Accuracy of automated pure-tone audiometry in population-based samples of older adults

Figures & data

Figure 1. Schematic overview of the selection procedure.

Table 1. Mean differences between automated and manual pure-tone audiometry by age group and test frequency, averaged between left and right ears.

Test frequency [kHz]	0.25	0.5	1	2	3	4	6	8	PTA4	All
	70-year-old participants
Mean difference	−3.3	−3.2	−2.4	0.2	−0.2	−0.6	−3.4	6.2	−1.6	−0.8
SD of difference	7.2	6.6	7.6	8.0	7.8	9.0	9.4	11.6	5.2	9.0
Mean abs. difference	5.8	5.3	5.6	4.8	5.0	6.0	7.0	10.1	5.4	6.1
SD of abs. difference	5.3	5.0	5.7	6.4	6.0	6.7	7.1	8.4	6.0	6.6
Minimum difference	−35	−30	−25	−60	−55	−55	−70	−65	−28.75	−70
Maximum difference	30	25	40	35	40	35	25	40	21.25	40
p value	<0.001	<0.001	<0.001	0.644	0.572	0.132	<0.001	<0.001	<0.001	<0.001
N (Ears)	468	467	468	466	462	456	448	425	456	3660 PTTs
Missing data	1.7%	1.9%	1.7%	2.1%	3.0%	4.2%	5.9%	10.7%	4.2%	2.7%
	85-year-old participants
Mean difference	1.0	0.0	−1.9	−0.9	1.8	−0.7	−3.6	3.1	−1.0	−0.3
SD of differences	9.2	8.1	10.3	7.6	8.3	7.1	8.1	7.4	4.7	8.6
Mean abs. difference	5.6	4.9	5.7	4.8	5.7	5.2	6.5	6.4	5.2	5.5
SD of abs. difference	7.4	6.5	8.8	6.0	6.3	4.9	6.0	4.9	6.6	6.6
Minimum difference	−55	−25	−65	−35	−35	−20	−35	−15	−13.75	−65
Maximum difference	70	55	60	25	30	20	20	25	26.25	70
p value	0.094	1.000	0.005	0.086	0.002	0.199	<0.001	<0.001	0.005	0.003
N (Ears)	219	218	218	211	205	192	169	106	188	1619 PTTs
Missing data	–	0.0%	0.0%	3.7%	6.4%	12.3%	22.8%	51.6%	14.2%	7.6%

p values refer to the probability of the mean differences being equal to zero (one sample T-test). The missing data is due to unreached hearing thresholds at the maximum measurement level of the audiometer.

PTA4: Pure-tone average of 0.5, 1, 2 and 4 kHz; SD: Standard deviation; Abs: absolute; PTTs: pure-tone thresholds

Figure 2. Bland–Altman plots of the difference in pure-tone averages of 0.5, 1, 2 and 4 kHz (PTA4s) obtained with manual and automated pure-tone audiometry. The mean difference (continuous black line) is near zero for both age groups. The dashed lines show the upper and lower limits of agreement, i.e. the mean difference ± 1.96 SD, within which 95% of differences are expected to fall.

Figure 3. Distribution of threshold correspondence within 0, 5, 10, 15 and >15 dB by test frequency and age. The percentages displayed on the bars in the chart specify what proportion of values were within ± 10 dB difference, which is considered clinically accepted.

Table 2. Results of a multiple ordinal regression analysis with the accuracy of automated audiometry as the dependent variable.

Independent variables		OR	95%CI of OR
Gender	Male	–	–
	Female	1.00	0.64 − 1.56
Age	70 Years	–	–
	85 Years	0.81	0.50 − 1.32
Cognitive status	MMSE score	0.92	0.80 − 1.07
Hearing status	PTA4 better ear	1.00	0.98 − 1.02
	PTA4 worse ear	1.00	0.99 − 1.02

None of the considered predictors was significantly associated with the outcome.

Dependent variable: Accuracy of automated pure-tone audiometry on an ordinal scale.

OR: Odds ratio; CI: Confidence Interval; MMSE: Mini Mental State Examination; PTA4: Four-frequency pure-tone average across 0.5, 1, 2 and 4 kHz