Communication Disorders and Scientific Method: A Cautionary Tale (1981)
From the SAC Archives: A Year-Long Retrospective Series
Publication: Hear Here, Volume V, Number 1
Original publication date: February 1981
Author: John H.V. Gilbert
Introduction by: Sharon Halldorson, S-LP(C) and Maureen Penko, S-LP(C)
John Gilbert’s 1981 article “Rumination” in Hear Here provides a fresh reminder that we need to proceed with caution regarding our testing. Gilbert illustrates his concerns using the example of auditory processing, which was relatively new in the 1980s. In spite of considerable brain research since that time, Gilbert’s caution remains highly relevant today. He reminds us that “One of the problems (and therefore a pitfall) of clinical life is that peers, clients and other professions are constantly seeking a yardstick for diagnosis, prognosis and treatment. Without an appreciation of the limitations in the appropriate scientific theory and data, the tools available for providing such a yardstick are of little or no value.” This message is so important for us to remember. As professionals, we must always rely on our clinical judgement (based on our experience and knowledge of individual clients) over test results. It is what we do with the data — formal and informal — that allows us to plan effective and well-designed interventions. Gilbert writes a very important cautionary tale that is still worth consideration in 2014.
Rumination
The past ten years have seen an almost exponential increase in the number and variety of tests with which to determine the range and scope of a communication disorder. These tests purport to examine (against some norm) every functional part of the speech chain, i.e. from the brain to the tongue. A similar, but not as vigorous, growth has occurred in the various ‘’therapies” which might be applied to a disorder : from the fanciest electroacoustics for the damaged cochlea to the most elaborate elaborations of generative grammars/pragmatics for the “damaged” brain. In one sense, such empirical overkill might be viewed with pride, demonstrating as it does, that Audiology and Speech-Language Pathology are concerned with quantifying their diagnostic and therapeutic decision-making actions. In another sense, however, such rampant empiricism engenders qualms as one views the ways in which the very narrow data-base of psychoacoustics, speech perception and linguistics is being used without full acknowledgement of their present limitations.
Audiology and Speech-Language Pathology need constant reiteration of its scientific bases. When theories and tests are based on correlations about the speech chain which are assumed to be causal, then the profession finds itself in serious difficulties.
Today, for example, tests of language perception (whatever that may be) are being (and have been) developed to help the clinician identify those abilities felt necessary for the processing of language. Once identified, such abilities may then in some sense be channelled in the right direction (perhaps even using the test) for language processing.
But the truth is that for the most part we do not know either what language processing is, or how it comes about. The theoretical base on which instruments for testing such abilities are developed is either very weak or at best, highly controversial. Terms such as “auditory memory span”, “auditory discrimination”, “perceptual deficit”, etc., are empty phrases when one considers that we as yet are unable to even satisfactorily separate phonetic from auditory perception, or whether either has anything to do with language.
Of the various stages of language analysis generally agreed upon, i.e. auditory, phonetic, phonological, lexical, syntactic and semantic, everything beyond the auditory stage is abstract, i.e. each stage demands that we recognize some property which is not present in the auditory signal. Thus, when we listen to speech we cannot expect the first stage (auditory) to function independently of all the rest. Even the best guesses we have to date are insufficient to resolve some of the burning issues in speech perception. This being the case, we have to assume that anything which claims to “test” such abilities as “perception”, “discrimination”, etc. AND THEN ASCRIBE A CAUSE TO THE RESULTS, has taken a remarkably long and erroneous step away from present theories and data. One just cannot say, for example, that a child has a central auditory problem simply because she does “poorly” on a test of auditory discrimination.
I have chosen the area of speech perception to illustrate the point, because the cluster of testing and therapy techniques which involve it seem at the present time to be running unrestrained, and significantly at odds, with the realities of their scientific base.
One might as easily illustrate the point by focusing on hearing aids and our lack of knowledge vis-a-vis cochlear mechanisms. One of the problems (and therefore a pitfall) of clinical life is that peers, clients and other professions are constantly seeking a yardstick for diagnosis, prognosis and treatment. Without an appreciation of the limitations in the appropriate scientific theory and data, the tools available for providing such a yardstick are of little or no value. An assumption of causality, in the absence of informed consideration of reasonable alternative hypotheses, is in fact a misassumption. Unfortunately such misassumptions about causality are continuously drawn from so-called “tests” of this or that perceptual function.
A profession is only as good as its theories and their database : whether one works in clinic or laboratory, the constant application of scientific method to such theories and their data is the only sure way that we, as a profession, can progress.
About this retrospective series:
To commemorate SAC’s 50th anniversary, we will be republishing articles from SAC’s early newsletters and magazines throughout 2014. We will republish the articles in their entirety and will not be editing them for style or grammar. Sharon Halldorson, S-LP(C); Maureen Penko, S-LP(C); Andrea Richardson-Lipon, AuD, Aud(C) and Jessica Bedford, SAC Director of Communications and Marketing, are the editors of this year-long retrospective series.
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