2017 Sec 1 Green Book

TABLE III. Median (Range) [IQR] Aqueduct Measurements by the Side of the Hearing Loss Relative to the Side of the EVA.

Hearing Loss With EVA

Ipsilateral Opercular Width, mm*

Ipsilateral Midpoint Width, mm †

Contralateral Opercular Width, mm

Contralateral Midpoint Width, mm

Ipsilateral hearing loss Contralateral hearing loss ‡

2.7 (0.1–7.6) [2.1–3.5]

2.05 (0.1–4.1) [1.6–2.55]

1.25 (0.1–4.2) [0.85–1.85]

0.4 (0.1–3.8) [0.2–0.9]

1.1

0.7

2

1.4

Bilateral hearing loss

2.5 (0.4–7.5) [1.95–3.0]

1.5 (0.1–3.6) [1.0–1.9]

1.4 (0.1–1.9) [0.9–1.6]

0.4 (0.1–0.9) [0.1–0.7]

*Comparison between ipsilateral and bilateral hearing loss groups: not significantly different ( P ¼ .09). † Comparison between ipsilateral and bilateral hearing loss groups: significantly different ( P < .0001). ‡ Only 1 subject with unilateral EVA had contralateral hearing loss. IQR ¼ interquartile range (25th and 75th percentile); EVA ¼ enlarged vestibular aqueduct.

eral EVA, although this difference was not statistically significant (41 of 89 ears [46.1%] vs. 25 of 75 ears [33.3%], respectively; P ¼ .1). No difference in hearing loss progression was found when we compared patients with bilateral vs. unilateral hearing loss (55 of 134 [41%] vs. 11 of 30 [36.7%], respectively; P ¼ .7). Additionally, in analyzing patients with unilateral hearing loss, we found a trend toward a higher preva- lence of progression in patients with bilateral vs. unilateral EVA, although this trend was not statisti- cally significant (5 of 8 [62.5%] vs. 6 of 22 [27.3%], respectively; P ¼ .1). In the patients with unilateral EVA and normal hearing, 3 of 37 (8.1%) demonstrated hearing loss progression. However, the rate of progres- sion in these patients was lower than in patients with EVA and hearing loss at initial presentation (65 of 164 [39.6%]; P ¼ .0003) and in the ears of patients with unilateral EVA (25 of 75 [33%]; P ¼ .002). Among the 75 ears in patients with unilateral EVA and hearing loss, there was no difference in the likelihood of hear- ing loss progression between ears with and without EVA (16 of 48 [33.3%] vs. 9 of 27 [33.3%], respectively; P ¼ 1.0, Fisher exact test). For all 201 ears analyzed for progression, the median change in PTA between the initial and final audiogram was 5.0 dB (range, 38.75 to 77.5 dB). For the ears that progressed (n ¼ 68), the annual rate of progression was 4.5 (range, 1.0–63 dB). For all 164 ears with initial hear- ing loss, the median change in PTA between the initial and final audiogram was 6.25 dB (range, 38.75 to 77.5); among the ears with progression (n ¼ 65), the annual rate of hearing loss progression was 4 (range, 1.0–63 dB). The rate of progression was significantly correlated with the midpoint (Spearman rho ¼ 0.41; P ¼ .001), but not with the operculum (Spearman rho ¼ 0.18; P ¼ .16). The midpoint measurement was highly predictive of how fast an individual would progress (taking into account the clustering of ears or that two ears can belong to the same individual; b ¼ .37; standard error ¼ .07; P < .0001). For every 0.37-U increase in the midpoint measurement, the rate of progression per year increased by a factor of 1 dB. The change in PTA was not correlated with either the midpoint (Spearman rho ¼ 0.18; P ¼ .16) or the opercu- lum (Spearman rho ¼ 0.08; P ¼ .5). During our study period, 100 patients with unilat- eral SNHL without EVA who had at least 3 months of follow-up audiometric data were identified. A portion of these patients have been previously described. 32 Twenty-

In the 144 patients with EVA, there were 243 ears with hearing loss. The midpoint and operculum meas- urements of these ears correlated with the PTA of the final audiogram (Spearman rho ¼ 0.20 [ P ¼ .002] and 0.17 [ P ¼ .007], respectively). This was consistent when correlating midpoint and operculum measurements with the HFPTA at the final audiogram (Spearman rho ¼ 0.28 [ P ¼ .003] and 0.23 [ P ¼ .01], respectively). When analyzing only ears with hearing loss and EVA (n ¼ 202), similarly significant correlations were found for PTA measurements (Spearman rho ¼ 0.18 [ P ¼ .01] and 0.14 [ P ¼ .05], respectively). For HFPTA, the corre- lations were slightly stronger (Spearman rho ¼ 0.30 [ P ¼ .004] and 0.25 [ P ¼ .018], respectively). In the ears of patients with EVA who had hearing loss at their ini- tial evaluation (n ¼ 164), significant correlations were found between the PTA and the size of the midpoint and operculum (Spearman rho ¼ 0.22 [ P ¼ .006] and 0.26 [ P ¼ .0009], respectively). For HFPTA, similarly significant correlations were found (Spearman rho ¼ 0.32 [ P ¼ .005] and 0.24 [ P ¼ .04], respectively). Vestibular aqueduct measurements were compared among audiometric phenotypes (Table III). Only 1 patient with unilateral EVA had contralateral hearing loss (mid- point, 1.4; operculum, 2.0). The median midpoint measurement in patients with ipsilateral hearing loss (2.05; range, 0.1–4.1) was greater than this measurement in patients with bilateral hearing loss (1.5; range, 0.1– 3.6; P < .0001). Also, the median operculum measure- ment in patients with ipsilateral hearing loss was greater (2.45; range, 0.1–5.2) than this measurement in patients with bilateral hearing loss (2.05; range, 0.4–7.5; P ¼ .09); however, this difference was not statistically significant. Hearing Loss Progression There were 232 ears in children with 3 months of audiometric follow-up that were included in the analysis of hearing loss progression; 31 ears were excluded from analysis, as they had profound hearing loss (n ¼ 201). At the initial audiometric evaluation, 164 ears had hear- ing loss, and 37 had normal hearing. Overall, 65 of 201 (39.6%) ears had progression. The initial median PTA in the progressive hearing loss group was 53.3 (range, 15–90), and the final median PTA was 78.7 (range, 27.5– 120). The proportion of ears with progressive hearing loss was slightly higher among ears of patients with bilateral EVA compared to ears of patients with unilat-

Laryngoscope 123: June 2013

Greinwald et al.: Unilateral Enlarged Vestibular Aqueduct

137