Proefschrift_vd_Beek

Bottom quarter ASM

Lower middle quarter ASM

Upper middle quarter ASM

–9

Top quarter ASM

–12

T-level (dB)

–15

T-level Predicted values

–18

a

1 + 2

3 + 4

Electrode duo 9 + 10 5 + 6 7 + 8

1 + 2

3 + 4

Electrode duo 9 + 10 5 + 6 7 + 8

1 + 2

3 + 4

Electrode duo 9 + 10 5 + 6 7 + 8

1 + 2

3 + 4

Electrode duo 9 + 10 5 + 6 7 + 8

11 + 12

13 + 14

15 + 16

11 + 12

13 + 14

15 + 16

11 + 12

13 + 14

15 + 16

11 + 12

13 + 14

15 + 16

1.00

0.80

0.60

r-value

0.40

0.20

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).

0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Electrode of single measurement

b

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 ).

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-

opulation-Based Prediction of Fitting evels

9

Audiol Neurotol 2015;20:1–16 DOI: 10.1159/000362779

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104 | Chapter 5