Effects of acute hypoglycaemia on auditory information processing in adults with Type I diabetes

Abstract

Aims/hypothesis. Acute hypoglycaemia in humans causes general impairment of cognitive function, but information about its effects on more specific cognitive processes is limited. Methods. Basic aspects of auditory function were studied in 15 adults with uncomplicated Type I (insulin-dependent) diabetes mellitus. Two separate hyper insulinaemic glucose clamp procedures were done on different study days, in a counterbalanced fashion, either maintaining euglycaemia (blood glucose 5.0 mmol·l -1 ) or inducing hypoglycaemia (blood glucose 2.6 mmol·l -1 ). During each study, the subjects performed a battery of auditory and cognitive function tasks. Results. Hypoglycaemia caused deterioration in mental efficiency as assessed by Digit Symbol (p<0.001) and Trail Making B (p=0.004) tasks. Acute hypoglycaemia also caused deterioration in one of three measures of simple auditory processing (single-tone loudness, p=0.001) and in auditory temporal processing (p=0.007). The amplitude and latency of auditory N100, P200 and P300 event-related potentials were not affected, but the amplitude of the N240 potential was reduced during acute hypoglycaemia. Conclusion/interpretation. Our findings are consistent with other recognised disruptive effects of acute hypoglycaemia on sensory information processing in nondiabetic and diabetic adults, including adverse effects on auditory information processing in non-diabetic subjects. These derangements have implications for the everyday activities of people with Type I diabetes who are frequently exposed to acute hypoglycaemia. [Diabetologia (2003) 46:97-105] Keywords Hypoglycaemia, cognition, auditory information processing, auditory event-related potentials, Type I diabetes mellitus. . The pattern of impairment of these tests allows a general interpretation of the nature of cognitive dysfunction during hypoglycaemia, but provides little information about the impact of hypoglycaemia on specific brain processes such as basic sensory information processing.Two previous studies in our laboratory examined the ability of the brain to process visual information during acute hypoglycaemia. In one study [2] acute hypoglycaemia did not affect visual acuity or stereoscopic vision in non-diabetic subjects, but caused disPeople with Type I (insulin-dependent) diabetes mellitus are frequently exposed to episodes of acute hypoglycaemia. In experimental studies, a wide range of mental functions are impaired when arterialised blood

Short-Term, Delayed, and Working Memory Are Impaired During Hypoglycemia in Individuals With Type 1 Diabetes

“…In sensory memory, representations of the physical features of a stimulus are stored for a very brief time (Յ1 s), and it is difficult to distinguish from the process of perception. The deleterious effect of hypoglycemia on this memory system has been demonstrated in previous studies conducted in our center (11)(12)(13)(14). It seems that the principal function of sensory memory is to retain information for a period of time sufficient to allow its transfer to short-term memory.…”

Glucoregulation has Greater Impact on Cognitive Performance than Macro-vascular Disease in Men with type 2 Diabetes: Data from the Caerphilly Study

“…Laboratory evidence, however, suggests a more complicated picture, with the cognitive effects of hypoglycemia [24][25][26][27] being distinct from those of hyperglycemia [28][29][30]. These studies suggest that that associations of diabetes with cognitive performance may be due directly to glucoregulation, rather than the chronic effects of hyperglycemia on vascular and neurological pathology.…”

Enhanced Dopamine D1 and D2 Receptor Gene Expression in the Hippocampus of Hypoglycaemic and Diabetic Rats

“…Studies suggest that acute or chronic hypoglycaemia leads to neurological dysfunction and injury. Progressive hypoglycaemia leads to cognitive and memory impairment (McCrimmon et al 1997;Ewing et al 1998;Strachan et al 2004). Children and adults exposed to hypoglycaemia can develop long-term impairment of cognitive function (Karp 1989;Hawdon 1999;Vannucci and Vannucci 2001) and are at risk of epilepsy (Kaufman 1998).…”