NCT07674264 · University of Florida
Cross-System Effects of Acute Intermittent Hypercapnia-Based Interventions in PD
What this study is about
Parkinsonism impairs upper airway and axial motor control, leading to disordered breathing, reduced speech volume, and ineffective cough. Symptoms are poorly addressed by current therapies.
View original scientific description
Parkinsonism impairs upper airway and axial motor control, leading to disordered breathing, reduced speech volume, and ineffective cough. Symptoms are poorly addressed by current therapies. This randomized pilot trial tests whether a single session of acute intermittent hypercapnic hypoxia (AIHH) or hypercapnic normoxia (AIHN) improves upper airway and axial motor function in Parkinsonism, and explores biomarker correlates of intervention responsiveness.
Interventions
OTHER
Acute intermittent hypercapnic hypoxia (AIHH)
Participants randomized to Group 1 will breathe brief bouts of AIHH, involving 15, 1.5-min exposures to 9-10% O2 and 4-5% CO2, alternated with 1 minute of 21% O2 (room air).
OTHER
Acute intermittent hypercapnic normoxia (AIHN)
Participants randomized to Group 2 will breathe brief bouts of AIHN, involving 15, 1.5-min exposures to 21% O2 and 4-5% CO2, alternated with 1 minute of 21% O2 (room air).
Primary outcome measures
Change in speech loudness
Time frame: baseline and 60 minutes post-intervention
Within-subject differences in sound pressure level (decibels) pre/post intervention and differences between intervention groups (AIHH vs. AIHN) during sustained phonation and connected speech.
Change in maximum phonation duration
Time frame: baseline and 60-minutes post-intervention
Within-subject differences in duration (s) of sustained "ah" pre/post intervention and differences in duration between intervention groups (AIHH vs. AIHN).
Change in peak expiratory flow rate during voluntary cough
Time frame: baseline and 60 minutes post-intervention
Within-subject differences in peak expiratory flow rate (L/s) produced during maximal volitional cough production, pre/post intervention, and between group (AIHH vs. AIHN) differences in peak expiratory flow rate.
Change in Five-Times Sit-to-Stand performance
Time frame: baseline and 60 minutes post-intervention
Within-subject differences in average time (s) to complete 5 times sit-to-stand task, pre/post intervention, and differences between intervention groups (AIHH vs. AIHN).
Change in Timed Up and Go performance
Time frame: baseline and 60 minutes post-intervention
Within-subject differences in duration (s) of Timed Up and Go performance, pre/post intervention. This includes duration of time participants take to stand, walk 3m, turn, walk back 3m, and sit. Differences in duration will also be compared between intervention groups (AIHH vs. AIHN).
Change in fast walking speed
Time frame: baseline and 60 minutes post-intervention
Within-subject differences in duration (s) of 10M walk test, pre/post intervention. Differences in duration will also be compared between intervention groups (AIHH vs. AIHN)
Correlation between blood-based biomarkers and functional outcomes
Time frame: Baseline and 60 minutes post-intervention; genotype assessed at baseline only
Relationship between baseline biomarkers (APOE and BDNF genotype, inflammatory cytokines, serum urate, and circulating α-synuclein) and differences in speech loudness (dB), phonation duration (s), TUG (s), 5x sit-to-stand, and 10M walk test, pre/post intervention in both AIHH and AIHN intervention groups.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- adults 40 to 75 years of age (the latter to reduce the likelihood of cardiovascular disease)
- diagnosis of idiopathic Parkinsonism with Hoehn and Yahr stages 2-4
- medically stable with physician clearance
- ability to ambulate at least 10 feet with/without assistance
- ability to follow directions
- willing to abstain from blood donation for the duration of the study
Exclusion criteria
- additional neurologic conditions
- severe illness or infection, including respiratory/cardiovascular/lung disease, or uncontrolled hypertension
- inspiratory stridor
- pregnancy due to unknown tAIH effects on a fetus, although females of childbearing age will not be excluded\
- cigarette smoking or vaping within 5 years
- history of head/neck/lung cancer with the exception of basal cell carcinoma
- is currently participating in another research study that could influence the results from this study
- has deep brain stimulation electrodes implanted or has a history of deep brain stimulation
- faints or becomes lightheaded at the sight of blood
- If a female of childbearing potential indicates there is a chance she could be pregnant, she will be provided a pregnancy test and allowed to continue in the study if negative. This is because the fetal risks associated with intermittent hypoxia are unknown.
Where
- Gainesville, Florida
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 29, 2026 · Source of record for eligibility and locations