“Below is a link to a 2021 study in Geriatrics that provides preliminary evidence that Oral Appliance Therapy (OAT) with a mouth shield can improve cognitive performance in those with MCI. This is significant because there is no other therapy or medicine that can slow down dementia-related issues, much less, stop the decline and improve cognition like OAT with a mouth shield can!!” – Michael J. Reed, DDS, FAGD Diplomate ABSCD, Diplomate ABDSM
Alzheimer’s disease (AD) accounts for up to 75% of all dementia cases, and associated deaths in the U.S.A. increased by 71% between 2000 and 2013, making AD the sixth leading cause of death in the country. AD often presents with respiratory dysfunctions such as sleep-disordered breathing (SDB).
The brain’s neural network involved in sleep and respiration regulation is complex, with brainstem nuclei playing a key role. Recent evidence suggests that synchronization of these neural connections might be organized by the entry of air into the nostrils during slow respiration. Airflow through the nose is crucial for respiratory entrainment of brain rhythms involved in cortical excitability, synchronized activity within cellular networks, and coordination of sensory coding, memory, and behavior.
Respiratory and Cognitive Interactions
Emotional states, including stress and anxiety, are linked to the limbic system and can modify the rate and depth of breathing. Animal studies indicate that respiration-locked slow-wave oscillations are amplitude-modulated and associated with slow-wave sleep (SWS), which is often reduced in patients with SDB. SDB ranges from snoring to obstructive sleep apnea (OSA) and is associated with various physiological responses, including reduced alertness and cognitive performance.
Evidence shows that SDB-related brain pathology can start early, with significant impacts on gray matter volume in the brainstem and other regions. Since nasal airflow and brainstem nuclei influence respiration, cognition, and autonomic nervous system regulation, investigating respiration activity during sleep may provide insights into the vulnerability in the AD process.
Hypotheses and Intervention
The study tested three hypotheses:
- Respiratory rate (RR) during stable sleep periods differs between cognitively normal (CN), AD, and mild cognitive impairment (MCI) subjects who snore.
- RR fluctuation differs among the three groups in response to Tx after 4 weeks of use.
- RR response to Tx influences Montreal Cognitive Assessment (MoCA) test scores.
The intervention included a midline traction oral appliance to increase upper airway patency and a mouth shield to facilitate nasal breathing. The findings highlight the potential of RR dynamics as an indicator of neural integrity and cognitive function, particularly in relation to the severity of AD and MCI.