Sleep Tests

One of the best tools for detecting a sleep disorder is the sleep study. Sensors are used to monitor how your body acts while you sleep. Charts are made of your brain waves, heart beats, breathing and other factors. Your sleep study provides the physician with the data that will help them find the cause of your sleep problem.  Our sleep center has been granted accreditation & stamp of approval from the American Academy of Sleep Medicine (AASM).  Being accredited by the AASM means that we have met the high standards in the field of sleep medicine.

Overnight Sleep Study 
Doctors call this study a polysomnogram. It is used to help detect a variety of sleep disorders. It is most often used to find out if someone has a sleep related breathing disorder. This group of disorders includes sleep apnea.

Nap Study
Doctors call this study a Multiple Sleep Latency Test (MSLT). This is mainly used to find out if someone has narcolepsy. It charts how well you fall asleep and how quickly you enter REM sleep.

CPAP Study
This study is used to set the right air pressure for CPAP therapy in patients with sleep apnea.

Polysomnogram (PSG) is a continuous and simultaneous recording of physiological variables during sleep, i.e., EEG, EOG, EMG (the three basic stage scoring parameters), EKG, respiratory air flow, respiratory excursion, lower limb movement, and other electrophysiological variables by a trained health care professional.


Electroencephalography (EEG) is a "brain wave" test. It is similar to an EKG of the heart. (Both organs operate with electricity.)

An EEG is performed by glueing electrodes onto the scalp and recording the underlying brain activity though the skull. It is non-invasive and does not hurt. It can be done on patients of all ages. A routine EEG takes about 30 minutes to perform and has no after effects. Patients are sometimes asked to either stay up late the night before or awaken very early on the day of the EEG since the test is generally better if one falls asleep during the recording.

Extended EEGs are available for patients whose routine EEG fails to pinpoint the abnormality and/or the brain activity needs to be monitored during the seizures. These can be done over 24 hours or more while the patient is either in the hospital (in a monitoring unit) or at home. A portable unit which resembles a "walkman" can be worn as an outpatient for a day or more.

Electromyography (EMG) and Nerve Conduction (NCV) tests
Both together usually called simply an "EMG"

The first part of the test is generally a nerve conduction test which reveals how well the nerves conduct electrical signals/impulses to the muscles they control. It employs some moderate electrical stimulation of the arms and legs which feel like "static shocks" one might feel in the wintertime when there is low humidity or "static electricity." Most patients report that the test is slightly uncomfortable but not painful.

The second part of the test which is usually done is the actual EMG. A small wire (needle smaller than that used to draw blood) is placed into a few of the muscles to make a recording. The patient initially is asked to relax and then activate the muscle being tested gently. Minimal discomfort is involved. No shocks are delivered but the small needle does "pinch" or feel like a brief "bee sting."

There are no after-effects of the test (for example, the patient can return to their daily activites as usual, work, etc.)

Results of the test will be sent to the referring doctor's office immediately.

An EMG is usually done to evaluate for entrapped nerves ("pinched nerves"). Common diagnoses include carpal tunnel syndrome and cervical and lumbar radiculopathies (pinched nerve roots as they exit the spine). Peripheral neuropathies are common and are usually from chronic diabetes. Less common entities include demyelinating neuropathies (CIDP and Guillain Barre syndrome), primary muscle disorders (myopathies) and neuromuscular junction disorders (myasthenia gravis).

Imaging Studies
Computed Tomography scan (CAT scan or CT scan)

This type of scan is often done of the brain to assess for structural brain lesions or strokes. It is still the state of the art way to detect intracranial hemorrhage (bleeding into the brain). It is also used to screen for brain lesions in headache and may be used to screen for secondary causes of dementia. It is relatively inexpensive and is a "quick and easy test".
CT scans are done of the spine and assess for bony abnormalities and/or spinal canal stenosis (narrowing of the fluid filled space around the spinal cord itself). It is generally better than MRI to asess bony changes.

Magnetic Resonance Imaging (MRI)

This test is more expensive and more cumbersome to perform but is, for many disease processes, more likely to illustrate structural abnormalities. It may take up to an hour to perform and patients with claustrophobia may have some difficulty with the test. However, Opelousas General hospital provides ways to help the test be more comfortable, with a goggles type hardware device to watch a movie during an MRI. Open MRI magnets are slightly weaker than conventional MRI. Your doctor may have preferences for a certain magnet in your special situation.

Patients with implanted pacemakers and some types of implanted metal (some brain aneurysm clips) may be unable to go into an MRI and a CT would have to be performed. Welders or patients with a history of metal flakes in the eyes would need orbital x-rays prior to MRI to be safest.