Abstract
Gray matter (GM) anomalies may represent a critical pathology underlying obstructive sleep apnea (OSA). However, the evidence regarding their clinical relevance is inconsistent. We conducted a meta-analysis of voxel-based morphometry (VBM) studies of patients with OSA to identify their brain abnormalities. A systematic search was conducted based on PRISMA guidelines, and a meta-analysis was performed using the anisotropic effect-size-based algorithms (ASE-SDM) to quantitatively estimate regional GM changes in patients with OSA. Fifteen studies with 16 datasets comprising 353 untreated patients with OSA and 444 healthy controls were included. Our results revealed GM reductions in the bilateral anterior cingulate/paracingulate gyri (ACG/ApCG), left cerebellum (lobules IV/V and VIII), bilateral superior frontal gyrus (SFG, medial rostral part), right middle temporal gyrus (MTG), and right premotor cortex. Moreover, GM reductions in the bilateral ACG/ApCG were positively associated with body mass index (BMI) and age among patients with OSA, and GM reductions in the SFG (medial rostral part) were negatively associated with Epworth sleepiness scale (ESS) scores and sex (male). These abnormalities may represent structural brain underpinnings of neurocognitive abnormalities and respiratory-related abnormalities in OSA. In particular, this study adds to Psychoradiology, which is a promising subspecialty of clinical radiology mainly for psychiatric disorders.
Highlights
In most epidemiological studies, the definition of obstructive sleep apnea (OSA) is based on the apnea-hypopnea index score (AHI), which reflects the degree of departure from the normal physiology of breathing during sleep
One of the included studies, which was conducted by Huynh et al.[19], separated the OSA patients into two groups: patients treated with a sham continuous positive airway pressure (CPAP) device and those treated with an active CPAP device
Our study identified consistent and robust regional gray matter (GM) alterations in patients with OSA compared with healthy controls
Summary
The definition of OSA is based on the apnea-hypopnea index score (AHI) (the number of obstructive respiratory events per hour during sleep), which reflects the degree of departure from the normal physiology of breathing during sleep. Celle et al.[25] stated that measuring GM volume changes in patients with OSA would not yield valid results unless large cohorts were studied to permit statistical control for various clinical and demographic confounding influences. In addition to these qualitative observations, coordinate-based meta-analyses have been used to facilitate quantitative analyses combining data from different studies. It included updated literature, the meta-analysis conducted by Tahmasian et al.[33] explored only convergent brain changes on VBM and resting-state fMRI studies Such a combination might fail to identify all regions with anatomic alterations. Both software platforms are coordinate-based, there are some inherent differences between them, e.g., SDM takes the p value of each coordinate into account, while ALE does not
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