StephenAshwal, MD, Dept. of Pediatrics, Loma Linda University
Published June 19, 2004
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.
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.