clinical
Evaluation of the sleepy patient
Mohammad Torabi Nami
Background
Inefficient sleep leading to excessive daytime sleepiness is a common complaint
encountered by GPs and sleep physicians. Common causes of excessive daytime
sleepiness include circadian rhythm disorder/shiftwork, sleep apnoea syndrome,
psychiatric disorders, restless leg syndrome, medication effect, narcolepsy and
idiopathic hypersomnia.
Objective
This short review discusses the available objective and subjective testing measures
in office evaluation of sleepy patients, predominantly in the primary care setting.
Discussion
Beyond affecting patients’ quality of life, mood and functionality, excessive
sleepiness can become a public health concern when affecting critical job holders.
Therefore, a clear understanding of its importance and applying current standards
in evaluating patients with such a complaint are of great necessity. Apart from the
clinical assessments, including a thorough history taking and physical examination,
measures to assess sleepiness and ability to maintain wakefulness are available.
Keywords
disorders of excessive somnolence; sleep apnoea syndromes; general practice
Daytime sleepiness is defined as the
‘inability to stay awake and alert during
the major waking episodes of the day,
resulting in unintended lapses into
drowsiness or sleep’.1 Sleepiness may
vary in severity and is more likely to occur
in boring, monotonous situations that
require no active participation.
Excessive daytime sleepiness (EDS) is a common
presentation to general practitioners and sleep
physicians. Excessive daytime sleepiness can
adversely affect quality of life and also impair
mood, personal relationships and functional
status. Although a common presentation, EDS
may be under recognised. In the 2000 Sleep
Foundation Gallup Survey conducted in the United
States, 20% of respondents reported that daytime
sleepiness interfered with their daily activities,
8% fell asleep at work and 19% made errors
at work because of sleepiness, yet 61% of the
respondents reported their primary physician had
never asked how well they slept.2
In a comprehensive survey, 16% of
respondents reported sleeping too much (primary
hypersomnia), 30% showed sleepy behaviours all
day, 15% had night time awakenings followed by
EDS and 2.5% experienced problems with work.3
Excessive daytime sleepiness caused by
chronic sleep deprivation has been implicated in
major catastrophes, including the Exxon Valdez oil
spill and the space shuttle Challenger explosion.4
Sleep apnoea, chronic insomnia and
parasomnias may affect cardiovascular,
neurological and psychiatric status of sufferers,
leading to increased morbidity and even mortality
in severely afflicted patients.5
Excessive daytime sleepiness is not only a
personal health issue but also a public safety
concern, meaning that it is important to be
able to accurately screen and identify EDS and
provide proper treatment.
Common causes of EDS include sleep
related breathing disorder, insufficient sleep
time, circadian rhythm disorder and shiftwork,
psychiatric disorders, restless leg syndrome,
medication effect, narcolepsy, idiopathic
hypersomnia (with or without long sleep time)
and various related medical conditions.6,7
In comparison with narcolepsy, which is
characterised by an abnormal propensity to fall
asleep, idiopathic hypersomnia with long sleep
time can be viewed as an inability to terminate
sleep. Idiopathic hypersomnia without long
sleep time could belong to the spectrum of
narcolepsy.
Clinical evaluation
History taking
The most important step in evaluating EDS is a
detailed history from the patient and their family
members. Snoring, witnessed apnoea, excessive
sweating, gasp arousals, nocturia and choking
Reprinted fom Australian Family Physician Vol. 41, No. 10, October 2012 787
clinical Evaluation of the sleepy patient
or coughing while asleep are suggestive of sleep
related breathing disorder.
The history should include total sleep time
during the week days and ‘catching up on sleep’
on weekends. The use of the snooze function on
alarm clocks can be indicative of sleep inertia
and insufficient sleep.
Patients who do shiftwork and those who
frequently travel in different time zones (jet
lag effect) experience sleepiness as a normal
physiological response to the time of day. Many
shiftworkers develop chronic partial sleep
restriction and may experience somnolence
even when they are on a daytime schedule.
Consider the patient’s work schedule, including
working hours per day and fixed versus rotating
schedules. If they have a rotating schedule,
ascertain whether the rotations are weekly or
monthly, and forward versus backward.
A long commute to work can significantly
shorten sleep duration and can cause chronic
partial sleep deprivation. The use of tactics
while driving to stay awake, such as rolling the
windows down, playing loud music, snacking and
even slapping oneself, are all indicative of EDS.
Restless leg syndrome can be diagnosed
by the history alone. Restless leg syndrome is
characterised by disagreeable leg sensations that
usually occur before sleep onset, an irresistible
urge to move the limbs, and partial or complete
relief from discomfort upon leg movements.
These symptoms can lead to significantly reduced
sleep time, leading to daytime sleepiness.
Adverse effects of many medications can
also result in EDS. Such medications include
analgesics, antidepressants, benzodiazepines,
antipsychotics and beta-blockers. In addition,
common over-the-counter drugs such as
antihistamines can have the same effect. The
current or past use of recreational drugs, including
alcohol, should be discussed. Sudden withdrawal
from stimulants such as cocaine or amphetamines
can also cause significant sleepiness.
Ask about sleep paralysis, cataplexy,
hypnogogic hallucinations and sleep attacks
(irresistible desire to sleep). In addition,
the history should include asking about the
irresistible need for naps throughout the day
and whether the naps are refreshing or not. A
diagnosis of narcolepsy should be considered in
sleepy patients with a clear history of cataplexy.
788 Reprinted fom Australian Family Physician Vol. 41, No. 10, October 2012
In patients with idiopathic hypersomnia, naps
are not refreshing; whereas in narcoleptics, short
naps can be effective.
Physical examination
The physical examination of a patient should
include measurement of body mass index and
neck circumference. Examine the oral cavity for
tongue size and note the presence of a narrow
arched palate, tonsillar hypertrophy, retrognathia,
micrognathia and crowded oral pharynx. Nasal
septum deviation, allergies, swollen turbinates
and nasal polyps are risk factors for sleep related
breathing disorder. The Mallampati classification
is very helpful in evaluating airway size.8 It has
been shown that a high Mallampati score and
nasal obstruction are risk factors for obstructive
sleep apnoea (Figure 1).9,10
Measures of sleepiness
It is very hard to quantify sleepiness, either
subjectively or objectively, however some
methods have been developed to attempt to
determine the severity of a patient’s sleepiness.
Another limiting factor is the fact that sleepiness
is not well defined. It is difficult to differentiate
chronic fatigue from excessive sleepiness. There
are some subjective and objective assessments of
propensity to fall asleep or ability to stay awake.
Subjective
Epworth Sleepiness Scale
First described by Johns in 1991, the Epworth
Sleepiness Scale (ESS) is one of the most
frequently used tools to assess sleepiness.11 The
questionnaire describes eight situations:
• sitting and reading
• watching television
• sitting inactive in a public place
• as a passenger in a car riding for an hour
without a break
• lying down to rest in the afternoon when
circumstances permit
• sitting and talking with someone
• sitting quietly after lunch without alcohol
• being in a car while stopped for a few minutes
in traffic.
The patient will score each situation on a scale
of 0–3 (0 = would never doze; 1 = slight chance
of dozing; 2 = moderate chance of dozing and 3 =
high chance of dozing). A total score of 11 or more is
suggestive of EDS.
Being subjective, this instrument has a wide
margin of error and patients’ motivation should
be considered when analysing the results: for
example, is the patient trying to get their driver’s
licence reinstated?
While the ESS may not correlate well with
objective measurements, it is still widely used and
has proven to be an effective screening tool.11
Note that ESS results do not always accurately
reflect severity of the underlying condition and
should be followed up with objective tests.12
Stanford Sleepiness Scale
While the Epworth Sleepiness Scale measures
overall propensity to fall asleep during various
mundane activities, the Stanford Sleepiness
Scale measures the current state of sleepiness. It
consists of the following seven statements:
• Feeling active, vital, alert or wide awake
• Functioning at high levels, but not at peaks; able
to concentrate
• Awake, but relaxed; responsive but not fully
alert
• Somewhat foggy, let down
• Foggy; losing interest in remaining awake;
slowed down
• Sleepy, woozy, fighting sleep; prefer to lie down
• No longer fighting sleep, sleep onset soon;
having dream-like thoughts.13
The patient chooses the statement that most
accurately describes their current state of
sleepiness. The advantage of the Stanford
Sleepiness Scale is that it can be administered
multiple times during the day; however the
disadvantage is that it cannot differentiate
between acute sleep deprivation and an underlying
sleep disorder.
Karolinska Sleepiness Scale
Another instrument, which is very similar to the
Stanford Sleepiness Scale, is the Karolinska
Sleepiness Scale. This questionnaire requires
the patient to choose one statement that best
describes his or her current state of alertness.
The detrimental states of alertness are classified
as: extremely alert, very alert, alert, rather alert,
neither alert nor sleepy, some signs of sleepiness,
sleepy/no effort to stay awake, very sleepy/great
effort to keep awake/fighting sleep.14
Evaluation of the sleepy patient clinical
Class I
Class II
Objective measures of
wakefulness
Maintenance of Wakefulness
Test
Class III
Class IV
Figure 1. Mallampati classification of upper airway
Adapted from Huang H, et al. BMC Gastroenterology 2011, 11:12 doi:10.1186/1471230X-11-12, under the terms of the creative commons attribution license
Karolinska and Stanford sleepiness scales
are measures of state (immediate) sleepiness.
They are probably less useful when administered
while the patient is at the clinic; a measure
would be more useful if it reflected sleepiness
while driving or probed a more general ‘trait’, like
degree of sleepiness.
Sleep diary
A patient’s sleep diary can give insight into the
cause of the patient’s sleepiness. The patient is
asked to maintain this log for 2 weeks, recording
bedtime, wake time, number of arousals, time it
takes to return to sleep after an arousal, the use
of a sleep aid, and any other relevant symptoms.
It is particularly helpful for identifying sleep
fragmentation, insufficient sleep time, circadian
rhythm sleep disorder and insomnia.
Objective measures of
sleepiness
Polysomnogram
A polysomnogram (PSG) is performed to rule
out obstructive sleep apnoea as the cause
of sleepiness. The PSG typically includes an
electroencephalogram (EEG), electro-oculogram,
electromyogram, electrocardiogram, respiratory
channels and oxygen saturation. An ApnoeaHypopnea Index (AHI) of more than 15 per hour of
sleep is diagnostic for a sleep related breathing
disorder. Although not indicated for restless leg
syndrome, the PSG can help identify periodic limb
movements as a cause of sleep disruption. A
PSG is also done a night before a Multiple Sleep
Latency Test to ensure the patient achieved an
adequate amount of sleep.
Multiple Sleep Latency Test
A Multiple Sleep Latency Test (MSLT) is primarily
indicated for evaluation of narcolepsy and
idiopathic hypersomnia. The MSLT assesses
the patient’s propensity to fall asleep. The test
consists of five 20 minute nap opportunities. An
overnight PSG, performed the night before, is
required to ensure the patient attained adequate
sleep. The first nap is 1.5–3 hours after the PSG,
with each subsequent nap taken 2 hours apart.
Sleep latency is calculated by averaging the time
from lights out to sleep onset during each nap
period. In addition, the occurrence of rapid eye
movement (REM) sleep during the 20 minute nap
period (sleep onset REM period, or SOREMP)
should also be noted. Sleep latency greater than
11 minutes is considered normal. Sleep latency of
less than 8 minutes can be seen in patients with
idiopathic hypersomnia. However, a mean sleep
latency of less than 8 minutes with the presence
of two or more SOREMPS is highly indicative of
narcolepsy. The trends for sleep propensity appear
to be identical in narcoleptic patients with or
without cataplexy.15,16
Whereas the MSLT tests the propensity to fall
asleep, the Maintenance of Wakefulness Test
(MWT) assesses the ability of an individual
to stay awake. It is often done to verify the
effectiveness of therapy in which sleepiness
can be a significant public health risk, such as
in the airline and trucking industries. The MWT
protocol consists of four 40 minute nap periods,
conducted 2 hours apart. Performing a PSG a
night before the test is not required. The patient
sits in a semi-reclined position in a dim, quiet
room and is asked to stay awake; a mean sleep
latency of less than 8 minutes is considered
abnormal. An MWT value between 8 and 40
minutes is inconclusive and is of uncertain
significance.13,15–17
The ‘steer clear’ reaction time
In this test a two lane street is shown on
the computer screen. The patient is asked to
press a button to avoid obstacles that appear
randomly in either lane during the 30 minute
test period. Instead of measuring reaction time,
the number of ‘hits’ are counted and presented
as a percentage of all obstacles encountered.18
Pupillometry
The size of one’s pupil is controlled by inputs
from the parasympathetic and sympathetic
nervous systems. In a state of drowsiness the
parasympathetic tone predominates, resulting
in miosis, while in a state of arousal there is
increased sympathetic tone. A well-rested
person is able to maintain a stable pupil size
without much oscillation in 15 minutes of total
darkness. Pupil size and stability are inversely
related to the degree of sleepiness. Presently,
pupillometry is not used widely in clinical
practice. Being a portable, brief and objective
measure, this test should not be undervalued
and further research is necessary to determine
the role of pupillometry in the assessment of
sleepiness of various origins.18,19 Other ocular
based measures of sleepiness such as those
measuring eyelid drooping are being applied
mostly in research settings.
Reprinted fom Australian Family Physician Vol. 41, No. 10, October 2012 789
clinical Evaluation of the sleepy patient
Oxford Sleep Resistance Test
The Oxford Sleep Resistance Test can be used as
a surrogate for the MWT. Behavioural elements
are used in lieu of an EEG to determine sleep
onset. The subject is asked to respond to a flash
of light lasting 1 second, which lights up every
3 seconds. Sleep onset is defined as the failure
to respond to the light for seven consecutive
illuminations.18,20 The test is performed in four 40
minute sessions held 2 hours apart.
Summary
Excessive sleepiness is a common condition that
has a significant public safety risk. Insufficient
sleep and chronic sleep deprivation secondary to
sleep related breathing disorder are the two most
common causes of hypersomnia.
People with tight shiftwork schedules,
intentional chronic sleep restriction, witnessed
sleep apnoea or self reported nonrefreshing
sleep with subjective daytime sleepiness may be
patients who are at an increased risk of motor
vehicle accidents and work related injuries, as well
as significant cardiovascular diseases and mood
disorders. Patients suspected to have this increased
risk should be carefully evaluated by general
practitioners and then, if deemed needed, referred
for further assessment.
Subjective measures to assess sleepiness
are good for screening. However, they should
not replace a detailed history and physical
examination. Some screening tools can be
used for sleepy patients in primary care, such
as the sleep diary; the Epworth, Karolinska and
Stanford Sleepiness scales; and the Oxford Sleep
Resistance Test. The Oxford Sleep Resistance Test,
for instance, can be used as a surrogate for the
MWT, which will reduce the burden on overloaded
sleep laboratories.
It often becomes mandatory to conduct
evaluation in a sleep laboratory (eg. using PSG,
MSLT and MWT) to obtain an accurate diagnosis
and appropriate therapeutic intervention.
Author
Mohammad Torabi Nami MD, PhD, is Lecturer,
Department of Neuroscience, School of Advanced
Medical Science and Technologies, Shiraz
University of Medical Sciences, Shiraz, Iran.
torabi_m@iricss.org.
Conflict of interest: none declared.
790 Reprinted fom Australian Family Physician Vol. 41, No. 10, October 2012
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