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106 | Chapter 5
DISCUSSION
The present paper demonstrates how the group profile of Tand M-levels in a relatively large population
can be described in closed-set formulas and how this can serve as a starting point for fitting individual
cochlear implant recipients. With the help of equations 2–5, the measure-ment of the Tand M-level at just
one electrode contact along the array suffices to obtain a prediction of Tand M-levels along the array (fig.6;
table 3), which can be ap-plied in a simplified and time-efficient fitting procedure. In particular, it can be a
Population-Based Prediction of Fitting
Levels
Audiol Neurotol 2015;20:1–16
DOI: 10.1159/000362779
11
Table 3.
Prediction errors and r-values per individual electrode contact (prediction based upon a randomly chosen subset of 30% of the
subjects)
a
T-levels
Electrode Valid,
n
Prediction errors (dB)
Mean
±
1.96 SD Prediction errors (CU)
Mean
±
1.96 SD
r
mean var
95% prediction
interval
r
mean var
95% prediction
interval
1
49
0.92
0.61
2.06
–2.2 to 3.4
0.92
3
139
–20 to 26
2
5
0.86
0.10
1.46
–2.3 to 2.5
0.87
0
35
–12 to 12
3
49
0.94
0.38
1.62
–2.1 to 2.9
0.94
2
107
–19 to 22
4
39
0.94
0.38
1.02
–1.6 to 2.4
0.96
2
32
–9 to 13
5
16
0.98
0.06
0.82
–1.7 to 1.8
0.99 –1
82
–19 to 17
6
39
0.98
0.21
0.33
–0.9 to 1.3
0.99
1
8
–4 to 7
7
50
1.00
0.00
0.00
0.0 to 0.0
1.00
0
0
0 to 0
8
39
0.98
0.00
0.44
–1.3 to 1.3
0.98
0
15
–8 to 7
9
16
0.99
0.13
0.42
–1.1 to 1.4
1.00
0
22
–9 to 9
10
39
0.98 –0.09
0.49
–1.5 to 1.3
0.97 –1
27
–11 to 9
11
50
0.97 –0.18
0.84
–2.0 to 1.6
0.98 –2
54
–16 to 13
12
39
0.95 –0.38
0.93
–2.3 to 1.5
0.95 –3
49
–17 to 11
13
50
0.94 –0.24
1.65
–2.8 to 2.3
0.96 –3
128
–25 to 19
14
6
0.94
0.57
0.74
–1.1 to 2.2
0.93
3
35
–8 to 15
15
50
0.85 –0.38
3.86
–4.2 to 3.5
0.88 –4
370
–42 to 34
16
37
0.90 –0.64
1.69
–3.2 to 1.9
0.89 –6
151
–30 to 18
b
M-levels
Electrode Valid,
n
Prediction errors (dB)
Mean
±
1.96 SD Prediction errors (CU)
Mean
±
1.96 SD
r
mean var
95% prediction
interval
r
mean var
95% prediction
interval
1
49
0.96 –0.01
0.77
–1.7 to 1.7
0.95 –3
786
–58 to 52
2
5
0.92 –0.34
0.89
–2.2 to 1.5
0.91 –4
220
–33 to 25
3
49
0.97
0.00
0.58
–1.5 to 1.5
0.97 –1
542
–47 to 44
4
39
0.95
0.21
0.61
–1.3 to 1.7
0.97
3
281
–29 to 36
5
16
0.99 –0.08
0.37
–1.3 to 1.1
0.98 –2
507
–46 to 42
6
39
0.96
0.04
0.42
–1.2 to 1.3
0.98
0
214
–29 to 28
7
50
1.00
0.00
0.00
0.0 to 0.0
1.00
0
0
0 to 0
8
39
0.97
0.09
0.31
–1.0 to 1.2
0.99
2
134
–21 to 25
9
16
1.00 –0.09
0.16
–0.9 to 0.7
1.00 –4
135
–27 to 19
10
39
0.97 –0.11
0.35
–1.3 to 1.1
0.98 –2
235
–32 to 28
11
50
0.99 –0.25
0.19
–1.1 to 0.6
0.98 –6
444
–47 to 35
12
39
0.97 –0.14
0.38
–1.4 to 1.1
0.98 –2
493
–45 to 42
13
50
0.99 –0.31
0.28
–1.3 to 0.7
0.98 –8
557
–54 to 38
14
6
0.95 –0.67
0.53
–2.1 to 0.8
0.97 –13
122
–35 to 8
15
50
0.98 –0.34
0.47
–1.7 to 1.0
0.97 –8
663
–59 to 42
16
37
0.96 –0.18
0.67
–1.8 to 1.4
0.98 –2
611
–50 to 47
var = variance.
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