Table 4.
Individual study characteristics
| Study | CI group n | NH group n | Matching variables | Focus of study | Mean age CI group (months) | Mean age at CI activation | Bilateral versus unilateral CI | Vocabulary measure(s) | Construct measured |
|---|---|---|---|---|---|---|---|---|---|
| Ambrose et al. (2012) | 24 | 23 | Maternal education, age, geography | Early literacy skills | 49.46 | 20.96 | 11/13 | PPVT-4 | Receptive |
| Boons et al. (2013) | 70 | 70 | Gender, age, geography, SES | Vocabulary, grammar | 86 | 20 | 27/43 | EOWPVT | Expressive |
| Caldwell et al. (2013) | 27 | 19 | Age, geography, SES | Speech perception | 81 | 21 | 18/9 | EOWPVT | Expressive |
| Caselli et al. (2012) | 17 | 17 | Age, geography, SES, maternal education | Vocabulary, grammar | 54 | 16 | 9/8 | LPT | Receptive and expressive |
| Davidson et al. (2014) | 101 | 47 | Age, geography, SES | Word learning, vocabulary | 107.52 | 24.6 | 53/47 | PPVT-3 | Receptive |
| Dillon et al. (2011) | 27 | Norm | N/A | Phonological awareness, reading, vocabulary | 109.2 | 30 | Not reported | PPVT-3 | Receptive |
| Fagan and Pisoni (2010) | 23 | Norm | N/A | Vocabulary | 109.2 | 30 | Not reported | PPVT-3 | Receptive |
| Geers et al. (2009) | 153 | Norm | N/A | Spoken language | 70 | 28 | PPVT-3; ROWPVT; EVT-2; EOWPVT | Receptive and expressive | |
| Geers and Nicholas (2013) | 60 | Norm | N/A | Spoken language | 126 | 22.7 | 29/31 | PPVT-3; EOWPVT | Receptive and expressive |
| Johnson et al. (2010) | 39 | 19 | Geography, reading ability | Phonological awareness, vocabulary | 121.5 | 46.5 | Not reported | BPVS; EOWPVT | Receptive and expressive |
| Lofkvist et al. (2014) | 34 | 39 | Gender, age, geography, cognition | Vocabulary | 92 | 22 | 33/1 | PPVT-3 (Swedish version) | Receptive |
| Luckhurst et al. (2013) | 9 | 42 | Gender, age, geography, ethnicity, SES | Vocabulary | 58.3 | 19.2 | 6/3 | PPVT-4; EVT-2 | Receptive and expressive |
| Nittrouer et al. (2014) | 55 | 49 | Age, gender, SES, cognition | Nonword repetition | 103 | 20 | 28/27 | EOWPVT | Expressive |
| Sarant and Garrard (2014) | 70 | Norm | N/A | Parenting stress, language | 79.2 | 18.6 | 54/16 | PPVT-4 | Receptive |
| Schorr et al. (2008) | 39 | 37 | Gender, age, cognition, SES | Vocabulary, grammar | 108 | 35.64 | Not reported | PPVT-3; EVT | Receptive and expressive |
| Walker et al. (2013) | 24 | 24 | Age, geography, maternal education, cognition | Word learning | 58.32 | 20.16 | 13/11 | PPVT-3 | Receptive |
Note. CI = cochlear implant; NH = normal hearing; norm = used norm-referenced comparison; SES = socioeconomic status; BPVS = British Picture Vocabulary Scale (Dunn, Dunn, Wheton, & Pintilie, 1997); EOWPVT = Expressive One-Word Picture Vocabulary Test (Brownell, 2000a, 2000b); EVT = Expressive Vocabulary Test (Williams, 2007); LPT = Lexical Phonological Test (Vicari, Marotta, & Luci, 2007); PPVT-3 = Peabody Picture Vocabulary Test, Third Edition (Dunn & Dunn, 2007); PPVT-4 = Peabody Picture Vocabulary Test, Fourth Edition (Dunn & Dunn, 2007); ROWPVT = Receptive One Word Picture Vocabulary Test (Brownell, 2000a, 2000b).