Table 2.
Adjusteda baseline brain volumes and annual rates of change in brain volume according to hearing status
| Baseline Volume (cm3)b | Annual Rate of Change (cm3/year) | |||||
|---|---|---|---|---|---|---|
| Normal Hearing Mean (95%CI) |
Hearing Impairment Mean (95%CI) |
Normal Hearing Mean (95%CI) |
Hearing Impairment Mean (95%CI) |
Differencec Mean (95%CI) |
Effect Sized | |
| Global measures | ||||||
| Whole brain | 979.6 (965.7 – 993.6) | 979.9 (962.3 – 997.5) | −7.22 (−7.78 – −6.66)** | −8.42 (−9.17 – −7.67) ** | −1.20 (− 2.17 – −0.22)+ p = .02 |
−0.68 |
| Whole brain (without temporal lobe) | 879.6 (866.8 – 892.4) | 879.8 (863.6 – 895.9) | −6.76 (−7.26 – −6.26)** | −7.72 (−8.38 – −7.05) ** | −0.96 (−1.83 – −0.08)+ p = .03 |
−0.63 |
| vCSF | 29.8 (25.7 – 34.0) | 30.8 (25.6 – 36.1) | 1.30 (1.10 – 1.51) ** | 1.29 (1.01 – 1.56) ** | 0.02 (−0.38 – 0.34) | −0.02 |
| Gray matter | 530.3 (521.4 – 539.2) | 535.1 (523.9 – 546.4) | −2.60 (−3.06 – −2.15) ** | −3.37 (−3.97 – −2.77) ** | −0.77 (−1.56 – 0.02) | −0.62 |
| White matter | 449.5 (439.7 – 459.2) | 444.9 (432.6 – 457.3) | −4.57 (−5.04 – −4.11) ** | −5.08 (−5.69 – −4/46) ** | −0.50 (−1.31 – 0.30) | −0.45 |
| Lobar measures | ||||||
| Gray matter | ||||||
| Frontal | 155.1 (151.9 – 158.3) | 156.9 (152.8 – 160.9) | −0.94 (−1.11 – −0.76) ** | −1.18 (−1.41 – −0.95) ** | −0.24 (−0.55 – 0.07) | −0.50 |
| Temporal | 114.2 (111.9 – 116.6) | 114.8 (111.8 – 117.8) | −0.37 (−0.51 – −0.22) ** | −0.66 (−0.85 – −0.46) ** | −0.29 (−0.54 – −0.04) + p = .02 |
−0.67 |
| Parietal | 85.5 (83.4 – 87.6) | 86.1 (83.5 – 88.7) | −0.74 (−0.84 – −0.63) ** | −0.77 (−0.91 – −0.63) ** | −0.03 (−0.21 – 0.15) | −0.14 |
| Occipital | 75.4 (73.6 –77.1) | 74.2 (72.1 – 76.5) | −0.45 (−0.53 – −0.36) ** | −0.36 (−0.47 – −0.24) ** | 0.09 (−0.06 – 0.24) | 0.55 |
| White Matter | ||||||
| Frontal | 173.6 (169.4 – 177.9) | 173.3 (167.9 – 178.7) | −1.86 (−2.06 – −1.66) ** | −2.09 (−2.36 – −1.83) ** | −0.24 (−0.58 – 0.11) | −0.51 |
| Temporal | 100.3 (97.5 – 103.0) | 99.9 (96.4 – 103.4) | −1.69 (1.84 – −1.54) ** | −1.68 (−1.87 – −1.48) ** | 0.01 (−0.24 – 0.27) | 0.03 |
| Parietal | 97.7 (95.3 – 100.0) | 96.9 (94.0 – 100.0) | −0.30 (−0.41 – −0.18) ** | −0.41 (−0.56 – −0.26) ** | −0.11 (−0.31 – 0.08) | −0.39 |
| Occipital | 45.2 (43.7 – 46.7) | 43.8 (41.9 – 45.7) | −0.13 (−0.24 – −0.02) + | −0.22 (−0.38 – −0.07) * | −0.09 (−0.29 – 0.10) | −0.39 |
Statistical significance:
p < .05,
p < .01,
p <.001
Abbreviations: 95% CI = 95% Confidence Interval; vCSF = ventricular CSF
All models included covariates of ICV, sex, baseline age, hypertension, smoking, hearing impairment, time (years of follow-up from baseline), and two-way interactions of time with hearing impairment, age, and sex
There were no significant differences in baseline brain volumes between individuals with normal hearing and hearing impairment after adjusting for the multiple covariates.
Difference is the (rate of change in hearing impairment) - (rate of change in normal hearing). Therefore, negative values indicate greater annual rates of atrophy in individuals with hearing impairment compared to those with normal hearing.
Effect size is calculated as the difference in rates of change between those with hearing impairment and normal hearing divided by the corresponding standard deviation of the rate of change.