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104 | Chapter 5
opulation-Based Prediction of Fitting
evels
Audiol Neurotol 2015;20:1–16
DOI: 10.1159/000362779
9
y the following quadratic function with only electrode
2
duo
nd electrode
duo
as significant parameters:
T-level
(
electrode
duo
) = 0.04 ×
electrode
2
duo
+ 0.03 ×
electrode
duo
(
in dB
).
(1)
he interaction of electrode
duo
with the ASM of T-levels
id not reach significance (p > 0.05).
To predict the T-level for each 16 separate electrodes
for an individual subject, instead of the 8 electrode duos,
electrode
duo
from equation 1 should be substituted by
(½ × electrode + ¼). Finally, the overall level can be de-
termined by measuring the T-level measurement of one
electrode. It turned out that the best prediction (with a
mean correlation coefficient of r = 0.94 over the whole ar-
T-level (dB)
–18
T-level
Predicted values
Electrode duo
Bottom quarter
ASM
Upper middle
quarter ASM
Lower middle
quarter ASM
Top
quarter ASM
1 + 2
3 + 4
5 + 6
7 + 8
9 + 10
11 + 12
13 + 14
15 + 16
–15
–12
–9
Electrode duo
1 + 2
3 + 4
5 + 6
7 + 8
9 + 10
11 + 12
13 + 14
15 + 16
Electrode duo
1 + 2
3 + 4
5 + 6
7 + 8
9 + 10
11 + 12
13 + 14
15 + 16
Electrode duo
1 + 2
3 + 4
5 + 6
7 + 8
9 + 10
11 + 12
13 + 14
15 + 16
a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Electrode of single measurement
r-value
0
0.20
0.40
0.60
0.80
1.00
b
ig. 5.
a
Measured and predicted T-levels fitted with a random70%
f the population. Data plotted in quartile groups of ASM.
b
Dis-
ribution of r-values fitting with single T-level measures at differ-
nt electrodes (electrodes 2, 5, 9 and 14 not included; electrodes
ctive in less than 33% of the subjects).
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Fig. 5.
a Measured and predicted T-levels fitted with a random 70% of the population. Data plotted in quartile groups of ASM. b Dis-
tribution of r-values fitting with single T-level m as res at differ- ent lectrodes (electrod s 2, 5, 9 nd 14 not included; ctrodes active
in less than 33% of the subject ).