Non-pharmacological interventions for stuttering in children six years and younger (review)

Background
Stuttering, or stammering as it is referred to in some countries, affects a child's ability to speak fluently. It is a common communication disorder, affecting 11% of children by four years of age. Stuttering can be characterized by sound, part word or whole word repetitions, sound prolongations, or blocking of sounds or airflow. Moments of stuttering can also be accompanied by non‐verbal behaviours, including visible tension in the speaker's face, eye blinks or head nods. Stuttering can also negatively affect behavioural, social and emotional functioning.

Objectives
Primary objective

To assess the immediate and long‐term effects of non‐pharmacological interventions for stuttering on speech outcomes, communication attitudes, quality of life and potential adverse effects in children aged six years and younger.

Secondary objective

To describe the relationship between intervention effects and participant characteristics (i.e. child age, IQ, severity, sex and time since stuttering onset) at pretest.

Search methods
We searched CENTRAL, MEDLINE, Embase, PsycINFO, nine other databases and two trial registers on 16 September 2020, and Open Grey on 20 October 2020. There were no limits in regards to language, year of publication or type of publication. We also searched the reference lists of included studies and requested data on unpublished trials from authors of published studies. We handsearched conference proceedings and programmes from relevant conferences.

Selection criteria
We included randomized controlled trials (RCTs) and quasi‐RCTs that assessed non‐pharmacological interventions for stuttering in young children aged six years and younger. Eligible comparators were no intervention, wait list or management as usual.

Data collection and analysis
We used standard methodological procedures expected by Cochrane.

Main results
We identified four eligible RCTs, all of which compared the Lidcombe Program to a wait‐list control group. In total, 151 children aged between two and six years participated in the four included studies. In the Lidcombe Program, the parent and their child visit a speech and language therapist (SLT) in a clinic. One study conducted clinic visits by telephone. In each clinic visit, parents were taught how to conduct treatment at home. Two studies took place in Australia, one in New Zealand and one in Germany. Two studies were conducted for nine months, one for 16 weeks and one for 12 weeks. The frequency of clinic visits and practice sessions at home varied within the programme. One study was partially funded by the Rotary Club, Wiesbaden, Germany; and one was funded by the National Health and Medical Research Council of Australia. One study did not report funding sources and another reported that they did not receive any funding for the trial.

All four studies reported the outcome of stuttering frequency. One study also reported on speech efficiency, defined as articulation rate. No studies reported the other predetermined outcomes of this review, namely stuttering severity; communication attitudes; emotional, cognitive or psychosocial domains; or adverse effects.

The Lidcombe Program resulted in a lower stuttering frequency percentage syllables stuttered (% SS) than a wait‐list control group at post‐test, 12 weeks, 16 weeks and nine months postrandomization (mean difference (MD) −2.16, 95% confidence interval (CI) −3.48 to −0.84, 4 studies, 151 participants; P = 0.001; very low‐certainty evidence).

However, as the Lidcombe Program is designed to take one to two years to complete, none of the participants in these studies had finished the complete intervention programme at any of the data collection points.

We assessed stuttering frequency to have a high risk of overall bias due to high risk of bias in at least one domain within three of four included studies, and to have some concern of overall bias in the fourth, due to some concern in at least one domain.

We found moderate‐certainty evidence from one study showing that the Lidcombe Program may increase speech efficiency in young children.

Only one study reported outcomes at long‐term follow‐up. The long‐term effect of intervention could not be summarized, as the results for most of the children in the control group were missing. However, a within‐group comparison was performed between the mean % SS at randomization and the mean % SS at the time of extended follow‐up, and showed a significant reduction in frequency of stuttering.

Authors' conclusions
This systematic review indicates that the Lidcombe Program may result in lower stuttering frequency and higher speech efficiency than a wait‐list control group in children aged up to six years at post‐test. However, these results should be interpreted with caution due to the very low and moderate certainty of the evidence and the high risk of bias identified in the included studies. Thus, there is a need for further studies from independent researchers, to evaluate the immediate and long‐term effects of other non‐pharmacological interventions for stuttering compared to no intervention or a wait‐list control group.