Dr Keith Johnson
Neuropsychiatrist
Sleep disorders: Assessment
Dr Johnson's clinic tends to focus on the management of insomnia disorder, circadian rhythm disorders and parasomnias in adults. Other sleep disorders such as sleep related breathing disorders and disorders of excessive sleepiness are best assessed by respiratory sleep physicians. Dr Johnson's clinic on Thursdays is part of the multidisciplinary sleep clinic at the Woolcock Institute of Medical Research also hosts respiratory sleep physicians, sleep psychologists, neurologists and other health professionals, and has a sleep laboratory able to perform a wide range of investigations for better clarification of an individual's sleep problem.
For many people with a sleep disorder, the treatment they receive is sleep hygiene at their local doctor's office. This is frequently ineffective, largely because the core determinants of poor sleep haven't been identified and addressed.
How are sleep disorders assessed ?
1) Clinical History (60 mins)
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The first step is to take a thorough clinical history which not only involves ask about an individual's nightly schedule but also involves asking about things that can happen during the night (snoring, nightmares, sleep paralysis etc.) and daytime symptoms such as sleepiness, napping, attention, concentration and mood issues. A cross sectional snapshot, that a clinical history provides us about a person's sleep, may not yield sufficiently detailed information and this is why we would suggest investigations.
2) Investigations (might be indicated)
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Overnight Sleep Study (PSG)
Sometimes investigations are warranted. Overnight sleep studies are necessary for conditions such obstructive sleep apnoea, parasomnias (sleep walking etc.), and disorders of excessive sleepiness. In these conditions, an overnight sleep study (what we technically call polysomnography (PSG)) can be useful to improve the accuracy of the diagnosis, where a clinical history is frequently insufficient.
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Actigraphy
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PSG is generally not all that useful for conditions like insomnia and circadian rhythm disorders. This is because people with these disorder frequently exhibit significant night-to-night variability so that a single night of monitoring may not be indicative of what an individual's habitual sleep pattern looks like. For this reason, actigraphy, which determines sleep, by measuring movement and ambient light can be a useful tool, as it can measure a individual's habitual sleep pattern over a significant period of time (usually 7 days).
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Sleep Diaries
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The simplest tool to evaluate sleep is actually a sleep diary. This is also the most cost effective (it's effectively free) and have proven to be sufficiently reliable for many conditions. There are many forms available including free apps that people can download to their smart phone. We frequently combine sleep diaries with actigraphy to make it more accurate.
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