None listed
Conditions
Brief summary
Neurocognitive impairments in Obstructive Sleep Apnoea (OSA) are likely related to a combination of factors including low oxygen levels during sleep (hypoxia), sleep fragmentation and possibly elevated carbon dioxide levels (hypercapnia). The latter, unlike hypoxia, has not been explored in depth and is often viewed as an innocent bystander. Early detection of hypercapnia may be an important step in the prevention of neurocognitive dysfunction in Obesity Hypoventilation Syndrome (OSA/OHS). In this study, neurocognitive function of patients with sleep disordered breathing will be assessed before and after 3 months of positive pressure mask therapy. Hypothesis 1. Patients with OHS exhibit greater cognitive impairment than obese patients with obstructive sleep apnea (OSA), but without daytime hypercapnia. 2. Patients with sleep hypoventilation have less sleep fragmentation but greater neurocognitive impairment arising from a longer exposure to hypercapnia. 3. Although correction of hypercapnia with PAP treatment will at least partially improve cognitive function, patients with OHS may remain impaired relative to treated OSA patients without hypercapnia.
Interventions
Neurocognitive function testing, sleep studies and EEG analysis, arterial blood gas and questionnaires will be performed before and after 3 months of positive airway pressure therapy.
Positive airway pressure will be titrated to determine optimal pressure settings for each patient. Either CPAP or Bilevel will be applied via a full face or nasal mask interface for the 3 month duration. Patients will be advised to use this therapy each night. Positive airway treatment is part of standard care.
Neurocognitive function testing, sleep studies and EEG analysis, arterial blood gas and questionnaires will be performed before and after 3 months of positive airway pressure therapy. Positive airway pressure will be titrated to determine optimal pressure settings for each patient. Either CPAP or Bilevel will be applied via a full face or nasal mask interface for the 3 month duration. Patients will be advised to use this therapy each night. Positive airway treatment is part of standard care. In addition to monthly phone calls to monitor use of therapy, positive airway pressure devices will be downloaded at 3 months to obtain objective compliance data. Participants are patients with obesity hypoventilation syndrome (OHS). By definition, they will have elevated carbon dioxide levels (hypercapnia).
Sponsors
Sheila Sivam
Eligibility
Sex/Gender
All
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
1. Age 18 – 75 years old 2. Written informed consent 3. Daytime CO2 > 45 (OHS) or < 45 (Control) 4. Evidence of definite OSA on polysomnography, with an AHI >20 /hr OR evidence of sleep hypoventilation if AHI <20/hr * Increase in TcCO2 to a value > 55mmHg for >10 mins or * Increase in TcCO2 > 10 mmHg (compared with awake PaCO2) to a value > 50 mmHg for > 10 mins) 5. BMI>40kg/m2 6. pH is in the normal range for chronic hypercapnia 7. FEV1/FVC ratio > 0.7
Exclusion criteria
1. Major psychiatric, neurological disorder or head injury 2. Neuromuscular disease or lung disease 3. FEV1/FVC ratio <0.7 4. Uncontrolled medical conditions including cardiac failure 5. Alcohol consumption >30 g/day or on medications potentially affecting cognitive testing or EEG recordings such as opiates, benzodiazepines, anti-depressants and anticonvulsants (unless on stable low dose). 6. Not proficient in English
Outcome results
None listed