This study assessed the neurobehavioral status of adolescents with a long history of insulin-dependent diabetes mellitus. A comprehensive battery of tests was administered to 40 diabetic outpatients, 12-18 years of age, and to 40 demographically similar nondiabetic subjects. Results showed that diabetic patients performed within normal limits on all tests, though significant between-groups differences did appear on measures of verbal intelligence, visuomotor coordination, and critical flicker threshold. Although it could be argued that these results are indicative of structural brain damage, we discuss the possibility that the differences observed may be a function of transient metabolic abnormalities at the time of testing or, alternately, may be a reflection of the behavioral changes associated with having a life-threatening illness.

No abstract

The Halstead-Reitan test battery offers considerable promise as a standardized research and clinical technique for studying behavioral deficits associated with brain damage. With the goals of cross-validation and of providing usable normative data from a population in a different geographic setting, the tests were administered to 50 brain-damaged and SO control Ss. The brain-damaged patients performed more poorly than the controls (p<.001) on all but 1 test. The general level of performance was lower than that previously reported. Overall performance of the control Ss was significantly related to age and educational level, with correlations of -.57 and .56, respectively. Use of Halstead's Impairment Index resulted in a 73% correct classification of both groups using a cutoff score of .7. Scores were transformed to allow intra-and interindividual comparisons of level of performance. A modified index resulted in 79% correct classification.

A comprehensive battery of neuropsychological tests was administered to 125 adolescents with a history of insulin-dependent diabetes, and to 83 demographically similar nondiabetic control subjects. To test the hypothesis that developing this disease early in life greatly increases the risk of manifesting significant cognitive impairments, diabetic subjects were assigned to an "early-onset" (diagnosis before age 5 years) or a "lateronset" subgroup. Results showed that subjects with early onset of diabetes performed more poorly than either subjects with later onset of diabetes or nondiabetic control subjects on virtually all tests, including measures of intelligence, school achievement, visuospatial ability, memory, motor speed, and eye-hand coordination. Moreover, multiple regression analyses demonstrated that the age at onset and the duration of diabetes seem to affect neuropsychological functioning in very different ways. The duration of the disease best predicted performance on those tests requiring highly overlearned, primarily verbal, skills whereas the age at onset best predicted scores on tests requiring the ability to process relatively unfamiliar, typically nonverbal, information in novel ways. Although the etiology of these deficits remains unclear, there is a possibility that they are secondary to mild brain damage that develops as a consequence of multiple episodes of serious hypoglycemia early in life.