Diagnostic and Therapeutic Tests

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Nocturnal Polysomnogram Protocol


Mandatory Test Components for N-PSG Sleep Study:
•  Electroencephalogram (EEG) central channels C3/M2 and C4/M1;   
    occipital channels O1/M2 and O2/M1
•  Electrooculogram (EOG) minimum of 2 channels ROC/M1 and LOC/M2
•  Electromyogram (EMG) submental (chin) 2 channels
•  Electromyogram (EMG) bilateral anterior tibialis (leg) EMG one channel 
    for each leg
•  Electrocardiogram (ECG) two lead ECG
•  Nasal/Oral Airflow thermistor or thermocouple or pressure transducer at the oral/nasal airway
•  Respiratory Effort -- piezoelectric belts -- two channels (chest and 
•  Arterial Oxygen Saturation -- Oximeter with finger probe
•  Body Position -- video monitoring system with manual input
•  Additional channels as requested

Nasal CPAP/BILEVEL Titration

The nasal cpap/bilevel titration study is used to treat those patients who have documented respiratory related sleep disorders, such as obstructive sleep apnea/hypopnea syndrome (OSAS) and upper airway resistance syndrome (UARS). The goal of cpap/bipap is to improve the overall quality of the patient's sleep by reducing or eliminating the presence of sleep-disordered breathing, decreasing the number of arousals, stabilizing oxygen saturation, and eliminating snoring.

As with the diagnostic sleep study, patients spend a full night at the sleep laboratory. Patients are attached to the same medical equipment as used in the diagnostic study with one exception; the sensor used to measure airflow in the first study is replaced with a nasal CPAP interface which delivers air at variable pressure setting.

The test permits the interpreting physician to determine total sleep time, sleep efficiency, the relative percentages of NREM and REM sleep, sleep stage latencies, respiratory function versus body position (including the presence of snoring), oxygen saturation, the presence of periodic limb movements, and arousal indices which are then compared to the results of the initial, diagnostic sleep study. The physician also interprets the CPAP pressure setting which provides the optimal sleep quality.

Multiple Sleep Latency Test (MSLT)

Mandatory Test Components for MSLT: 

  • EEG --  central channels C3/M2 and C4/M1; occipital channels O1/M2 and O2/M1
  • EOG -- ROC/M1 and LOC/M2 
  • EMG -- submental (chin) EMG two channels 
  • ECG --  two lead ECG

Overview of MSLT:

The MSLT is a diagnostic test used most commonly for patients suspected of having narcolepsy or excessive daytime sleepiness (EDS).

The test consists of a minimum of four naps and is performed after completion of a N-PSG. This combination of tests permits the interpreting physician to establish the duration and quality of sleep associated with the patient in the night immediately preceding the MSLY.

In patients referred for narcolepsy, the purpose of the MSLT is to determine whether REM sleep is present during a nap, elapsed time to REM sleep as well as elapsed time to sleep onset. These quantitative measures assist the interpreting physician in the diagnosis of narcolepsy and EDS.

Schedule of Naps:

After the patient is awoken from an overnight study, he/she is asked to get dressed into his/her street clothes and must stay awake before initiation of the first nap and between naps. This will require the sleep technologist on duty to deep a watchful eye to ensure that the patient does not fall asleep between nap sessions.

The first nap commences between a minimum of 1½ hours up to a maximum of 3 hours after completion of the overnight PSG and typically begins between 07:30 - 8:00 am. The MSLT is to be conducted in a dark, quiet setting with minimal extraneous stimuli which might otherwise influence the results of the test.

•   There are a minimum of 4 naps, each ranging in length from a

    minimum of 20 minutes to a maximum elapsed time of 35 minutes

    depending upon the specific events which occur during each specific


•   Naps are equally spaced and begin successively at two hour past the

    initiation of the prior nap (i.e. Nap 1 - 07:30am, Nap 2 - 09:30am,

    Nap 3 - 11:30am, Nap 4 - 13:30pm, if needed Nap 5 - 15:30pm.)


      Maintenance of Wakefulness Test


The MWT is a diagnostic test used in the sleep laboratory to test a patient's ability to maintain wakefulness. This test is often required for patients whose work requires driving, (i.e. truck drivers, bus drivers and pilots) or to determine if a patient's drivers license can be reinstated.

MWT Protocol:

Mandatory test period components for MWT:

•  EEG

•  EOG

•  EMG

•  ECG


Test schedule:

After the patient is awoken from an overnight study, he/she is asked to get dressed into his/her street clothes and must stay awake at all times before the initiation of the first test and between all test periods.

The MWT is to be conducted in a low lit, quiet setting with minimal extraneous stimuli which might otherwise influence the results.

•  4 test periods lasting up to 40 minutes each

•  Test periods are equally spaced and begin successively at 2 hours past

    the initiation of the prior test. (Test 1 at 07:30, Test 2 at 09:30, Test 3

    at 11:30, Test 4 at 13:30)

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