No Effects of Acute Psychosocial Stress on Working Memory in Older People With Type 2 Diabetes

Abstract

Type 2 diabetes (T2D) has been considered a public health threat due to its growing prevalence, particularly in the older population. It is important to know the effects of psychosocial stress and its potential consequences for some basic cognitive processes that are important in daily life. Currently, there is very little information about how people with T2D face acute psychosocial stressors, and even less about how their response affects working memory (WM), which is essential for their functionality and independence. Our aim was to characterize the response to an acute laboratory psychosocial stressor and its effects on WM in older people with T2D. Fifty participants with T2D from 52 to 77 years old were randomly assigned to a stress (12 men and 12 women) or control (12 men and 14 women) condition. Mood and physiological (cortisol, C, and salivary alpha-amylase, sAA) responses to tasks were measured. In addition, participants completed a WM test before and after the stress or control task. Our results showed that the TSST elicited higher negative affect and greater C and sAA responses than the control task. No significant differences in WM were observed depending on the exposure to stress or the control task. Finally, participants who showed higher C and sAA responses to the stressor had lower WM performance. Our results indicate that medically treated older adults with T2D show clear, typical mood and physiological responses to an acute psychosocial stressor. Finally, the lack of acute psychosocial stress effects on WM suggests that it could be related to aging and not to this disease, at least when T2D is adequately treated.

Keywords: alpha-amylase; cortisol; older adults; psychosocial stress; type 2 diabetes; working memory.

FIGURE 1

Timeline of the TSST (S) and control (C) conditions. Salivary cortisol samples = 1^o̱ C, 2^o̱ 3^o̱ C, 4^o̱ C, 5^o̱ C, 6^o̱ C, 7^o̱ C Salivary alpha-amylase samples = 1^o̱α, 2^o̱α 3^o̱α, 4^o̱α, 5^o̱α, 6^o̱α, 7^o̱α. Time of collection of saliva samples (−15, +5, +10, +25, +35j +45, +50). TSST, trier social stress test; PANAS, positive and negative affect; LNS, letter-number sequencing; VAS, situational appraisal.

FIGURE 2

Means of salivary corliaol concentrations for stress and control conditions. Error bars represent standard error of means (^∗p < 0.05).

FIGURE 3

Means of salivary alpha-amylase concentrations for stress and control conditions. Error bars represent standard error of means (^∗p = 0.002).

FIGURE 4

Performance on Letter-Number sequencing (LNS) tor stress and control conditions before and after the task.