Incorporating ceiling effects during analysis of speech perception data from a paediatric cochlear implant cohort

Figures & data

Table 1. Baseline characteristics of included patients arranged by age-at-implantation group.

Implantation age group	1	2	3	4	5	Total no.	p-Value	Test
Age at CI surgery [range in months]	6–12	13–18	19–24	25–30	31–36	54	–	–
Age at CI surgery (median in months)	11	13	23	26	32	54	–	–
No. of implanted children	9	11	11	13	10	54	–	–
Gender (female:male)	3:6	6:5	6:5	7:6	4:6	26:28	ns	Fisher’s exact
Year of birth [range in years]	2002–2009	2001–2009	1999–2008	1995–2006	1996–2001	54	0.006*	Pearson Chi-square
Year of CI surgery [range in years]	2003–2010	2002–2010	2001–2010	1997–2008	1999–2004	54	ns	Pearson Chi-square
ABR hearing loss pre CI (median in dBHL)	90	100	100	100	110	54	0.012*	Independent samples median
ABR hearing loss pre CI [range in dBHL]	90–100	90–110	90–105	95–110	90–110	54	0.005*	Kruskal–Wallis
Age at FU 5 years after CI (median in months)	71	74	85	90	95	54	<0.001*	Independent samples median
Age at FU 5 years after CI [range in months]	64–76	69–77	81–92	83–97	93–97	54	<0.001*	Kruskal–Wallis
Aetiology	–	–	–	–	–	–	ns	Pearson Chi-square
Unknown (non syndromic)	6	4	7	7	8	32	–	–
Connexine	–	1	–	–	–	1	–	–
Syndromic (Beckwith Wiedemann, Waardenburg, Usher)	0	2	2	1	1	6	–	–
Meningitis	3	4	1	5	1	14	–	–
CMV infection	–	–	1	–	–	1	–	–
Disabilities	–	–	–	–	–	–	–	–
Comorbidity	1	–	1	3	4	9	ns	Fisher’s exact
Prematurity	–	1	1	2	1	5	ns	Fisher’s exact
CI surgical techniques	–	–	–	–	–	–	ns	Pearson Chi-square
MPTA	7	9	10	13	10	49	–	–
SMA	2	1	1	–	–	4	–	–
Unknown	–	1	–	-–	–	1	–	–
CI device	–	–	–	–	–	–	0.012*	Pearson Chi-square
Nucleus	6	9	11	13	10	49	–	–
MED-EL	3	2	–	–	–	5	–	–
Unilateral:bilateral	5:4	5:6	10:1	10:3	10:0	40:14	0.018*	Fisher’s exact
Time gap first CI–second CI [range in months]	0–20	0–47	51	0–32	–	–	ns	Kruskal–Wallis
Outcomes	–	–	–	–	–	–	–	–
CVC(A)-score (median in %)	100	97	89	89	75,5	92	<0.001*	Kruskal–Wallis
CVC(A)-score [range in %]	95–100	88–100	77–100	70–95	57–94	57–100	–	–

ABR: auditory brainstem response; CI: cochlear implant; CMV: CytoMegaloVirus; CVC: consonant–vowel–consonant; dBHL: deciBel hearing loss; FU: follow up; MPTA: Mastoidectomy with posterior tympanotomy approach: no.: number; ns: not significant; SMA: SupraMeatal approach.

* Significant at the p = 0.05 level.

Table 2. Mann–Whitney U-tests between age-at-implantation groups on raw CVC(A) scores.

	U	z	p	r
Group comparisons (using Mann–Whitney U-tests)
Group 1 (6–12 months) vs. group 3 (19–24 months)	9.50	−3.09	0.001*	0.69
Group 1 (6–12 months) vs. group 4 (25–30 months)	1.00	−3.88	<0.001*	0.83
Group 1 (6–12 months) vs. group 5 (31–36 months)	0.00	−3.71	<0.001*	0.85
Group 2 (13–18 months) vs. group 5 (31–36 months)	5.00	−3.54	<0.001*	0.77
Group 3 (19–24 months) vs. group 5 (31–36 months)	14.00	−2.90	0.003*	0.63

CVC: consonant–vowel–consonant.

* Significant at the p = 0.005 level.

Table 3. Report of Spearman's rho correlation among variables.

	CVC score five years FU [%]	Ceiling	Age at CI surgery	Hearing loss level (ABR)	Hearing loss aetiology	Comorbidity	Prematurity	CI device	CI technique	Unilateral vs. bilateral CI at five years FU
N	54	54	54	54	54	54	54	54	54	54
Ceiling CVC(A)-score
ρ	0.78**
p (two-tailed)	<0.001
Age at CI surgery
ρ	−0.77**	−0.64**
p (two-tailed)	<0.001	<0.001
ABR hearing loss
ρ	−0.47**	−0.28*	0.45**
p (two-tailed)	<0.001	0.038	0.001
Aetiology
ρ	0.22	0.069	−0.14	−0.26
p (two-tailed)	0.11	0.62	0.30	0.059
Comorbidity
ρ	−0.058	−0.055	0.35**	0.14	0.10
p (two-tailed)	0.68	0.69	0.009	0.33	0.46
Prematurity
ρ	0.12	0.087	0.13	0.058	0.28*	0.37**
p (two-tailed)	0.37	0.53	0.37	0.68	0.044	0.006
CI device
ρ	0.68**	0.62**	−0.68**	−0.24	0.14	−0.21	0.023
p (two-tailed)	<0.001	<0.001	<0.001	0.087	0.33	0.14	0.87
CI technique
ρ	0.22	0.31*	−0.20	−0.17	0.15	0.25	0.16	0.24
p (two-tailed)	0.11	0.023	0.15	0.23	0.27	0.068	0.26	0.084
Unilateral vs. bilateral CI  at five years FU
ρ	0.56**	0.48**	−0.42**	−0.17	0.22	−0.038	−0.19	0.53**	0.18
p (two-tailed)	<0.001	<0.001	0.002	0.23	0.11	0.79	0.17	<0.001	0.19
Age at FU five years after CI
ρ	−0.76**	−0.65**	0.93**	0.31*	−0.049	0.33*	0.11	−0.75**	−0.25	−0.50**
p (2-tailed)	<0.001	<0.001	<0.001	0.024	0.72	0.014	0.42	<0.001	0.067	<0.001

Results marked in bold show a strong correlation (p < 0.01).

* Correlation is significant at the p = 0.05 level (two-tailed).

** Correlation is significant at the p = 0.01 level (two-tailed).

Figure 1. Proportion of children from each age-at-implantation group reaching the CVC(A) ceiling score at five-year follow-up. Error bars represent the 95% confidence interval. Between-groups analysis using Fisher exact test confirmed performance differences between group 1 and 4 (p < 0.001), group 1 and 5 (p < 0.001) and group 2 and 4 (p < 0.001) following Bonferroni correction.

Table 4. Report of results of binominal logistic regression analysis.

	β	Standard error	Wald	df	p	Exp (β)
Age at CI surgery	−3.25	1.41	5.33	1	0.021*	0.039
CI device	0.65	0.35	3.39	1	0.066	1.91
Unilateral vs. bilateral CI at five years FU	1.31	1.06	1.54	1	0.21	3.72
Comorbidity	2.02	1.83	1.22	1	0.27	7.57
hearing loss level (ABR)	−0.062	0.085	0.53	1	0.46	0.94
(Constant)	4.90	7.75	0.40	1	0.53	134.13

In this model age at implantation was the only significant predictor for reaching the five-year CVC(A) ceiling score (p = .021).

* Significant at the p = 0.05 level.