Effect of age and glucoregulation on cognitive performance.
Non-insulin dependent diabetes mellitus (NIDDM) has been associated with a number of physiological consequences including neuropathy, retinopathy and incidence of vascular disease. Recently, several authors reviewed studies that suggested that NIDDM is associated with cognitive impairments leading to a higher incidence of dementia. In the present experiment, we measured cognitive function in 57 healthy male and female non-diabetic older participants who ranged in age from 55 to 84. Various biological measures were obtained including a glucose tolerance test during which glucose and insulin were measured. Participants were separated into better and poorer glucoregulatory groups on the basis of their blood glucose levels during the tolerance test. Participants were evaluated twice, once after drinking a saccharin solution and on another occasion after drinking a glucose solution (50 g). Older participants (72 years and over) with poorer glucoregulation had the worse performance in tests evaluating working memory, verbal declarative memory and executive functions. Glucose administration appeared to only attenuate the decrements observed in the saccharin condition in the older participants for some of the tests. These results suggest that cognitive functions may be impaired before glucoregulatory impairment reaches levels consistent with a type II diabetes diagnosis.
Messier
Claude
C
School of Psychology, University of Ottawa, 145 Jean-Jacques Lussier Room 352, Ont., K1N 6N5, Ottawa, Canada
Tsiakas
Maria
M
Gagnon
Michèle
M
Desrochers
Alain
A
Awad
Nesrine
N
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001786:Blood Glucose; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008568:Memory / Q000502:physiology*; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D013223:Statistics as Topic; D014706:Verbal Learning / Q000502:physiology*
D001786:Blood Glucose; D007328:Insulin; D005947:Glucose