patients had impaired control of their learning processes. Elevated serum
triglyceride levels may be related to control of mental processing in
diabetic patients.