Comparison of automated and traditional ECAP recording approaches in clinical practice

Figures & data

Table 1. Details on the demographic of the study participants. All implants were manufactured by MED-EL (Innsbruck, AUSTRIA).

Participant ID	Side	Implant Type	Electrode Type	Gender	Aetiology	Age (y)	Time_of_use (y)
S01_1	right	SONATAti100	Standard	male	Hyperbilirubinemia	8	5
S01_2	left	CONCERTO	FLEX28	male		8	2
S02	right	PULSARci100	Standard	male	Unknown	14	10
S03_1	right	SONATAti100	Standard	female	Hereditary	6	5
S03_2	left	SONATAti100	Standard	female		6	3
S04	right	SONATAti100	Standard	male	Unknown	10	7
S05_1	right	SONATAti100	Standard	female	Premature birth	11	8
S05_2	left	CONCERTO	Standard	female		11	2
S06_1	right	PULSARci100	Standard	female	Meningitis	11	9
S06_2	left	SONATAti100	Standard	female		11	2
S07_1	right	SONATAti100	FLEX28	male	Unknown	7	3
S07_2	left	SONATAti100	Standard	male		7	2
S08_1	right	SONATAti100	Standard	male	Waardenburg	11	3
S08_2	left	CONCERTO	Standard	male	syndrome	11	2
S09_1	right	SONATAti100	Standard	male	Waardenburg	6	5
S09_2	left	SONATAti100	Standard	male	syndrome	6	5
S10	right	CONCERTO	Standard	female	Unknown	19	1
S11_1	right	PULSARci100	Standard	male	Premature birth	12	10
S11_2	left	SONATAti100	Standard	male		12	4
S12	right	SONATAti100	Standard	female	Unknown	9	4
S13_1	right	SONATAti100	Standard	female	Unknown	10	7
S13_2	left	SONATAti100	Standard	female		10	5

S: subject; R: right; L: left; y: years.

Table 2. Recording parameters and settings for standard ART and FineGrain approaches.

eCAP Settings ART Task MAESTRO 6.0.1 (standard ART)
Min. charge	0
Max. charge/amplitude	individually set (security limit 800 cu)*
Iterations	20
Measurement delay	125 µs
Measurement gap	10 − 13 ms
Phase duration	40 µs
Amplitude Levels	15
Stimulation rate	40 Hz
Settings Research Software (FineGrain RT)
Min. charge	0
Max. charge	individually set (security limit 800 cu)*
Charge change per second	1.5
Phase duration	40 µs
Stimulation rate	40, 60, and 76 Hz

*based on MCL + 5 qu or more or maximum accepted loudness. cu = current units (1 cu ≈ 1 µA); qu = charge units (1 qu ≈ 1 nC).

Figure 1. (A) Correlation analysis of ECAP thresholds determined with the FineGrain RT approach and standard ART. Pearson correlation coefficient (R) and the corresponding p value are shown. (B) Comparison of average ECAP thresholds determined with the FineGrain RT and standard ART. ECAP thresholds from all contacts were pooled. Grey diamond and number indicate the respective mean. The p value indicated on top is the result from a paired T test. qu = charge units (1 qu ≈ 1 nC).

Figure 2. Results from the linear mixed model analysis on the effect of contact position onto ECAP thresholds. Point estimates of the ECAP threshold differences between contacts are shown with their respective confidence interval. Y-axis labels are the compared contacts with the second number being the reference point indicated as dotted line at 0. E.g. 6 – 2 refers to the differences between contacts 6 and 2, with contact 2 as reference point and indicates that contact 6 has lower ECAP thresholds than 2. This difference is significant as the confidence interval of the point estimate does not comprise the reference value. Exact values are shown in Supplemental Table 2. qu = charge units (1 qu ≈ 1 nC).

Figure 3. Correlation analysis of maximum comfort levels (MCLs) with ECAP thresholds determined with the FineGrain RT approach (at a stimulation rate of 60 Hz). Pearson corr. coefficient (R) and corresponding p value are indicated on top of each panel. qu = charge units (1 qu ≈ 1 nC).

Figure 4. Three examples of ECAP amplitude growth functions recorded with ART and FineGrain. Stimulating contacts were 2, 6 and 10 from left to right. FG stands for FineGrain RT. Individual amplitudes are shown in black, as single dots for ART and single dots appearing as line for FineGrain. For ART, the amplitudes that were included for the linear fit by the expert are shown in green. Determined ECAP thresholds are indicated with the respective colour. qu = charge units (1 qu ≈ 1 nC).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, P.E.