Characteristics influencing expected cognitive performance during hypoglycaemia in type 2 diabetes

Psychoneuroendocrinology. 2019 Dec:110:104431. doi: 10.1016/j.psyneuen.2019.104431. Epub 2019 Sep 4.


Background: Acute hypoglycaemia is associated with cognitive impairment in patients with type 2 diabetes. However, there is limited understanding of the relationship between patients' expected cognitive difficulties and their objectively-measured deficits during non-severe hypoglycaemia.

Objective: This report investigates demographic and clinical factors associated with the discrepancy between expected (i.e., self-evaluated) and measurable (i.e., neuropsychological) cognitive functions in patients with type 2 diabetes during acute non-severe hypoglycaemia.

Methods: We performed an analysis of factors associated with the relationship between expected and measurable cognitive performance for data collected from a cohort of patients with type 2 diabetes (N = 25). Patients attended two experimental visits during which we performed hyper-insulinaemic glucose clamping; (i) non-severe hypoglycaemic clamp (plasma glucose (PG): 3.1 ± 0.3 mmol/L) and (ii) normoglycaemic clamp (PG: 5.8 ± 0.3 mmol/L), as part of a double-blinded cross-over study. During hypoglycaemia, patients' expected cognitive performance was assessed with a visual analogue scale after which objective cognitive functions were assessed with a neuropsychological test battery. We computed a global 'cognitive discrepancy' composite variable with score values on a scale between -10 and +10 using a novel statistical formula that creates a discrepancy score between subjective and objective cognition. Positive values reflect more expected than objectively-measured difficulties, while negative values reflect disproportionately more objectively-measured than expected cognitive difficulties. We used paired samples t-tests to compare degree of cognitive discrepancy between conditions of hypo- and normoglycaemia, while multiple regression analysis was performed to identify factors associated with the degree and direction of the cognitive discrepancy. The significance level for the analyses was p ≤ 0.05 (two-tailed).

Results: Patients generally underestimated their cognitive abilities (M = 1.6, SD = 3.3) during hypoglycaemia compared to normoglycaemia (M = -1.0, SD = 3.5) (p = 0.2), t(23) = 2.9, p < 0.01. Underestimation of cognitive capacity during hypoglycaemia was more pronounced for patients with younger age (β = 0.5, p = 0.02), higher verbal IQ (β = 0.5, p = 0.03), and more hypoglycaemia-related shakiness (β = 0.4, p = 0.03).

Limitations: The modest sample size limits the generalizability of the findings.

Conclusions: Patients with type 2 diabetes underestimated their cognitive abilities during non-severe hypoglycaemic states, especially those with younger age, higher IQ, and more hypoglycaemia-related shakiness. These patients may thus have excessive preoccupations with their cognitive difficulties in relation to cognitively challenging daily life situations.

Keywords: Cognition; Diabetes; Hypoglycaemia.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Blood Glucose / drug effects
  • Blood Glucose / metabolism
  • Cognition / drug effects
  • Cognitive Dysfunction / chemically induced
  • Cognitive Dysfunction / epidemiology
  • Cognitive Dysfunction / etiology*
  • Cross-Over Studies
  • Diabetes Mellitus, Type 2 / complications*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / psychology
  • Double-Blind Method
  • Female
  • Humans
  • Hypoglycemia / chemically induced
  • Hypoglycemia / complications*
  • Hypoglycemia / epidemiology
  • Hypoglycemic Agents / adverse effects
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Risk Factors
  • Severity of Illness Index


  • Blood Glucose
  • Hypoglycemic Agents