Season 8 | Episode 9

In this episode of Talking Sleep, host Dr. Seema Khosla welcomes Dr. Lee Neilson, Assistant Professor of Neurology at the University of Iowa and staff neurologist at the Iowa City VA specializing in movement disorders, to discuss his groundbreaking research examining whether obstructive sleep apnea represents a modifiable risk factor for Parkinson’s disease.

Dr. Neilson’s ambitious study analyzed records from 13 million patients within the VA system to investigate whether OSA is associated with higher risk of neurodegenerative disorders and whether treating sleep apnea might help delay the onset of dementia. The conversation traces the research design from initial hypothesis through methodology, explaining how he narrowed this massive dataset and defined both OSA diagnosis and Parkinson’s disease progression.

Critical methodological details emerge: How was OSA diagnosed—through sleep testing, and using 4% or 3% hypopnea criteria? How did the study differentiate between mild and severe sleep apnea? How was Parkinson’s disease identified—through clinical notes, medication records, or longitudinal follow-up? Dr. Neilson clarifies whether the analysis included only PD or extended to other neurodegenerative disorders like Alzheimer’s disease.

The core findings receive extensive examination: Did CPAP therapy have a modifying effect on PD risk? After adjusting for confounding factors including BMI, diabetes, depression, and hypersomnia, which variables mattered most? What was the number needed to treat to prevent one case of Parkinson’s disease? Could hypoxic burden be examined as a potential mechanism?

Intriguing tangential discussions explore whether idiopathic RBD can be distinguished from trauma-related RBD and whether these represent separate pathological processes. The conversation takes an unexpected turn into the neuroprotective effects of smoking in Parkinson’s disease, with Dr. Neilson explaining proposed mechanisms and drawing parallels to ischemic preconditioning that might occur with OSA.

The episode addresses severity gradients—did OSA severity correlate with PD risk? It also tackles a fundamental question: Does treating sleep apnea delay dementia onset or actually prevent it? Dr. Neilson discusses whether non-PAP therapies were examined and addresses a critical ethical concern in sleep apnea research: Is it irresponsible to withhold treatment from symptomatic patients, and did this study focus on non-sleepy individuals or include all OSA patients regardless of symptoms?

This research has profound implications for how sleep medicine practitioners frame the importance of OSA treatment with patients and families. Beyond addressing immediate symptoms like sleepiness, treating sleep apnea may reduce long-term neurodegenerative risk—a compelling motivation for adherence that extends beyond quality of life to disease prevention.

Whether you’re counseling patients about the importance of OSA treatment, interested in the sleep-neurodegeneration connection, or seeking evidence-based approaches to discussing long-term benefits of therapy, this episode provides essential insights.

Join us for this important conversation about how the work sleep medicine practitioners do every day may profoundly impact patients’ neurological futures.

Dr. Neilson: Dr. Neilson is an Assistant Professor of Neurology at the University of Iowa and a staff neurologist at the Iowa City VA who specializes in all aspects of movement disorders. He has a special clinical and research interest in Parkinson’s disease and its prodromal state. A graduate of Case Western Reserve University school of medicine and the Portland VA Medical Center advanced fellowship in movement disorders, he started his faculty career at Oregon Health & Science University where he served as the co-director of the movement disorders fellowship. He recently joined the University of Iowa to continue his research focused on risk factor identification, biomarker development, and metabolism in PD.

Resources

    1. Sleep apnea and neurodegeneration study. JAMA Neurology. https://jamanetwork.com/journals/jamaneurology/fullarticle/2841763
    2. Defining Parkinson’s disease using VA medical records. National Institutes of Health (PMC12983286). https://pmc.ncbi.nlm.nih.gov/articles/PMC12983286/
    3. Defining Parkinson’s disease using VA medical records (validation study). National Institutes of Health (PMC11832812). https://pmc.ncbi.nlm.nih.gov/articles/PMC11832812/
    4. Hearing loss and hearing aid use in Parkinson’s disease. National Institutes of Health (PMC11581660). https://pmc.ncbi.nlm.nih.gov/articles/PMC11581660/
    5. Uvulopalatopharyngoplasty and Parkinson’s disease risk. National Institutes of Health (PMC8100168). https://pmc.ncbi.nlm.nih.gov/articles/PMC8100168/
    6. CPAP use and dementia risk. National Institutes of Health (PMC8436135). https://pmc.ncbi.nlm.nih.gov/articles/PMC8436135/
    7. CPAP and symptom improvement in Parkinson’s disease. National Institutes of Health (PMC5940433). https://pmc.ncbi.nlm.nih.gov/articles/PMC5940433/