The Cognitive Impairment Caused By Primary Hypothyriodism: Clinical Profiles And A Treatment Study

Background:Primary hypothyroidism is one of the reversible dementia diseases.the neurocognitive dysfunction and reversals of cognitive impairment after pharmacotherapies in adults with hypothyroidism are rarely known.most of the published reports on neuropsychological functioning in adults are based on the assessment of only limited aspects of cognitive domains,and subjects of these reports are small.these observations raise the issues on domains of cognitive impairment and outcome of pharmacological intervention.Objectives:To investigate the neuropsychological characteristics of primary hypothyroidismand reversibility after pharmacological intervention. (1) to determine whether theclinical features are different between the young and the aged patient withhypothyroidism. (2) to evaluate objectively changes in cognitive functionassociated with hypothyroidism of varying severity of thyroid hormone. (3) toevaluate whether the cognitive impairment domains are different between theyoung and aged . (4) to determine whether these changes are reversible when aeuthyroid state has been attained after treatment with thyroid hormone .To investigate the cognitive impairment in 5 diseases related with reversibledementia.Methods:A cross-section study: comparision of 13 clinical signs between elderly patients(≥55 years of age) and younger patients (<55 years of age ), 20 elderly patientsand 45 younger patients were included in the study.We enrolled 60 primary hypothyroid patients (average 43.6±12.8yr ), of which were 20 patients with subclinical hypothyroidism(average 43.7±13.3yr), 18 patients with moderate hypothyroidism ,22 patients with severe hypothyroidism,and 60 euthyroid controls with the same age ,gender and education as the patients screened for good general health. Follow-up study: 20 patients were retested when euthyroid ,6 months after onset of thyroid replacement therapy . and their controls with the same age ,gender education as the patients are also retested after six months. Thyroid-stimulating hormone, free thyroxine, free tri-iodothyronine were measured. Standard neuropsychological examination were performed in all participates including mini-mental state examination, word list learning, recall and recognize, clock drawing test, cube drawing ,figure copy and recall, picture recall, verbal fluency (animal and fruit), trail making A and B, block design, digital span, digital-symbol from WAIS-RC.Retrospective study: 10-year cases related with reversible dementia in 301 hospital.Results:(1)Hypomnesia in primary hopothyroidism is 63%.Syncope(20%),swoolen (35%),snoring(35%), palpitation(30%) were more frequent in the eldly patients, while weight gain(28.8%),goiter(75.7%) were more frequent in the younger. (2)Subclinical hypothyroid patients compared with the same age, gender,and education controls showed a significant difference in word list learning ,figure recall ,picture recall,verbal fluency,digit span,trail making A and B (p<0.05).Moderate hypothyroid patients showed difference in block design, clock drawing test besides these which had shown in subclinical hypothyroidism(p<0.05).The severe hypothyroid patients showed neuropsychological dysfunction in all 11 tests (p<0.05)o(3)The elderly patients showed significantly lower scores on trail A test (100.2 ± 57.8 vs. 61.5±29.9 p=0.01) ,the 3rd times word list learning (6.1 ± 1.2 vs. 7.2...