changes in brain morphology associated with obstructive sleep apnea
DESCRIPTION
CHANGES IN BRAIN MORPHOLOGY ASSOCIATED WITH OBSTRUCTIVE SLEEP APNEA. Mary J. Morrell et al. 2003 Presented by Karen Hu PSYCH 260. WHAT IS OBSTRUCTIVE SLEEP APNEA ?. INTRODUCTION. Obstructive Sleep Apnea (OSA) : Caused by upper airway dysfunction during sleep - PowerPoint PPT PresentationTRANSCRIPT
CHANGES IN BRAIN MORPHOLOGY ASSOCIATED WITH OBSTRUCTIVE SLEEP APNEA
Mary J. Morrell et al. 2003
Presented by Karen Hu
PSYCH 260
WHAT IS OBSTRUCTIVE SLEEP APNEA ?
INTRODUCTION.
Obstructive Sleep Apnea (OSA) : • Caused by upper airway dysfunction
during sleep - repeated arousals/ awakening - periodic breathing
• Breathing stops for ≥ 10 seconds
- episodic hypoxemia • Periods of significant decrease in O2
saturation in the blood
INTRODUCTION.
Obstructive Sleep Apnea (OSA) affects:
• 1-4% of middle aged adults
• 24- 30% of elderly
SYMPTOMS • Excessive daytime sleepiness
and fatigue• Loud snoring • Increased risk of hypertension
and cardiovascular diseases• Cognitive deficits
NO!
INTRODUCTION.
Cognitive Deficits by OSA:
OSA patients have shown impairment in memory, learning and attention
HIPPOCAMPUS: region closely associated with neural processing of memory
- sensitive to hypoxic (low O2) conditions
CURRENT STUDY
• Investigates the effects of OSA on the morphology or structural changes of the brain • Focusing on the CA1
region of HIPPOCAMPUS and other cortical regions
HYPOTHESIS: There would be a focal loss of grey matter within the hippocampus and other cortical areas linked with memory function
METHODS
• MRI scan • Newly OSA diagnosed
patients selected from sleep clinic
• 7 OSA patients and 7 non-apneic controls – Age range= 28-65
yrs old • All male and right
handed
METHODS
• Voxel based morphometry (VBM) • Images were normalized and compared
to a standardized brain template • Signal intensity represented grey
matter concentration• Images were compared to determine
any significance
RESULTS
Control vs. OSA
Significantly lower grey matter concentration in the OSA patients in the LEFT HIPPOCAMPUSby 6%
RESULTS
• NO SIGNIFICANT DIFFERENCE in focal grey matter concentration in the RIGHT HIPPOCAMPUS and other cortical regions
DISCUSSION
• Reduction of grey matter in left hippocampus:– Hippocampal sensitivity to low O2 conditions
cause neurons to die off• Absence of grey matter difference in the right
hippocampus – Due to relatively moderate hypoxemia in the
OSA patients • Repetitive hypoxia reduces neuron excitability in
the CA1 region – Similar effects of sleep deprivation
• Findings emphasize that grey matter loss is associated with less severe OSA
LIMITATIONS
• Small sample size – Limited validity of results and implications
• Obese patients were excluded • Only male subjects used • Could not relate grey matter loss directly to
cognitive deficits or specific characteristics of OSA
FUTURE IMPLICATIONS
- relate severity of OSA to grey matter loss - larger sample size, include females - explore how sleep fragmentation affects brain structure- correlate grey matter loss with cognitive deficits
PERSONAL THOUGHTS
- Short and simplified - Well organized - Easy to understand - Addressed just the
changes in morphology
- At times, lacked detail - Discussion and intro
was weak - Lacked a strong
possible implication
- Did not specify which cortical areas they were comparing
FINAL EXAM SWAG.
Obstructive Sleep Apnea ( OSA) : - repeated arousal, periodic breathing, episodic hypoxemia, fragmented sleep- leads to damage in cortical areas associated with memory and learning, cognitive deficits and excessive daytime sleepiness
Methods- Voxel based, MRI, 7 OSA patients, 7 controls, all right-handed males
Results - significantly lower grey matter in left hippocampus in OSA group - no significant grey matter differences in right hippocampus or other cortical areas - no significant difference in total volume of grey matter
Discussion - low O2 levels may have resulted in grey matter loss in left hippocampus - no significance in right hippocampus due to moderate OSA severity - repetitive hypoxia reduces neuron excitability in CA1 of hippocampus
REFERENCE
Morrell, M.J., McRobbie, D.W., Quest, R.A., Cummin, A.R.C., Ghiassi, R. and Corfield, D. 2003. Changes in brain morphology associated with obstructive sleep apnea. Sleep Medicine, 4, 451-454.
QUESTIONS?