یک تحقیق تجربی از تاثیر برنامه لیدکامب در لکنت زبان زودرس

Preliminary Phase I and II trials for the Lidcombe Program of early stuttering intervention have found favorable outcomes and that the treatment is safe. Although speech–language pathologists (SLPs) often need to intervene with pre-schoolers’ early stuttering, many of these children will recover at some time in the future without such intervention. Consequently, they need to know whether the Lidcombe Program’s effect on stuttering is greater than that of natural recovery. Participants were 23 pre-school children who were randomly assigned to either a control group or a treatment group that received the Lidcombe Program for 12 weeks. A repeated measures ANOVA showed no main effect on stuttering for the group (control/treatment), a significant main effect for the measurement occasion (at the start and at the end of the treatment period), and a significant interaction between group and measurement occasion. Stuttering in the treatment group reduced twice as much as in the control group. These results are interpreted to mean that the introduction of the Lidcombe Program has a positive impact on stuttering rate, which exceeds that attributable to natural recovery.

The Lidcombe Program is a behavioral treatment for stuttering in pre-school-age children. The treatment is conducted by parents in the child’s everyday environment and parents learn how to do the treatment during the weekly visits with the child to the speech–language pathologist (SLP). A comprehensive description of the Lidcombe Program can be found in Onslow, Packman, & Harrison (in press). In the Lidcombe Program, the parent gives verbal contingencies during conversational exchanges with the child. These verbal contingencies are directed at: (1) stutter-free speech; (2) unambiguous stuttering; (3) correct self-evaluation of stutter-free speech; and (4) spontaneous self-correction of stuttering. These verbal contingencies consist of: (1) acknowledgment and/or praise for periods of stutter-free speech; (2) acknowledgment of stuttering and/or a request that the child corrects stuttering; (3) praise for correct self-evaluation of stutter-free speech; and (4) praise for spontaneous self-correction of stuttering. The SLP ensures that these parental verbal contingencies are not constant, intensive or invasive, and that parents are at all times positive and supportive of the child receiving the treatment. The treatment is individualized for each family and, as with any treatment for a childhood speech or language disorder, it is essential that the child enjoys the treatment and finds it to be a positive experience. Stuttering measures are an essential component of the Lidcombe Program. The parent makes daily measures of the severity of the child’s stuttering on a 10-point scale, where 1 = no stuttering; 2 = very mild stuttering; and 10 = extremely severe stuttering. The SLP makes weekly measures of stuttering rate (percent syllables stuttered, %SS). Together, these two measures are used to: (1) guide implementation of the program from week to week; (2) identify when the child has met criterion speech performance; and (3) check that the child’s speech continues to meet criterion speech performance in the long-term. The stuttering measures also enable the SLP and the parent to communicate effectively about the severity of the child’s stuttering throughout the treatment process. The Lidcombe Program is conducted in two stages. Stage 1 is complete when the child’s stuttering is below 1.0%SS and each of the daily severity ratings for the corresponding week are either 1 or 2, with the majority being 1. During Stage 2, the parent gradually withdraws the verbal contingencies and gradually assumes complete responsibility for the treatment as visits to the clinic decrease in frequency. Any departure from the criterion speech performance, as specified with the stuttering measures at the end of Stage 1, results in more frequent clinic visits and possibly an increase in parental contingencies. A file audit of 250 children treated with the Lidcombe Program (Jones, Onslow, Harrison, & Packman, 2000) showed that the mean number of weekly clinic visits taken to complete Stage 1 was 12.5, and a recovery plot for these children showed that 90% of them had completed Stage 1 after 22 clinic visits. Jones et al. found that pre-treatment stuttering rate was the only predictor of time required to complete Stage 1. Other case variables — most notably time since reported onset — did not affect the time taken to complete Stage 1. The safety and clinical promise of the Lidcombe Program have been established in Phase I and II (Pocock, 1996) trials. Non-controlled trial data (Onslow et al., 1994 and Onslow et al., 1990) and file audit data (Jones, Onslow, Harrison, & Packman, 2000) have shown outcomes of zero or near zero rates of stuttering in children in the medium-term after treatment with the Lidcombe Program. Long-term data on 42 children (Lincoln & Onslow, 1997) show outcome to be durable. The social validity of treatment outcomes has been established (Lincoln, Onslow, & Reed, 1997). Given that the Lidcombe Program is a direct treatment, it is perhaps not surprising that concerns have been expressed about its safety (Cook, 1996; Cook & Rustin, 1997). Consequently, Woods, Shearsby, Onslow, and Burnham (2002) demonstrated that the treatment was not associated with psychological harm to children. To date, however, the efficacy of the Lidcombe Program has not been established. In other words, there is no unequivocal evidence that the reductions in stuttering that occur with the Lidcombe Program are in fact due to the treatment. The most important issue to consider in determining the effectiveness of treatments for early stuttering is, of course, natural recovery. Here, there are two questions (Packman & Onslow, 1998). The first is whether recovery from stuttering with the Lidcombe Program is greater than natural recovery in the long-term. In other words, after a clinically significant post-treatment period, are the improvements in stuttering that occur after treatment with the Lidcombe Program greater than those of natural recovery? The definitive answer to this question would involve comparing a group of children who receive no treatment with a group of children who receive treatment with the Lidcombe Program. In light of the fact that natural recovery may take 2 years or longer (e.g., Ingham & Riley, 1998; Yairi & Ambrose, 1999), this would involve withholding treatment for a control group of children for a number of years. This cannot be justified on ethical grounds, so the next best thing is to compare the Lidcombe Program with another treatment or treatments. Consequently, a Phase III ( Pocock, 1996) randomized controlled trial of the program is in progress in New Zealand ( Jones, Gebski, Onslow, & Packman, 2001). A second, and equally important question about effectiveness concerns the immediate effects of this treatment: When the Lidcombe Program is introduced, are its effects on the course of the disorder greater than the effects of natural recovery? Natural recovery occurs in many cases of early stuttering, with two recent estimates lying in the mid-70% range ( Mansson, 2000; Yairi & Ambrose, 1999). At present, however, there is some doubt that recovery rates for children who present to a clinic would be as high as those population estimates. In any event, in many instances SLPs will want to implement treatment sometime during the pre-school years, despite not knowing whether the child is destined to recover naturally. There are many reasons for clinicians to treat a pre-school child who stutters, even though there is a chance that natural recovery may occur at some future time ( Packman & Onslow, 1999; Packman, Onslow, & Attanasio, in press). Consequently, there is need for evidence that the immediate reductions in stuttering observed with the Lidcombe Program can be attributed primarily to the treatment rather than to natural recovery. An experimental design is required to establish this evidence. Such a design involves withholding treatment for a control group, but only for a short period, and would determine whether the Lidcombe Program provides short-term benefits beyond what might be expected from natural recovery. The present paper reports such an experimental investigation. In this study, a group of children who receive the Lidcombe Program over 12 clinic visits is compared with a control group of children who receive no treatment for 12 weeks. Twelve clinic visits was chosen as this is close to the mean number of clinic visits (12.5) taken by pre-school children to complete Stage 1 of the Lidcombe Program (see earlier). Of course, not all children receiving the Lidcombe Program in the study would be expected to complete Stage 1 within 12 clinic visits, but this was considered a sufficient period to demonstrate the impact of the treatment on the natural course of stuttering.