Hypoglycaemia in Clinical Diabetes

2 Symptoms of Hypoglycaemiaand Effects on MentalPerformance and EmotionsIan J. DearyINTRODUCTIONThis chapter describes the symptoms that are perceived during acute hypoglycaemia, andthe changes in mental functions and emotions that occur during this metabolic state.The most obvious benefit to a person of knowing about the symptoms of hypoglycaemiais the ability to recognise the onset of a hypoglycaemic episode as early as possible. This isof key importance in informing and educating people with diabetes. Moreover, if a personwith diabetes understands which mental functions are affected by hypoglycaemia he or shecan judge which activities may be most threatened in this state.SYMPTOMS OF HYPOGLYCAEMIAIdentifying the SymptomsThe physiological responses to hypoglycaemia are described in Chapter 1. The responseto hypoglycaemia results in physical symptoms, which raises several questions (McAulayet al., 2001b). Can we compile a comprehensive list of symptoms of hypoglycaemia? Whichare the more common symptoms of hypoglycaemia? Are there early warning symptoms ofhypoglycaemia? Do people differ in how quickly and accurately they detect or recognisehypoglycaemia? Do people differ in the set of symptoms of hypoglycaemia they experience?How can individuals distinguish the symptoms of hypoglycaemia from other bodily changes?The total symptom complexThe most basic question is: what symptoms do people report when they develophypoglycaemia?In humans the symptoms associated with hypoglycaemia were first recorded when insulinbecame available for the treatment of diabetes (Fletcher and Campbell, 1922). A list ofcharacteristic symptoms was described (Table 2.1). It was noted: that some symptomsHypoglycaemia in Clinical Diabetes, 2nd Edition.© 2007 John Wiley & Sons, LtdEdited by B.M. Frier and M. Fisher