Are dexamethasone suppression test nonsuppression and thyroid dysfunction related to a family history of dementia in patients with major depression? An exploratory study.

OBJECTIVE: Recent data suggest that the low thyroid function syndrome in depression is nonspecific. They also suggest that depression may constitute a risk factor for the development of dementia, especially in atypical patients who have high rates of hypothalamo-pituitary-adrenal axis disorders. This study aimed to search for correlations among Dexamethasone Suppression Test (DST) cortisol levels, thyroid indices, and family history of dementia in patients with depression. METHODS: A sample of 30 patients, aged 21 to 60 years and suffering from major depression according to DSM-IV criteria, took part in the study. Three had a family history of dementia in first-degree relatives. We measured their serum levels of free T3, free T4, thyroid-stimulating hormone, thyroid binding inhibitory immunoglobulines, thyroglobulin antibodies, and thyroid microsomal antibodies (TMAs). We applied the 1-mg DST to all patients. The statistical analysis included 1-way multivariate analysis of covariance using t tests as the post hoc tests. RESULTS: Significantly higher levels of TMAs were found in patients with a family history of dementia, compared with those who did not have this family history. CONCLUSION: The results of this study suggest that a more pronounced autoimmune process may characterize depression patients with a family history of dementia.

Clinical and neuroimaging correlates of abnormal short-latency Somatosensory Evoked Potentials in elderly vascular dementia patients: A psychophysiological exploratory study.

BACKGROUND: Short Latency Somatosensory Evoked Potentials (SEPs) may serve to the testing of the somatosensory tract function, which is vulnerable and affected in vascular encephalopathy. The aim of the current study was to search for clinical and neuroimaging correlates of abnormal SEPs in vascular dementia (VD) patients. MATERIALS AND METHODS: The study included 14 VD patients, aged 72.93 PlusMinus; 4.73 years, and 10 controls aged 71.20 PlusMinus; 4.44 years. All subjects underwent a detailed clinical examination, blood and biochemical testing, brain MRI and were assessed with the MMSE. SEPs were recorded after stimulation from upper and lower limbs. The statistical Analysis included 1 and 2-way MANCOVAs and Factor analysis RESULTS: The N13 latency was significantly prolonged, the N19 amplitude was lower, the P27 amplitude was lower and the N11-P27 conduction time was prolonged in severely demented patients in comparison to controls. The N19 latency was prolonged in severely demented patients in comparison to both mildly demented and controls. The same was true for the N13-N19 conduction time, and for the P27 latency. Patients with subcortical lesions had all their latencies prolonged and lower P27 amplitude. DISCUSSION: The results of the current study suggest that there are significant differences between patients suffering from VD and healthy controls in SEPs, but these are detectable only when dementia is severe or there are lesions located in the subcortical regions. The results of the current study locate the abnormal SEPs in the white matter, and are in accord with the literature.