Home Sleep Testing

Question 1

Under what conditions does medicare cover sleep testing?

Answer 1

PSG in a facility-based study (Type I)
HST (Type II, II, IV)
Must be ordered by a treating physician and conducted by Medicare provider of sleep tests

Question 2

What is “first night effect” and how does it affect sleep?

Answer 2

Not the regular sleep surroundings, similar to hotel, etc. Artificially prolonged sleep latency
Reduced sleep efficiency (# of hours asleep as % of # of hours in bed) because of tossing and turning, waking up more during the night)
Chest 2000, 118:353-359
Reduced time in REM and slow-wave sleep
Higher arousal index

Question 3

How does first night effect influence AHI, and why?

Answer 3

AHI will be artificially underestimated because:
AHI is higher during REM
Because sleep is interrupted, person may not get into stages of sleep where apneic events occur (reduced sleep efficiency and lower arousal threshold)
Chest 2000, 118:353-359

Question 4

Why is PSG an imperfect gold standard?

Answer 4

First night effect leads to inaccurate assessment of sleep architecture and underestimation of AHI.
Night-to-night variation in sleep.
In patients with high clinical suspicion (excessive daytime sleepiness, snoring, accidents, etc.) a single negative PSG may not exclude the diagnosis because of the factors above.

Question 5

What are the indications for a home sleep test?

Answer 5

Patients who have severe symptoms of sleep apnea (mild or moderate probability are not great candidates for HST)
When treatment is urgent and PSG is not readily available
When behavioral or medical issues prevent study in sleep lab
To evaluate response to therapy
No comorbidities (CHF, severe pulmonary or neuromuscular disease)
No other sleep disorder
≥18 years old (Medicare will not pay for HST on children)

Question 6

What is Medicare’s 2008 guideline for indications for CPAP?

Answer 6

Clinical evaluation AND positive PSG in lab (Type I) as well as HSTs (Type II, III, and IV).

Question 7

What is a Type II sleep test?

Answer 7

PSG in the patient’s home that measures at least 7 channels:

EEG, EMG, EOG, ECG, airflow, respiratory effort, oxygen saturation

Question 8

What is a Type III HST?

Answer 8

4 or more channels including:

respiratory effort, airflow, heartrate, oxygen saturation

Question 9

What is a Type IV HST?

Answer 9

Pulse oximeter, at least three channels that allow direct calculation of AHI or RDI

Question 10

Why are three channels required in Type IV HSTs (POX)?

Answer 10

POX sensitivity: 100% if ODI is ≥25 per hour
POX specificity: 95% if ODI is ≥25 per hour
POX sensitivity: 60% if ODI is 5-15 per hour (due to sampling rate of computer in POX - varies by mfr)
POX specificity: 80% if ODI is 5-15 per hour (due to sampling rate)
Chest 2005, 127:80-88

Question 11

What is sensitivity?

Answer 11

The likelihood that a test will detect a condition.

Question 12

What is specificity?

Answer 12

The likelihood that a test will accurately detect a condition.

Question 13

When did Medicare recognize oral appliances as a valid treatment for OSA?

Answer 13

In 2008, in the change that provided coverage for and recognition of diagnoses from HSTs, Medicare also created policy that oral appliances are a frontline treatment for mild/moderate OSA.

Question 14

What criteria are necessary for HST to be covered by Medicare?

Answer 14

Physician reading the test must be certified by ABSM/ABIM or certified in sleep by another relevant specialty or on staff of a certified sleep lab.

Question 15

What are the advantages of home sleep testing?

Answer 15

The ability to record in a natural sleep environment
Greater availability (decreased wait time)
Decreased cost
Centralization of data analysis (decreased variability)

Question 16

What are the disadvantages of HSTs?

Answer 16

Inability to diagnose other non-breathing-related sleep disorders
Potential of a higher number of invalid studies because unattended
Ghegan et al 2006

Question 17

What are the advantages of Type II home tests (mini-PSG)?

Answer 17

Multiple channels
Flexibility in choosing channels (choose 7 from 16 possible)
Comprehensive (non-SDB sleep disorders)
Uses standard software of a base system
Portable
Good track record

Question 18

What are the disadvantages of Type II studies?

Answer 18

Technician needs to hook it up
Expensive
If lead becomes disconnected, study is lost (unattended nature of study)

Question 19

What are the advantages of Type III studies?

Answer 19

Easy to set up - no technician
Inexpensive compared to PSG
Portable
Reduced number of signals (ease)

Question 20

Disadvantages of Type III (cardiopulmonary study)?

Answer 20

Unattended nature of study (signal loss potential)
Reduced number of signals (only tests SDB)
Requires scoring or overview by certified sleep physician

Question 21

Advantages of Type IV (oximetry plus another channel)?

Answer 21

Most portable
Inexpensive
Easy to set up
Core signals: oxygenation and airflow
Now may include PAT signal (arterial pulse tonometry – indirect measure of sympathetic activity, surrogate marker for apnea/hypoxia, relatively expensive)

Question 22

Disadvantages of Type IV HST (POX + 1 channel)?

Answer 22

Minimal number of signals, may not capture important aspects of some OSA
Signal loss (unattended)

Question 23

What documentation is required in case of audit by Medicare with regards to HST?

Answer 23

Must show that the HST was performed:
In conjunction with a comprehensive sleep evaluation
In patients with a high pretest probability of moderate to severe OSA
HST was a Medicare-approved device, reading center, and ordering physician

Question 24

How do we overcome the challenges of the HST?

Answer 24

Maintain low threshold for ordering full polysomnography
Order full PSG if HST is of poor quality or if diagnosis could not be made despite high clinical probability
Preferred SpO2 sensor is soft rubber finger cap secured with tape or flat sensor secured with adhesive wrap

Question 25

Who monitors activity for Medicare?

Answer 25

Recover audit contractors – several different ones per activity.