Table 5 Multivariate linear regression of language test score (years) (postoperative)

Age of hearing loss (months)

4.8 ± (1.9)

0.02 (− 0.04 to 0.08, p = 0.494)

 − 0.09 (− 0.19 to 0.01, p = 0.063)

Cause of hearing loss

 Meningitis

5.0 ± (3.2)

-

-

 Otitis media

2.8 ± ( −)

 − 2.25 (− 7.18 to 2.68, p = 0.358)

 − 1.85 (− 6.80 to 3.11, p = 0.446)

 Unknown

4.8 ± (1.9)

 − 0.15 (− 3.09 to 2.79, p = 0.918)

 − 2.02 (− 5.50 to 1.45, p = 0.239)

Age of hearing aids fitting (months)

4.9 ± (1.9)

 − 0.03 (− 0.16 to 0.09, p = 0.565)

 − 0.03 (− 0.16 to 0.09, p = 0.565)

Duration of hearing deprivation till hearing aids (months)

4.8 ± (1.9)

 − 0.04 (− 0.19 to 0.10, p = 0.540)

 − 0.08 (− 0.25 to 0.09, p = 0.347)

Duration of hearing depravation from hearing loss till CI (years)

4.8 ± (1.9)

0.11 (− 0.24 to 0.46, p = 0.533)

 − 0.20 (− 0.63 to 0.23, i = 0.345)

Duration of rehabilitation in years (preoperative)

5.0 ± (1.9)

0.08 (− 0.17 to 0.32, p = 0.534)

0.08 (− 0.17 to 0.32, p = 0.534)

Age of operation cochlear implantation CI (years)

  [0.58,7]

4.8 ± (1.9)

0.57 (0.18 to 0.96, p = 0.006)

1.05 (0.22 to 1.87, p = 0.016*)

Implant brand

 Cochlear

4.7 ± (2.3)

-

-

 MED-EL

5.0 ± (1.8)

0.28 (− 1.48 to 2.03, p = 0.750)

 − 0.45 (− 2.52 to 1.63, p = 0.659)

 Oticon

4.8 ± (2.6)

0.07 (− 2.72 to 2.86, p = 0.959)

 − 1.32 (− 4.42 to 1.79, p = 0.387)

Site of insertion

 Boney cochleostomy

5.1 ± (1.9)

-

-

 Extended round window

5.1 ± (1.7)

0.07 (− 1.63 to 1.77, p = 0.936)

 − 0.59 (− 2.50 to 1.32, p = 0.528)

Round window

4.1 ± (2.2)

 − 0.97 (− 2.62 to 0.67, p = 0.238)

 − 0.76 (− 3.06 to 1.53, p = 0.495)

Parents’ involvement

Negative

5.2 ± (1.8)

-

-

Positive

4.7 ± (2.0)

 − 0.52 (− 2.14 to 1.11, p = 0.520)

 − 0.28 (− 2.20 to 1.63, p = 0.760)