Studies after studies, it is being demonstrated that functional MRI can be helpful in the identification of residual cognitive function in some patients with OSA (Obstructive Sleep Apnea). When there is concern about the accuracy of the diagnosis and the possibility that residual cognitive function has remained undetected., it is better to try fMRI. The future use of functional MRI will substantially increase our understanding of disorders of consciousness following severe brain injury. fMRI can be reported remotely or can we have a fMRI second opinion if the facility at radiologist end has the requisite software. This would save the huge costs of the Centre in charge.
Research OSA with fMRI
One of the researched studies concerning OSA (Obstructive Sleep Apnea) was done by Dr P.M. Macey and Dr K.E. Macey along with others. They had published their findings in ScienceDirect magazine. The study included a sample of 16 patients/subjects in whom artificially induced or produced similar expiratory loading pressures. The appropriate autonomic responses did not emerge in OSA cases. According to the study, "Reduced neural signals emerged in OSA cases within the frontal cortex, anterior cingulate, cerebellar dentate nucleus, dorsal pons, anterior insula, and lentiform nuclei. Signal increases in OSA over control subjects developed in the dorsal midbrain, hippocampus, quadrangular cerebellar lobule, ventral midbrain, and ventral pons. fMRI showed that Fastigial nuclei and the amygdala showed substantially increased variability in OSA subjects. The thalamus showed no change. OSA patients fMRI showed activities in multiple brain areas and unregulated cardiovascular responses to expiratory loading. This could be due to previously-demonstrated limbic, cerebellar, and motor area gray matter loss." Hence, fMRI was very helpful in the study to evaluate the subjects.
In another fMRI study by X. Zhang, L. Ma, S. Li, Y. Wang, L. Wang, published in Sleep Medicine, 2011 by Elsevier, it was revealed that patients with severe OSAS showed reduced frontal activation and more activity in the right aPFG compared to healthy subjects. In addition, both the oxygen desaturation duration and arousal index were associated with slower reaction times (RT) and greater reduction in the frontal activation in ROIs for OSAS patients during mismatch information processing. Other OSAS variables were not associated with changes in ROI response to either mismatch or match tasks. This study also made it possible to look at dynamic data due to fMRI niceties.
FMRI; Clear Winner
The advantages of fMRI are clear, and they outnumber the disadvantages. With fMRI, a deep assessment of patients with disorders of consciousness, especially in the case of OSA, is possible. However, it is quite subjective. More and more fMRI studies are making it clear that functional MRI can be a miracle in the identification of residual cognitive functions, improving the accuracy of diagnosis and detecting residual cognitive function that may have remained undetected. The future use of functional MRI will substantially increase our understanding of disorders of consciousness following severe brain injury.