Treatment effects on brain activity during a working memory task in Obstructive Sleep Apnea

Aloia, M.S., Arnedt, J.T., Jerskey, B.A., Millman, R.P., Sweet, L.H., & Zimmerman, M. (2009).

Treatment effects on brain activity during a working memory task in Obstructive Sleep

Apnea. Journal of Sleep Research, 18, 404-410. doi: 10.1111/j.1365-2869.2009.00755.x

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Chapter 13 discusses sleep, sleep disorders, and the effects of those disorders on the brain. Obstructive Sleep Apnea (OSA) is one of these. OSA is caused by a repeated narrowing or collapse of the upper airway. Someone with OSA may try to breathe but is only met with further resistance. This leads to excessive daytime sleepiness (EDS), lack of oxygen, and difficulty sleeping. Over time this disorder can cause cognitive disruptions due to neuron cell loss and vascular issues from the lack of sleep. This study looks at those with OSA currently using Positive Airway Pressure (PAP) treatment. Nine participants who were diagnosed with OSA by using the Apnea-Hypopnea Index (AHI), age 25-65 years, English speaking, using PAP treatment and no other medications were used. The participants kept a sleep diary and were given the National adult reading test and the 2-back working memory test. FMRI’s were done after one week of consecutive PAP treatment and after 2 nights without using PAP. The participants were also given the Stanford Sleepiness Scale (SSS) before and after the FMRI scans to see if the scan increased their sleepiness. The 2-back test requires executive coordination, buffering and subvocal rehearsal to be successful at performance. The participants are given a list of letters one at a time and are asked for a yes or no response after each letter. Whole brain FMRI scans showed that while receiving treatment the posterior insula, parietal lobe, posterior cingulated of the right hemisphere and the supplementary motor cortex in the left are turned on. After two days without treatment the activity in these areas decreased. The less sleep a participant had the larger the decrease in these areas. Functional impairment in these areas while withholding treatment is common. The participants also had problems with visual processing and were more distracted than usual. With treatment they all performed normally.