Cumulative cognitive impairment following recurrent severe hypoglycaemia in adult patients with insulin-treated diabetes mellitus

Abstract

To examine the hypothesis that episodes of severe hypoglycaemia may cause cumulative cognitive impairment. 100 Type 1 (insulin-dependent) diabetic patients were examined. Their age range was 25-52 years, and the onset of diabetes had occurred after the age of 19 years. Patients with evidence of organic brain disease, including cerebrovascular disease, were excluded. A questionnaire was used to assess the number, frequency and severity of hypoglycaemic episodes experienced during treatment with insulin and the accuracy of this retrospective information was verified from general practice and hospital case-notes. A detailed neuropsychological assessment was undertaken, including tests of pre-morbid and present IQ (Wechsler-Revised), memory and information-processing speed. Significant correlations were observed between the frequency of severe hypoglycaemia and the magnitude of intellectual decline, Performance IQ, inspection time and reaction time (patients with the more frequent hypoglycaemia had poorer performance). Two sub-groups of patients were identified on the basis of their experience of severe hypoglycaemia, and were balanced for pre-morbid IQ, age and duration of diabetes. One sub-group (n = 23) had never experienced severe hypoglycaemia (Group A), whilst the other sub-group (n = 24) had suffered at least five episodes of severe hypoglycaemia (Group B). Group B had greater intellectual impairment than Group A, and Group B also had a significantly slower mean reaction time and higher reaction time variance when compared with Group A.

Models and Paradigms in Personality and Intelligence Research

“…Diabetic patients perform worse than normal subjects on measures of Gf--i.e., on complex abstract reasoning tasks, but do not differ from normal controls on Gc. While Langan, Deary, Hepburn, and Frier (1991) reported a significant correlation between frequency of severe hypoglycemia and performance IQ, this relationship did not emerge with verbal fluency and auditory learning scores. Also, Deary (1992) demonstrated the critical role of frequent severe hypoglycemia in development of cognitive deficit.…”

Evaluación neuropsicológica de la diabetes mellitus tipo 1 en la infancia

“…Por lo tanto, en nuestra investigación estas diferencias se pueden achacar a otros aspectos de la enfermedad como el nivel de control metabólico. Langan et al (1991) apreciaron que las personas diabéticas con un mayor número de episodios de hipoglucemia obtenían puntuaciones más bajas en pruebas neuropsicológicas como consecuencia de la intensidad y frecuencia de las hipoglucemias sufridas. Nosotros no pudimos comprobar estas conclusiones ya que nuestra muestra no había tenido el número suficiente de hipoglucemias para poder llegar a esta conclusión.…”

Managing type I diabetes in pregnancy: how near normal is necessary?

“…19,20 Recurrent hypoglycemia may have cumulative adverse effects on cognitive function. 21 Counterregulatory hormonal responses to hypoglycemia change during pregnancy. Both normoglycemic women and those who have type I diabetes have diminished peak epinephrine and glucagon responses to induced hypoglycemia during pregnancy.…”