Ultra-Slow delta power in chronic fatigue syndrome
– Source: Psychiatry Research, Jul 6, 2012
By Olivier Le Bon, et al.
[Note: Delta brain waves are large low frequency waves (neuron oscillations) usually associated with the deepest stages of sleep or ‘slow-wave’ sleep; they begin to appear in stage 3 sleep but dominate by stage 4. Normally they stimulate the release of growth hormone  from the pituitary; they stimulate release of the hormone prolactin (which has more than 300 known effects including immune regulation and bodily water & salt balance); and they lead to a decrease in thyroid stimulating hormone activity.]
The role of sleep in patients diagnosed with chronic fatigue syndrome is not fully understood. Studies of polysomnographic and quantitative sleep electroencephalographic (EEG) measures have provided contradictory results, with few consistent findings in patients with Chronic Fatigue Syndrome (CFS).
For the most part, it appears that delta EEG activity may provide the best discrimination between patients and healthy controls.
A closer examination of delta activity in the very slow end of the frequency band is still to be considered in assessing sleep in CFS.
The present preliminary study compared absolute and relative spectral power in conventional EEG bands and ultra-slow delta (0.5-0.8Hz) between 10 young female patients with the CFS and healthy controls without psychopathology.
• In absolute measures, the ultra-slow delta power was lower in CFS, about one-fifth that of the control group.
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• Other frequency bands did not differ between groups.
• Relative ultra-slow delta power was lower in patients than in controls.
CFS is associated with lower ultra-slow (0.5-0.8Hz) delta power, underscoring the importance of looking beyond conventional EEG frequency bands.
From a neurophysiological standpoint, lower ultra-slow wave power may indicate:
• Abnormalities in the oscillations in membrane potential
• Or a failure in neural recruitment* in those with CFS.
*[‘Neural recruitment’ is defined as a tendency for a neural response to spread or increase with a prolonged stimulus.]
Source: Psychiatry Research, Jul 6, 2012 . PMID:22771174, by Le Bon O, Neu D, Berquin Y, Lanquart JP, Hoffmann R, Mairesse O, Armitage R. Brugmann University Hospital, Sleep Laboratory and Unit for Chronobiology and Hopital Erasme, Sleep Research Unit, Universite Libre de Bruxelles, Brussels, Belgium. [Email: email@example.com ]