Impact of auditory variables on consonant production in babbling and early speech in children with moderate hearing loss - a longitudinal study.

This longitudinal study aimed to investigate early consonant production and the impact of hearing aid (HA) use, and aided audibility in Swedish children with moderate hearing loss (CHL) who received amplification before 6 months of age. CHL (n = 11) and children with normal hearing (CNH) (n = 11) were followed-up at 10, 18, and 36 months of age. At 10 months of age, the CHL used significantly fewer oral stops (p < 0.01), dental/alveolar stops (p < 0.05) and had a significantly fewer number of different true consonants (p < 0.01). At 18 months, there were no significant differences between the groups regarding presence of oral stops, and dental/alveolar stops, but the significant difference in the number of different true consonants remained (p < 0.00). At 36 months of age, consonant proficiency did not differ between the groups. A higher number of hours of HA use was associated with the presence of consonant variables at 10 months. Aided audibility showed weak to moderate correlations with number of consonants produced and proficiency. This group of children presented with initial delays in their early consonant production but seemed to catch up as they aged. Consistency of HA use from initial fitting is an important factor that may decrease the possible delays in the development of early consonant production and proficiency in CHL by 36 months of age.