Developmental changes in word recognition threshold from two to five years of age in children with different middle ear status

Figures & data

Figure 1.  Summary of numbers of children completing the test at each session, the numbers of children who would not cooperate or did not understand the test, and those for which testing was not done (e.g. due to time constraints).

Table 1.  Mean WRT at 31 months, by number of toy pairs and number of reversals.

Number of toy pairs	Mean WRT*	n	%
3	29	1	0.1
4	31.1 (15.6)	8	0.8
5	31.7 (10.0)	71	7.3
6	31.6 (8.7)	338	35
7	31.8 (7.4)	554	57
Total	31.7 (8.1)	972	100
Number of reversals
<6	35.3 (12.0)	58	6
6	31.5 (7.8)	914	94
Total	31.7 (8.1)	972	100

*Word recognition threshold dB (A), standard deviation in brackets

Note: Number of cases is 972 rather than 973, as there was one subject with a valid WRT result but missing data for number of toy pairs and number of reversals, so they were not included in these analyses

Table 2.  Mean WRT in cases with normal middle ear function at 31, 43, and 61 months of age. Only subjects with complete data at all three time points were included (n = 340).

Age (months)	31	43	61
WRT*	28.5 (5.0)	23.1 (3.6)	23.2 (3.7)

*Word recognition threshold dB (A), standard deviation in brackets

Table 3.  Association between mean WRT and middle ear status at 31, 43, and 61 months of age.

	Age
	31 months			43 months			61 months
Middle-ear status*	Mean WRT^†	n	Effect size (dB)^‡	Mean WRT^†	n	Effect size (dB)^‡	Mean WRT^†	n	Effect size (dB)^‡
Bilateral normal	29.2 (6.0)	657	Reference	23.7 (4.2)	665	Reference	23.5 (4.0)	703	Reference
Unilateral OME	34.2 (6.0)	98	5.1 (3.7–6.4)	28.1 (4.8)	110	4.4 (3.3–5.5)	28.8 (4.3)	59	5.3 (4.1–6.6)
Bilateral OME	46.0 (8.7)	96	16.8 (15.4–18.1)	39.2 (10.1)	117	15.5 (14.5–16.6)	38.5 (8.9)	68	15.0 (13.8–16.2)
Other	32.7 (5.9)	70	3.4 (1.9–5.0)	28.5 (5.2)	134	4.8 (3.8–5.8)	28.0 (5.5)	120	4.5 (3.6–5.4)
			p ≤ 0.001			p ≤ 0.001			p ≤ 0.001

*Middle-ear status: bilateral normal-type A or C1 tympanograms; bilateral middle-ear effusions-type B tympanograms; unilateral middle-ear effusion-type A or C1 tympanograms in one ear with type B in the other ear; other-grommet, perforation, or type C2 tympanogram in at least one ear

^†Mean word recognition threshold dB (A), adjusted for gender, standard deviation in brackets

^‡Estimated differences in WRT with reference to bilateral normal middle-ear function at each age, 95% confidence interval shown in brackets

Table 4.  Association between WRT and current (and previous) OME status.

OME*	N	Mean WRT^†	Effect size (dB)^‡	OME*			N	Mean WRT^†	Effect size (dB)^‡	WRT significantly different (p ≤ 0.001) to groups
31 m		43 m			31 m	43 m		43 m
–	509	24.8 (24.2, 25.4)	Reference	1	–	–	392	23.3 (22.8, 23.8)	Reference	3, 4
+	78	32.8 (31.4, 34.3)	8.0 (6.5, 9.6)	2	+	–	20	23.3 (21.1, 25.6)	0.1 (−2.3, 2.4)	3, 4
			p ≤ 0.001	3	–	+	28	36.5 (34.6, 38.4)	13.3 (11.3, 15.2)	1, 2, 4
				4	+	+	31	42.3 (40.5, 44.1)	19.0 (17.2, 20.9)	1, 2, 3
									p ≤ 0.001
43 m		61 m			43 m	61 m		61 m
–	497	24.2 (23.7, 24.7)	Reference	1	–	–	424	23.2 (22.8, 23.6)	Reference	3, 4
+	84	29.2 (28.0, 30.4)	5.1 (3.8, 6.4)	2	+	–	28	24.0 (22.4, 25.7)	0.9 (−0.9, 2.6)	3, 4
			p ≤ 0.001	3	–	+	16	38.9 (36.7, 41.1)	15.8 (13.5, 18.0)	1, 2
				4	+	+	21	37.3 (35.4, 39.3)	14.2 (12.2, 16.1)	1, 2
									p ≤ 0.001

*Middle ear status:+OME present bilaterally (bilateral type B tympanograms); – OME absent bilaterally (bilateral type A or C1 tympanograms)

^†Mean word recognition threshold dB (A), adjusted for gender, 95% confidence interval shown in brackets

^‡Estimated differences in WRT (dB) with reference to bilateral normal middle-ear function, 95% confidence interval shown in brackets

Figure 2.  Relationship between 61 month WRT and the better ear PTA (500, 1000, 2000, and 4000 Hz). Linear regression line plotted.

Table 5.  Linear regression analysis relating 61 month WRT (independent variable) to the PTA (dependent variable). N = 962.

PTA frequencies (Hz)*	R^†	Constant	Slope^‡
500, 1000, 2000, 4000	0.7	−9.47	0.80 (0.75, 0.84)
500, 1000, 4000	0.7	−9.56	0.80 (0.76, 0.85)
1000, 4000	0.7	−10.57	0.82 (0.77, 0.87)

*PTA: pure-tone average

^†R: correlation coefficient

^‡95% confidence interval shown in brackets