'Neurodevelopmental treatment for cerebral palsy: is it effective?'

‘Neurodevelopmental treatment for cerebral palsy: is it effective?’ SIR–We appreciate this opportunity to respond to the article by Charlene Butler and Darrah, ‘Effects of neurodevelopmental treatment (NDT) for cerebral palsy: an AACPDM evidence report’.1 We also acknowledge the time and effort that the Academy has put into compiling research related to NDT; an important area of therapeutic practice. However, we were concerned that the report had methodological limitations as well limitations in its approach to evaluating evidence for the effectiveness of NDT in children with cerebral palsy (CP). We stress that it would be premature and mistaken to conclude that NDT is not beneficial. Absence of evidence of effectiveness in an evidence report cannot be construed as proof that a treatment is not effective. Rather, it may reflect areas in which more meaningful research is needed. To assess accurately the effectiveness of NDT in CP there needs to be consistent operational definitions of both NDT and CP. It is important to remember that NDT has evolved and changed. For example, the evidence review stated that originally, NDT advocated placing children in reflex inhibiting postures. This is no longer practiced. Yet the evidence report included early articles on such abandoned practices as evidence that NDT is not effective. We point out that the reviewers compared studies published before 1990 with those published between 1990 and 2000 and found the more recent results favored NDT, especially in the areas of motor impairment and motor activity measures. However, this information was not included in their summary. The reviewers also included articles that may not have used NDT per se. They cited articles that described procedures that specified inhibition of primitive responses and pathological reflexes but were not stated to be NDT. It is unfair to the NDT approach to suggest that an article that did not specify that NDT was utilized constitutes valid evidence that NDT is ineffective. There are many obstacles that make it difficult, if not impossible, to answer the research question: ‘Is NDT effective for CP?’ First, NDT is not a ‘treatment’ for CP. It is an approach used to assess and to assist children with CP to perform functional tasks sooner and better and with minimal negative effect on future functional abilities. Second, CP is as broad and heterogeneous as its management is challenging. Children with CP include children with spastic diplegia, spastic quadriplegia, ataxia, and athetoid movements. When studying treatment of the disorder, it is hard to recruit a homogeneous population, harder to recruit one of ample size, and nearly impossible to recruit a study population with homogeneous functional goals. Third, identifying and measuring outcomes that can test whether NDT is effective is difficult. Scores on Denver Developmental Screening Tests or the Bayley Motor Scales are examples of measures of function used in the cited studies. These scales are not sensitive to the types of outcomes expected when using an NDT intervention. NDT focuses on discrete and individual functional needs of involved children and not developmental milestones. For example, a child treated with NDT who has feeding problems may benefit from an individualized plan to improve her feeding capability. While the treatment may reduce the danger of aspiration and improve the child’s current nutritional state, it would be inappropriate to expect that such treatment will improve the child’s performance on the Bayley Motor Scale. Because of these difficulties, we are pleased that the AACPDM is accepting the methodology of single-subject research design as a valid, evidence-based form of research. Other than ‘n-of-1 studies’, we were unaware of levels of efficacy for single subject research design and applaud the AACPDM for seeing a need in the area of rehabilitation research. It would be interesting to open up the discussion of whether the scientific community as a whole accepts categorizing singlesubject research design evidence according to the AACPDM’s ranking. We suspect that trying to evaluate the effectiveness of NDT for CP, as was done in this report, is neither useful nor appropriate. We stress that NDT is a method of assessing diverse, neurologically impaired children, identifying their functional state and needs, planning and, yes, treating the child to facilitate meeting those needs. Consequently, focusing on levels of evidence as to NDT’s effectiveness may not be warranted. Can we design a level 1 or level 2 study to research the efficacy of a complex, multifaceted assessment as well as treatment approach? To ask if such an approach ‘works’ strikes us as analogous to asking, ‘Does the neurologist’s approach work to ameliorate CP?’ The immediate answer is no, because neurologists do not cure CNS dysfunction. A better question might be: ‘Does the neurologist assist children with CP to be more functional?’ This is a more appropriate question, but still too global and multifaceted. However, if one were to define operationally an aspect of the clinicians’ intervention and appropriately define children with specific and well-delineated impairments, as well as have functional outcomes, then research would be possible. It necessitates asking many questions about specific techniques for specific impairments of children with CP working toward specific functional goals. We have reservations about whether the conclusions reached by the reviewers are justified. For example, the Adams2 article is identified as one of the studies reviewed, but then it is left out of evidence Table VI and not cited as a study that demonstrated functional gains associated with NDT. Also, articles with results that suggested benefit from NDT that did not reach statistical significance were analyzed as though they were the same as articles where the results favored the control treatments. This is a bias in analysis that fails to recognize the likelihood that such studies favorable to NDT might contain type II errors and thus fail to demonstrate the superiority of NDT because the sample size was too small to achieve statistical significance. For example, the evidence review states under the heading Societal Limitation/Context Factors: ‘Only one of 14 results supports the expectation that NDT would confer a greater benefit to maternal–child interaction’. It would have been more factual to say:‘Only one of two studies supports the expectation that NDT would confer a greater benefit to maternal–child interaction; the other study did not show a statistically significant benefit’. Using the AACPDM method, it would be as appropriate to say that the Palmer’s study 3 supports NDT in relation to maternal–child interaction (responsiveness and involvement) because their results were positive, but not statistically significant. Yet, these results were listed as part