Table 4.
VBM studies in OSA.
| Reference | VBM specification | OSA patients |
Healthy controls |
Major findings | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | Age (years) | BMI | AHI | N | Age (years) | BMI | AHI | |||
| (10) | p < 0.001 uncorrected for multiple comparisons, extent threshold = 350 voxels, patients were not screened for cardiovascular or psychiatric comorbidities | 21 Men (2 were left-handed) | 49 ± 11 | 30 ± 4 | RDI 38 ± 24 events/h | 21 Men (4 were left-handed) | 47 ± 11 | 27 ± 4 | N/A | GM-volume loss in patients was reported in the right postcentral gyrus, posterior lateral parietal cortex bilaterally and anterior superior frontal cortex bilaterally, bilateral parahippocampal gyri among others |
| No regions had higher gray matter volume in patients and no difference between groups was found for white matter | ||||||||||
| (11) | p < 0.05 corrected for multiple comparisons, patients were not screened for cardiovascular or psychiatric comorbidities | 7 Men | 7 Men | GM-concentration is lower in patients in left hippocampus | ||||||
| No further significant GM-concentration differences between groups | ||||||||||
| GM-volume was not different between groups | ||||||||||
| (12) | p < 0.001 uncorrected for multiple comparisons (optimized VBM), effects of 6 months of CPAP treatment, two patients and one control subject were excluded from VBM analysis | 27 Men | 45.7 ± 10.1 | 33.2 ± 4.7 | 71.7 ± 17.0 | 24 Subjects | 43.3 ± 9.4 | 25.3 ± 2.8 | 5.9 ± 4.7 | GM-volume loss in patients was reported in the posterior and mesial temporal lobe bilaterally and the left insular region |
| GM-volume increase in patients as compared to healthy controls was reported in the right basal ganglia and less prominently in scattered frontal lobe and parietal lobe areas | ||||||||||
| (24) | p < 0.005 uncorrected for multiple comparisons at voxel level, p < 0.05 corrected at cluster level (optimized VBM), patients were not screened for cardiovascular comorbidities | 16 Patients (15 M: 1 W) | 54.8 ± 5.7 | N/A | 38.3 ± 14.3 | 19 Subjects from a brain database in France, although not screened for sleep apnea | 55.3 ± 6.7 | N/A | N/A | GM-concentration loss in patients in the frontal and temporo–parieto–occipital cortices, the thalamus, some of the basal ganglia and the cerebellar regions, mainly right-lateralized |
| No information was provided as to whether OSAS patients also displayed regions of higher GM-volume as compared to healthy controls | ||||||||||
| (16) | p < 0.05 and cluster size > 200 (FDR correction for multiple comparisons), modulated and unmodulated data | 36 Men | 44.7 ± 6.7 | 26.0 ± 2.7 | 52.5 ± 21.7 | 31 Subjects | 44.8 ± 5.4 | 25.8 ± 3.3 | 2.8 ± 0.9 | GM-volume showed no regional differences between OSAS patients and health controls |
| GM-concentration reduction in OSAS patients was found in left gyrus rectus, bilateral superior frontal gyri, left precentral gyrus, bilateral frontomarginal gyri, bilateral anterior cingulate gyri, right insular gyrus, bilateral caudate nuclei, bilateral thalami, bilateral amygdalo-hippocampi, bilateral inferior temporal gyri, and bilateral quadrangular and biventer lobules in the cerebellum | ||||||||||
| There was no region with higher GM-concentration in patients than healthy controls | ||||||||||
| GM-volume and -concentration showed no correlation with clinical parameters (age, AHI, arousal index, and Epworth sleepiness scale) | ||||||||||
| (25) | p < 0.05 at cluster level (FDR correction for multiple comparisons) (optimized VBM), two different sites of MRI acquisition | 60 Patients (57 M: 3 F) | 47.3 (44.2–50.3) Mean (95% CI) | 32.0 (30.9–33.1) | 55.0 (48.3–61.6) | 60 Subjects (55 M: 5 F) | 46.1 (43.2–49.0) | 25.0 (24.1–25.9) | 4.1 (3.0–5.1) | GM-volume decreased in patients in the right middle temporal gyrus and cerebellar regions |
| No information was provided as to whether OSAS patients also displayed regions of higher GM-volume as compared to healthy controls | ||||||||||
| (17) | p < 0.001 uncorrected for multiple comparisons, p < 0.05 cluster-wise family-wise error correction | 16 Patients (13 M: 3 F) | 55.8 ± 6.7 | 31.7 ± 4.4 | 52.5 ± 26.0 | 14 Subjects (9 M: 5 F) | 57.6 ± 5.2 | 25.5 ± 2.4 | N/A | Global cortical GM-volume reduced in patients |
| GM-volume decreased in patients in the right hippocampus (p < 0.05 PFWE). In addition to the following areas: left hippocampus and some lateral temporal of both hemispheres (p < 0.001 uncorrected) | ||||||||||
| WM-volume decreased in patients in the right temporal lobe | ||||||||||
| (14) | p < 0.05 cluster-wise family-wise error correction, p < 0.005 uncorrected at voxel level, effects of 3 months of CPAP treatment | 17 Men | 44.0 ± 7.6 | 31.2 ± 4.4 | 55.8 ± 19.1 | 15 Men | 42.2 ± 6.6 | 26.1 ± 2.5 | 1.6 ± 1.5 | GM-volume decreased in patients in the left posterior parietal cortex, right superior frontal gyrus, and left parahippocampal gyrus. A negative correlation with AHI, desaturation duration <90%, and GM-volume in left posterior parietal cortex |
| GM-volume showed no increases in patients | ||||||||||
| Global cortical GM- and WM-volumes were different between groups | ||||||||||
| GM-volume showed no significant reduction in patients following CPAP. | ||||||||||
| GM-volume increased in patients in the hippocampal and frontal structures following CPAP, which was also correlated with AHI and desaturation duration in the right entorhinal cortex and left subiculum | ||||||||||