Background
Elevated endogenous levels of corticosteroids cause neural dysfunction and loss, especially
within the hippocampus, as well as cognitive impairment in hippocampus-mediated tasks.
Because Cushing’s syndrome patients suffer from hypercortisolism, they represent a
unique opportunity to study the impact of elevated glucocorticoids on cognitive functions.
The aim of this study was to examine the performance of Cushing’s syndrome patients
on trace eyeblink conditioning, a cross-species, hippocampal-mediated test of learning
and memory.
Methods
Eleven Cushing’s syndrome patients and 11 healthy control subjects participated in
an eyeblink trace conditioning test (1000-msec trace) and a task of declarative memory
for words. Salivary cortisol was collected in both the patients and the control subjects,
and urinary free cortisol was collected in the patients only.
Results
The patients exhibited fewer conditional responses and remembered fewer words, compared
with the control subjects. Cortisol levels correlated with immediate and delayed declarative
memory only. Conditional response correlated with delayed recall after controlling
for the magnitude of unconditional response.
Conclusions
The integrity of the hippocampus seems to be compromised in Cushing’s syndrome patients.
Trace eyeblink conditioning might be useful both as a clinical tool to examine changes
in hippocampus function in Cushing’s disease patients and as a translational tool
of research on the impact of chronic exposure of glucocorticoids.
Key words
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Article info
Publication history
Accepted:
September 4,
2004
Received in revised form:
August 23,
2004
Received:
April 21,
2004
Identification
Copyright
© 2004 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
