Table 2

Characteristics and findings of the eligible studies that performed non-vestibular specific balance assessments

First author, year, country	Study design	N	N with hearing loss (HL)	Age (mean)	Mode of balance assessment	STROBE quality	Vision assessment	Findings
Alarcon, 2013, Spain26	M cohort	26 ScCMV	17 (severity not specified) CI use not reported	8.7 years	Movement ABC-2	Moderate	Not specified	27% (3 out of the 11 children without cerebral palsy) had borderline balance skills. 8% (2) had severe visual deficit – no further details available.
De Kegel, 2015, Belgium28	Case–control	26 ScCMV 38 AcCMV 107 cCMV negative controls	19 (ScCMV 83.2 dB; AcCMV 94.0 dB)* 9 using CI	24 months	Ghent Developmental Balance Test	Moderate–low	Not reported	Children with ScCMV and hearing impairment had significantly worse balance than controls and children with AcCMV.
Harris, 1984, USA25	P cohort	50 cCMV	5 (1 MI, 4 total) CI use not reported	3 months	Traction response test	Moderate–low	Ophthalmological examination	9% (4 out of 43) had transient head lag. No ophthalmological abnormalities found.
Korndewal, 2017, Netherlands27	R cohort	26 ScCMV 107 AcCMV	2 ScCMV 3 AcCMV (2 ears MO, 1 ear SE, 4 ears PR) CI use not reported	5 years, 6 months	Movement ABC Physical therapist report	Moderate	Ophthalmological examination. Optometrist examination.	6% (8) had balance impairment. 2.8% (3) AcCMV had visual impairment (1 unilateral optic nerve atrophy impairment, 2 cortical visual impairment).

Study design: R=retrospective, P=prospective, M=mixed (retrospective and prospective)
Hearing loss=severity reported where available.
Mode of balance assessment please see appendix A for glossary of vestibular and balance investigations.
Findings: (n)=number of cCMV cases out of N; where number of children tested is different to N, (n out of….) is reported.
*Where only mean decibel (dB) hearing threshold was reported, this can be interpreted as: <20 dB=normal; 21–40 dB=mild; 41–70 dB=moderate; 71–90 dB=severe; 91–119 dB=profound (Bernard, 2015).
ABC, assessment battery for children; AcCMV, asymptomatic cCMV; CI, cochlear implant; M, mixed (retrospective and prospective); MI, mild; MO, moderate; N, number of cCMV cases; P, prospective; PR, profound; r, Retrospective; ScCMV, symptomatic CMV; SE, severe; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology.