Choosing a Sleep Study
An overnight sleep study at a
sleep centre has always been the standard diagnostic
test for detecting obstructive sleep apnea (OSA)
and remains the 'gold standard' in diagnosis . Recent
advances have made home sleep testing another option for
people who are at risk for OSA.
SleepMed is able to provide both services, catered for
the individual patient to give the best possible
outcome. Follow our simple
flow chart
in our referral protocol to assist you in making a
decision. The table below is a summary of the main
advantages and disadvantages of the 2 options.
|
CLINIC (LAB)
STUDY |
HOME (PORTABLE)
STUDY |
Methodology |
Standardised |
Non-standardised.
Types 2, 3 and 4 devices vary in sophistication
and data collection |
Data collection |
Maximal – includes
EEG, EOG, EMG, EFT, ECG, respiratory effort,
airflow changes, oxygen Sats, snoring, body
position and leg movements
|
At SleepMed, we use
a Type 2 device which is the one most resembling
a lab-based PSG. EEG, EOG, EMG, ECG, respiratory
effort, airflow, oxygen Sats, body position +/-
leg movements are also monitored. |
Technician |
Overnight
technician attendance |
Not supervised |
Data credibility |
More credible
- technician
is available during the night to ensure
quality of data collected is acceptable
- less data
loss
|
Less credible
- patient may
operate equipment incorrectly
- higher data
loss. Without professional supervision,
electrodes can fall off, causing loss of or
less accurate signals.
|
Ability to detect
sleep disorders |
Able to detect all
sleep disorders. |
Mostly used for
detecting obstructive sleep apnoea and helpful
for a handful of others |
Portability
|
study must be
conducted in a sleep lab. |
may be conducted in
patient’s home. |
Contraindications |
None |
Contraindications
include (see
guidelines):
- suspected
disorders other than sleep apnea
- co-morbid
conditions
|
Diagnostic Limits
A Clinic based sleep study detects many other sleep
disorders in addition to OSA. These include central
sleep apnea, restless legs syndrome and parasomnias.
They are effective if you have multiple medical problems
or other suspected sleep disorders. A standard home
sleep test detects OSA best. It does not record the
signals needed to detect other sleep disorders
accurately. Having particular medical problem or other
suspected sleep disorders may affect the results of a
home sleep test. This includes suspected hypoventilation
(from morbid obesity, co-existing severe respiratory
problems) or central sleep apnoea (eg heart failure or
neurological conditions).
Age Limits
Home sleep tests may be inadequate for older adults who
are likely to have other medical problems or sleep
disorders that affect sleep. Validation research for
this group has not been done.
Information Recorded
The study gathers signals about physiological parameters
with each parameteron its own “channel.” Lab based
studies record at least 12 channels. The system used by
SleepMed Australia gathers at least 10 channels of
information. In a clinic based study, the signal
fidelity can be checked in real time and if a lead does
not register, falls of or there are other technical
issues, they are attended by the technician. With
portable studies, this is not possible. However in only
a minority of cases will there be insufficient data to
necessitate re-testing.
Therapy Evaluation
The standard treatment for OSA is CPAP. In order to
maximise therapy and ensure proper control or for
troubles with the device, a CPAP-titration study may be
required. A sleep technologist “titrates” the air
pressure, raising or lowering it to reach an ideal
setting. A lab-based sleep study is ideal for this. If a
home sleep test detects that you have OSA, then you may
be able to begin treatment at home with autotitrating
CPAP (APAP). An APAP unit has an automatic,
self-adjusting mode that raises or lowers the air
pressure as needed.
Availability & Costs.
At SleepMed, we aim to cater for all sleep disorders and
for all our patients’ wishes and circumstances. Whilst
the clinic based studies are more labour intensive and
costly to run, if you have private health cover, it may
end up actually cheaper than a home study. Some insurers
require a dedicated clinic study before paying towards
the costs of your CPAP. Please call us on 1300 484 707
and we can assist you or your patients in which test
best suits them.