Preliminary study of the relationship between thyroid status and cognitive and neuropsychiatric functioning in euthyroid patients with Alzheimer dementia.
OBJECTIVE
To investigate whether variations within normal ranges of thyroid functioning are related to cognitive and neuropsychiatric functioning in Alzheimer disease (AD).


BACKGROUND
Mild alterations of thyroid hormone levels, even in the normal range, are associated with changes in mood and cognitive functioning in older, nondemented adults, and lower concentrations of thyroid hormones have been shown to be associated with an increased risk for cognitive decline. Less is known about the relationship between thyroid hormone levels and cognitive and neuropsychiatric dysfunction in AD.


METHODS
Twenty-eight euthyroid patients with AD on donepezil underwent evaluation of thyroid status, including measures of thyroid-stimulating hormone (TSH) and free thyroxine (FT4), and cognitive and neuropsychiatric assessment with the Alzheimer's Disease Assessment Scale, Neuropsychiatric Inventory, and Visual Analog Mood Scales.


RESULTS
Correlational analyses indicated statistically significant associations between FT4 concentrations and self-reported feelings of fear and fatigue. Fear and fatigue were negatively correlated with FT4. There were no significant relationships between thyroid hormones and cognition and other depressive and anxiety symptoms.


CONCLUSIONS
Results of this preliminary study support a relationship between thyroid status and neuropsychiatric symptoms in euthyroid individuals with AD, with lower concentrations of FT4 associated with fear and fatigue.
Stern
Robert A
RA
Department of Neurology, Boston University School of Medicine, Robinson Suite 7800, 715 Albany Street, Boston, MA 02118, USA. bobstern@bu.edu
Davis
Jennifer D
JD
Rogers
Brooke L
BL
Smith
Kristin E R
KE
Harrington
Colin J
CJ
Ott
Brian R
BR
Jackson
Ivor M D
IM
Prange
Arthur J
AJ
D000342:Affective Symptoms / Q000097:blood* / Q000150:complications; D000368:Aged; D000544:Alzheimer Disease / Q000097:blood* / Q000150:complications / Q000188:drug therapy / Q000523:psychology*; D003072:Cognition Disorders / Q000097:blood* / Q000150:complications; D003430:Cross-Sectional Studies; D000077265:Donepezil; D005260:Female; D006801:Humans; D007189:Indans / Q000627:therapeutic use; D008297:Male; D009483:Neuropsychological Tests; D018697:Nootropic Agents / Q000627:therapeutic use; D010880:Piperidines / Q000627:therapeutic use; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood*
D007189:Indans; D018697:Nootropic Agents; D010880:Piperidines; D000077265:Donepezil; D013972:Thyrotropin; D013974:Thyroxine