Cerebral Perfusion Patterns Abnormal in CFS
Patients
WESTPORT, Jun 23 (Reuters Health) -
High-resolution single-photon emission tomography shows significant
similarities — and differences — between patients with chronic fatigue
syndrome (CFS) and those with major depression.
Dr. Klaus P. Ebmeier of Edinburgh University in the UK and associates
evaluated scans from 30 subjects with CFS in whom current psychiatric
illness was excluded, 12 subjects with a diagnosis of major depressive
episode, and 15 healthy control subjects. Subjects were matched for age,
gender, premorbid IQ and handedness.
As reported in the June issue of the British Journal of Psychiatry, uptake
of technetium-99m was greater in the right thalamus, the pallidum, and
putamen in subjects with CFS and those with depression compared with healthy
controls. However, the chronic fatigue syndrome patients exhibited increased
perfusion in the left thalamus. Decreased perfusion in the left prefrontal
cortex was found in patients with depression.
The researchers attribute the increased perfusion observed in chronic
fatigue syndrome and depression to "disturbances of motor function...and
effort perception," rather than to "low mood and inactivity," that are
characteristic of both disorders.
"Importantly for chronic fatigue syndrome, the lateral ventral nucleus of
the thalamus receives input from muscle afferents and the cerebellum that
provide critical information about motor state," the investigators write.
They explain that thalamic overactivity may be associated with higher levels
of vigilance required for previously automatic tasks.
The decreased prefrontal perfusion in the depressed patients compared with
those with CFS fits in with the fact that patients with depression have
similar motor but more profound cognitive deficits than patients with
chronic fatigue syndrome.
From these data the researchers conclude that biological disturbance in
chronic fatigue syndrome is not limited to those with comorbid depressive
symptoms. However, these changes are quantitative and currently are not
useful in the clinical diagnosis of chronic fatigue syndrome.
Br J Psychiatry 2000;176:550-556.
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