See how the evidence changes the letter

For clinician review. Not a signed medical opinion. FICTIONAL EXAMPLE. Do not submit as evidence.

[CLINICIAN: letterhead: practice name, address, phone]

[CLINICIAN: date]

RE: [VETERAN: full name], [VETERAN: last four of SSN or VA file number]

Medical nexus opinion: Obstructive sleep apnea aggravated beyond its natural progression by service-connected PTSD

To whom it may concern:

I am a [CLINICIAN: specialty and board certification] physician licensed in [CLINICIAN: state and license number]. [CLINICIAN: relationship to the veteran: treating since (date), or records review only]. I was asked to give a medical opinion on whether the veteran's obstructive sleep apnea was aggravated beyond its natural progression by the veteran's service-connected PTSD. For this opinion, I reviewed in full the March 22, 2016 rating decision, September 5, 2018 baseline sleep study, January 27, 2020 equipment follow-up, February 20, 2024 later sleep consultation, and the veteran's statement; the supplied materials contained no medical literature. I have reviewed the records listed below in full, and I have reviewed the medical literature cited at the end of this letter.

Records reviewed

1. Rating decision, dated March 22, 2016, page 1.
2. Baseline sleep study, dated September 5, 2018, page 2.
3. Equipment follow-up, dated January 27, 2020, page 3.
4. Later sleep consultation, dated February 20, 2024, page 4.
5. The veteran's written statement describing the history, symptoms and course, as supplied to me.

Pertinent history

The March 22, 2016 rating decision granted service connection for PTSD. That decision made no determination concerning sleep apnea.

The September 5, 2018 baseline sleep study assessed obstructive sleep apnea based on an untreated diagnostic apnea-hypopnea index of 16 events per hour. The study discussed prescribed positive airway pressure at follow-up.

The January 27, 2020 equipment follow-up documents that the veteran tolerated the prescribed mask and felt rested after using it. That note contains no repeat untreated sleep study and does not quantify progression of the underlying obstructive sleep apnea.

The February 20, 2024 later sleep consultation documents that the veteran removed the mask during awakenings associated with nightmares and reported daytime fatigue. The consultation also documents weight gain and a different work schedule. The clinician requested further assessment of equipment use and sleep history but did not attribute worsening of obstructive sleep apnea to PTSD. The veteran's statement similarly reports fatigue and difficulty keeping the mask on during disrupted sleep.

Current diagnosis

The September 5, 2018 baseline sleep study states the diagnosis of obstructive sleep apnea, established by an untreated diagnostic apnea-hypopnea index of 16 events per hour. Positive airway pressure was prescribed, and the January 27, 2020 equipment follow-up documents use of the prescribed mask with reported benefit. As of the February 20, 2024 later sleep consultation, the veteran continued to have positive airway pressure equipment but reported removing the mask during awakenings.

Opinion

It is less likely than not (less than a 50 percent probability) that the veteran's obstructive sleep apnea is aggravated beyond its natural progression by the veteran's service-connected PTSD. The record does not establish a measurable increase in the underlying severity of obstructive sleep apnea after the September 5, 2018 baseline sleep study, and it does not medically attribute an increase in severity to PTSD.

Rationale

Obstructive sleep apnea involves repeated upper-airway obstruction during sleep. Positive airway pressure prevents or reduces these obstructive events while the equipment is worn. Removing the mask can reduce the effectiveness of treatment for the portion of sleep spent without therapy, but reduced treatment exposure does not by itself establish that the underlying airway disorder has become more severe. To establish aggravation beyond natural progression, the record should show an increase in the severity or clinical burden of obstructive sleep apnea and should distinguish that increase from interrupted treatment, weight change, work schedule effects, and the expected course of the condition.

No verified medical study was provided in the materials for this opinion, and there is no study cited at the end of this letter from which to draw a veteran-specific conclusion. A general association between PTSD, disturbed sleep, weight change, and obstructive sleep apnea would not establish aggravation in this case without documentation that PTSD produced a worsening of this veteran's obstructive sleep apnea beyond its natural progression.

The veteran's documented facts show a pathway for reduced treatment effectiveness but not a demonstrated increase in the underlying apnea. The January 27, 2020 equipment follow-up records mask tolerance and feeling rested after use. The February 20, 2024 later sleep consultation records mask removal during awakenings associated with nightmares and daytime fatigue. This change documents less complete positive airway pressure use. The consultation does not connect the nightmares to PTSD, does not state that PTSD worsened the underlying obstructive sleep apnea, and does not provide a repeat untreated apnea-hypopnea index.

The timing does not establish objective continuity of worsening. The September 5, 2018 baseline sleep study provides the only untreated measure of severity, with an apnea-hypopnea index of 16 events per hour. The January 27, 2020 equipment follow-up reports benefit from treatment but contains no repeat untreated study. The February 20, 2024 later sleep consultation reports fatigue and difficulty maintaining mask use, but it also contains no comparable untreated diagnostic measurement. The record therefore does not show when an increase in the underlying apnea began, how large any increase was, or whether it continued independently of treatment use.

The contrary factors are incomplete mask use, weight gain, a different work schedule, daytime fatigue, and the absence of a comparable later untreated study. The February 20, 2024 later sleep consultation documents all of these factors except a later untreated study, which it does not contain. Daytime fatigue does not identify whether the cause is untreated apnea during mask removal, disrupted sleep, the changed work schedule, weight-related change, or progression of the underlying disorder. The record does not quantify the weight gain or attribute it to PTSD. The supplied record set also contains no prior medical opinion to reconcile.

For aggravation, the September 5, 2018 untreated apnea-hypopnea index of 16 events per hour is the documented baseline. The later evidence shows subjective fatigue and interruption of positive airway pressure use, but it does not show a later untreated apnea-hypopnea index or another comparable measure demonstrating that the obstructive sleep apnea itself worsened. It also does not establish that any worsening exceeded natural progression or resulted from PTSD rather than interrupted equipment use, weight gain, or a different work schedule. A favorable aggravation opinion would require a comparable later measure or clearly documented increase in obstructive sleep apnea burden, together with medical evidence attributing that increase to PTSD beyond natural progression.

Summary of the basis for this opinion

1. The September 5, 2018 baseline sleep study is the only untreated objective measure of obstructive sleep apnea severity.
2. The January 27, 2020 equipment follow-up documents benefit from prescribed mask use without measuring progression.
3. The February 20, 2024 consultation documents mask removal and fatigue but no comparable untreated sleep study.
4. Weight gain and a different work schedule are documented competing factors, and the record does not attribute the weight gain to PTSD.
5. No record medically attributes worsening of the veteran's underlying obstructive sleep apnea to PTSD beyond natural progression.

Conclusion

For these reasons, it is less likely than not (less than a 50 percent probability) that the veteran's obstructive sleep apnea is aggravated beyond its natural progression by the veteran's service-connected PTSD. The record documents interrupted positive airway pressure use and fatigue, but it does not document objective worsening of the underlying obstructive sleep apnea or medical attribution of such worsening to PTSD. I am available to provide further explanation of this opinion.