Cognitive deficits associated with impaired awareness of hypoglycaemia in type 1 diabetes

Abstract

Aims/hypothesisThe aim of this study was to compare cognitive function in adults with type 1 diabetes who have impaired awareness of hypoglycaemia with those who have normal awareness of hypoglycaemia. A putative association was sought between cognitive test scores and a history of severe hypoglycaemia.MethodsA total of 68 adults with type 1 diabetes were included: 33 had impaired and 35 had normal awareness of hypoglycaemia, as confirmed by formal testing. The groups were matched for age, sex and diabetes duration. Cognitive tests of verbal memory, object-location memory, pattern separation, executive function, working memory and processing speed were administered.ResultsParticipants with impaired awareness of hypoglycaemia scored significantly lower on the verbal and object-location memory tests and on the pattern separation test (Cohen’s d −0.86 to −0.55 [95% CI −1.39, −0.05]). Participants with impaired awareness of hypoglycaemia had reduced planning ability task scores, although the difference was not statistically significant (Cohen’s d 0.57 [95% CI 0, 1.14]). Frequency of exposure to severe hypoglycaemia correlated with the number of cognitive tests that had not been performed according to instructions.Conclusions/interpretationImpaired awareness of hypoglycaemia was associated with diminished learning, memory and pattern separation. These cognitive tasks all depend on the hippocampus, which is vulnerable to neuroglycopenia. The findings suggest that hypoglycaemia contributes to the observed correlation between impaired awareness of hypoglycaemia and impaired cognition.Electronic supplementary materialThe online version of this article (doi:10.1007/s00125-017-4233-3) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

The impact of type 1 diabetes on neural activity serving attention

“…These recurrent episodes appear to lead to impairment in tracking and rectifying dysglycemia, thereby further impairing neural mechanisms in the process. Previous studies examining cognitive deficits and type 1 diabetes have identified a self‐perpetuating loop of disease mismanagement and increased cognitive decline (Grober et al, ; Hansen et al, ), which may at least partially explain the relationship between attention‐related neural dysfunction and disease duration apparent in the current study. With this progressive inability to manage the condition (i.e., maintain normoglycemia) leading to more rapid cognitive dysfunction, it is imperative that patients manage their glycemic levels carefully from the point of diagnosis to prevent detrimental long‐term outcomes.…”

“…Considering the body of literature examining cognitive impairment in patients with type 1 diabetes, deficits in attentional processes may have a unique impact on daily care behaviors and long‐term disease management. The impact of chronic hypoglycemia in insulin‐treated type 1 diabetes is well‐known throughout the literature (Cryer, , ; Grober et al, ; Hansen et al, ; Rooijackers et al, ; Seaquist et al, ), with these patients experiencing two hypoglycemic episodes on average weekly and an annual incidence of severe hypoglycemia requiring third‐party intervention of 1.0 to 1.7 episodes per patient (Frier, ; McCrimmon & Sherwin, ). These recurrent episodes appear to lead to impairment in tracking and rectifying dysglycemia, thereby further impairing neural mechanisms in the process.…”

“…Importantly, deficits in these domains have been specifically linked to measures of disease status including glycemic control and disease duration (Desrocher & Rovet, 2004;Tonoli et al, 2014). Such cognitive deficits have been shown to induce a circular pattern of dysfunction, whereby chronic dysglycemia leads to specific cognitive deficits, which in turn lead to impaired ability to monitor and maintain adequate blood sugar levels, and thereby further cognitive decline (Grober, Hall, Hahn, & Lipton, 2011;Hansen et al, 2017).…”

Altered Brain Dynamics in Patients With Type 1 Diabetes During Working Memory Processing

“…Unawareness of hypoglycemia, another long-term factor, has also been shown to induce further cognitive impairment. This hypothesis posits that as cognitive deficits arise, they affect the patient's ability to control glycemic levels, altering the awareness of the glycemic state and leaving the dysglycemia untreated, which ultimately leads to further cognitive decline (38,39). This cyclical decline increases the likelihood of devastating cognitive outcomes, such as mild Figure 5-Time series of parieto-occipital differences during maintenance.…”

Impaired hypoglycemia awareness in diabetes: epidemiology, mechanisms and therapeutic approaches

“…Данная взаимосвязь может определяться гипогликемией -общим фактором риска этих состояний. У пациентов с НРГ выявлено снижение способности к запоминанию и распознаванию образов [41]. Данные мозговые функции в значительной степени зависят от гиппокампа -структуры, очень чувствительной к нейрогликопении.…”