The relationship between intellectual impairment and thyroid deficiency is far from being completely elucidated. Recent literature on the subject is not voluminous.* One may expect that many questions will continue to remain unanswered until the physiology and biochemistry of thyroid function and failure are more perfectly understood. Current limitations notwithstanding, one may also expect the evidence collected from a large, randomly selected sample of hypothyroid patients to shed some light on the relationship between cognitional dysfunction and thyroid dysfunction. For this reason, I have, during the past four years, kept a group of patients with a history of hypothyroidism under psychologic study and have given an intelligence test to each of 70 such patients.
Method of Investigation
For the 20 years between 1935 and 1955, the files of the pediatric-endocrine clinic of the Harriet Lane Home record 149 cases of hypothyroidism. A few of these patients are now dead.