Longitudinal study of factors relating to recovery from childhood stuttering

Investigations of factors relating to recovery from childhood stuttering are usually based on univariate analysis. Due to this, these factors may not be properly understood, because the relationship between a specific characteristic and recovery from stuttering may be confounded by other factors, or because the relationship between a characteristic and recovery may differ according to whether the subject possesses another factor concurrently. We conducted a longitudinal study of stuttering children who received treatment at stuttering treatment facilities and performed a multivariate analysis by sex and time from onset. We examined the associations between recovery and pre-treatment characteristics by following 97 stuttering children (average age at first consultation at a research institute, 55.7 months; range, 24-111 months) who received stuttering treatment from speech-language-hearing therapists in 14 stuttering treatment facilities. The average time from onset until recovery or end of observation was 36.0 months (range, 5-83 months). Characteristics associated with recovery from stuttering on univariate analysis were simultaneously entered into a proportional hazards model. In this model, stuttering developmental phase was identified as a factor independently related to recovery on analysis of all subjects and analysis by sex. On analysis by time from onset, pre-treatment characteristics were associated with recovery only in the group that received consultations at a stuttering treatment facility within 24 months of onset. An onset age of 24 months or earlier, female sex and a stuttering developmental phase of 1 were found to be associated with a high recovery rate in a mutually independent manner. The period when predictive factors of stuttering recovery can be observed is within 24 months of onset; prognosis for stuttering treatment begun within this time frame can be predicted based on onset age, sex, and pre-treatment developmental phase.