Neurology -- Correspondence for Ashwal et al., 62 (6) 851-863

Correspondence published:

Practice Parameter: Diagnostic assessment of the child with cerebral palsy: Jonathan W. Mink, MD, PhD, Mary E. Jenkins, MD (19 June 2004)

Practice Parameter: Diagnostic assessment of the child with cerebral palsy: M.A. Whelan, MD, PhD (19 June 2004)

Reply to Jenkins and Mink and Whelan: Stephen Ashwal, MD, Barry Russman, MD, Co-author, Oregon Health and Science University, Portland, OR (19 June 2004)

Practice Parameter: Diagnostic assessment of the child with cerebral palsy 19 June 2004

Jonathan W. Mink, MD, PhD,
Dept. of Neurology, University of Rochester
601 Elmwood Ave., Box 673, Rochester, NY,
Mary E. Jenkins, MD
Send Correspondence to journal:
Re: Practice Parameter: Diagnostic assessment of the child with cerebral palsy

Email Jonathan W. Mink, MD, PhD, et al.

We read with interest the recent article by Ashwal et al. [1] The Practice Parameter represents a thorough review of the current literature on an important issue that has diagnostic, prognostic, management and research implications. We view the final recommendations as clinically sound and feasible. However, we were struck by the paucity of evidence supporting these recommendations.
The guidelines focused on MRI and CT as a method of determining both etiology of cerebral palsy and timing of the lesion (Level A, class I evidence). There are five class I references 2-6 that evaluate neuroimaging in children with CP. The evidence from these studies support the recommendation that neuroimaging in conjunction with clinical history may determine etiology of cerebral palsy in many children.
The recommendations suggest that timing of the cerebral injury may be determined by CT or MRI imaging (Level A, class I evidence). This recommendation does not seem to be supported by the evidence. In Table 3 and Table 4 of the guidelines, the original references are listed with classification of cases based on CT or MRI into 1) prenatal, 2) perinatal and 3) postnatal events. In all four of the original class I studies 2, 3, 5, 6, the etiologies are determined to be either 1) prenatal or 2) prenatal / perinatal. There are no data from any of the class I studies that support the premise that an isolated perinatal etiology can be determined from neuroimaging.
Recommendations on evaluation of metabolic, genetic and coagulation studies are reported to be Level B and Level C. However, the evidence does not support this level of recommendation. The authors clearly state that no prospective studies have evaluated these issues. The studies cited concern the incidence of different etiologies and any diagnostic studies are small series or case reports, making the recommendations Level U.
The evidence reviewed in this paper is worthwhile and informative. However, the current literature is not adequate to develop Practice Parameters in this area. We question whether the American Academy of Neurology should be endorsing Practice Parameters on topics with such weak evidentiary support. We agree that the role of imaging in the diagnosis of disorders presenting as cerebral palsy is an important question in need of further research. However, a goal of a Practice Parameter should be to set evidence-based guidelines rather than to illustrate the need for additional research.
References
1. Ashwal S, Russman BS, Blasco PA, et al. Practice Parameter: Diagnostic assessment of the child with cerebral palsy: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2004; 62:851-63.
2. Wiklund LM, Uvebrant P, Flodmark O. Computed tomography as an adjunct in etiological analysis of hemiplegic cerebral palsy. I: Children born preterm. Neuropediatrics 1991; 22:50-6.
3. Wiklund LM, Uvebrant P, Flodmark O. Computed tomography as an adjunct in etiological analysis of hemiplegic cerebral palsy; II: Children born at term. Neuropediatrics 1991; 22:121-8.
4. Miller G, Cala LA. Ataxic cerebral palsy--clinico-radiologic correlations. Neuropediatrics 1989; 20:84-9.
5. Krageloh-Mann I, Petersen D, Hagberg G, Vollmer B, Hagberg B, Michaelis R. Bilateral spastic cerebral palsy--MRI pathology and origin. Analysis from a representative series of 56 cases. Dev Med Child Neurol 1995; 37:379-97.
6. Yin R, Reddihough D, Ditchfield M, Collins K. Magnetic resonance imaging findings in cerebral palsy. J Paediatr Child Health 2000; 36:139- 44.

Practice Parameter: Diagnostic assessment of the child with cerebral palsy 19 June 2004

M.A. Whelan, MD, PhD,
Neurologist
122 Sugar Hill Road, Cooperstown, New York 13326
Send Correspondence to journal:
Re: Practice Parameter: Diagnostic assessment of the child with cerebral palsy

mawhelan{at}capital.net M.A. Whelan, MD, PhD

The recent Practice Parameter on the diagnostic assessment of the child with cerebral palsy [1] presents findings and recommendations based upon a re-working of the usual standards of classification of evidence. The reclassification appears to have been undertaken to fortify the strength of the presented studies. Thus, articles formerly classified as Class III or IV, according to the usual AAN criteria, are now presented as Class I evidence (authors' references 6, 7, 8, 15,16).
However, the studies remain what they are - studies of selected, not representative, groups of patients. Figures for the percentages of abnormalities found on imaging studies, and of the co- morbidity of epilepsy, are unduly inflated as a result. Some co- morbidities, such as visual impairment (which relies on a definition of legal blindness not specified in the text) may be under-estimated.
Internally, there are also inconsistent classifications - a studied classified as Class III in Table 3 is promoted to Class II in the text (authors' reference 10), and studies identified as Class I are mis- matched to both old and new definitions of this evidence (authors' references 6,7,8,15,16,39,47). One study is actually a review article (authors' reference 47).
The re-worked classification scheme is also intrinsically unsatisfactory. The idea of a classification "appropriate only when the diagnostic accuracy of the fact or intervention is known to be good" does not stand up to scrutiny, nor do the artifices of the revised definitions of "population" or "statistical".

Current pre-publication review processes continue to need improvement, and systematic and authoritative statistical and epidemiological consultation should be an intrinsic part of the generation of parameters.
References
1. Ashwal S, Russman B.S., Blasco P.A. et al. Practice Parameter: Diagnostic assessment of the child with cerebral palsy. Neurology 2004;62:851-862.

Reply to Jenkins and Mink and Whelan 19 June 2004

Stephen Ashwal, MD,
Dept. of Pediatrics, Loma Linda University
11175 Campus Street, Loma Linda, CA 92350,
Barry Russman, MD, Co-author, Oregon Health and Science University, Portland, OR
Send Correspondence to journal:
Re: Reply to Jenkins and Mink and Whelan

sashwal{at}ahs.llumc.edu Stephen Ashwal, MD, et al.

We appreciate the comments of Drs. Jenkins and Mink and Dr. Whelan. We agree that there is limited evidence available concerning diagnostic information related to evaluating the child with cerebral palsy. However, based on the currently used classification scheme and linkage of evidence to recommendations, all of the proposed recommendations met criteria accepted by the Quality Standards Subcommittee of the American Academy of Neurology.
We also believe that we were able to extract, as best as possible, sufficient data to try to separate prenatal, perinatal and postnatal etiologies. This was difficult as, in some of the reports, there clearly was overlap; a phenomenon that all of us see in clinical practice. The same can be said for trying to extract data regarding the yield of metabolic and genetic studies.
We disagree with some of the comments of Dr. Whelan concerning using the recently developed classification scheme developed for screening evaluation. Unfortunately, there are no usual standards for the classification of diagnostic evidence. The diagnostic classification scheme previously developed by the QSS was not relevant to the clinical questions posed in this parameter. The purpose of this parameter was not to determine how accurately specific tests diagnosed conditions that cause cerebral palsy (e.g. the accuracy of MRI in identifying perinatal infarcts). Rather, the purpose was to determine how often specific tests identified the likely cause of cerebral palsy (e.g. the yield of MRI).
We agree with Dr. Whelan that for this type of clinical question, the key issue is whether the study patients are representative. The majority of studies were retrospective and likely were not completely representative of the population and as such were downgraded as to quality of the level of evidence. Essential design elements to determine how likely study patients are representative include the sampling method and sampling frame, hence the new scheme�s emphasis on population-based, statistical sampling. We do wish there was more evidentiary support for such guidelines but feel we did not overstep any recommendations.
We believe Dr. Whelan is in error with her comments concerning reference 10 as cited as class III evidence in table III and as class II evidence in the text�it is consistently cited as class III evidence. We also used reference 47, the article by the late Dr. Sheila Wallace, because it did review many studies that addressed topics covered in this parameter and was used as �background� material�it was not included in any of the evidence tables or used as a basis to make recommendations.
We feel that these guidelines are helpful as an initial step and do hope that, as the recommendations suggest, in the future research section of the parameter, that such recommendations will receive institutional and governmental support to support these much needed studies. We feel that the present parameter serves a very useful function and anticipate that one in another five years will even be more helpful.