Welcome to the February 2012 issue of Plural Community, the free newsletter by your community, for your community.

This issue features a thought-provoking piece by ASHA Fellow, Robert Goldfarb, PhD, who writes on the complexities of diagnosis in communication disorders. (This writer often wondered why his chocolate ice cream often had a strong hint of banana – read on to make sense of this observation!)

Additionally, congratulations are extended to Patricia LaPierre from Stewart Manor, NY, who was the winner of our monthly competition for January and won a free copy of School Programs in Speech-Language Pathology: Organization and Service Delivery, Fifth Edition. Thanks to everyone who took the time and trouble to enter. We appreciate it, and wish you better luck next time. For details of this month’s competition, see below.

Lastly, please check out our list of new publications launching this month.

Thanks for reading on…

Case Studies

Dumping it in the Chocolate: Problems in Diagnosis

Robert Goldfarb, Ph.D.

A recent article in The New York Times reported a 40-fold increase in the number of American children and adolescents who were treated for bipolar disorder in the decade from 1994–2003. Almost certainly, the number has grown since then. There is little concern about the likelihood of a vast spike in the incidence of bipolar disorder, as the consensus is that doctors currently use the diagnosis more aggressively than before. The startling magnitude of the increase in diagnosis intensifies the debate over the validity and reliability of the criteria. If the term bipolar disorder is applied as a catchall for any child exhibiting explosive or aggressive behaviors, then far too many children are being treated with powerful psychoactive drugs with few demonstrable benefits and many potentially serious side effects.

The author supported himself through college by working in an ice cream factory. Occasionally, at the end of the workday there was excess ice cream mix. The next day’s run would start with chocolate, and the excess mix would be blended in. Chocolate was strong enough in flavor and color to absorb the leftover. Continuing the metaphor, overdiagnosis may occur when a particular classification is the “flavor of the month.”

The field of communication sciences and disorders is hardly exempt from faddish behavior in applying diagnostic labels. The term cluttering was widely used in the 1960s and 1970s to describe rapid-fire, indistinct speech with some word-finding difficulty and lack of awareness of difficulty by the speaker. The diagnosis has been virtually absent since then. It may be reviving currently, in part because of the new research efforts reported at an international conference on cluttering in Bulgaria in 2007 (Bakker, Raphael, & Myers, 2010).

Psycholinguistic Studies

Over the past 30 years, our research groups have developed linguistic tools to assist in the differential diagnosis of language disorders of adults with Alzheimer disease, vascular (frontotemporal) dementia, the language of schizophrenia, and various classifications of aphasia, as compared to control groups of typical young adults and typical elderly. The first group of studies, using word association of time-altered stimuli, tested semantic and syntactic hypotheses; the second group of studies of communicative responsibility and semantic tasks yielded semantic and pragmatic language data; and the third group of investigations of noun-verb ambiguity addressed neurolinguistic and psycholinguistic theories. Characteristic patterns of language and communicative behavior were noted for all groups; the discussion was on implications for clinical intervention.

Our research has proceeded from the premise that linguistic data can aid in the differentiation of diagnostically related groups. The following hypothetical case description illustrates the need for differential diagnosis:

  • An elderly homeless man, identified as Mr. X because he cannot say his name, has been admitted with what the emergency room physician described as “disorganized language.” The patient has no identification, no documented medical history, and has not yet had brain imaging studies. You have been asked to determine if the disorganized language represents fluent aphasia, the language of schizophrenia, or the language of dementia.
  • The patient is referred to a speech-language pathologist at University Hospital. Evaluation of Mr. X’s language reveals preservation of prosody, phonology, morphology, and syntax, with disturbances in semantics and pragmatics. This still fits the pattern of the diagnostically related groups of fluent aphasia, the language of Alzheimer and vascular dementia, and the language of chronic undifferentiated schizophrenia.

Neuroimaging Studies

The left perisylvian region has been classically described as the zone of language (see review by Code [2013]). Damage following occlusion or narrowing of the left middle cerebral artery (MCA) can independently cause language problems (aphasia), speech articulation disorders (apraxia of speech), and many other deficits. Medicinal, mechanical, and surgical techniques have all met with qualified success in resolving thromboembolic occlusions in the distribution of the MCA.

In 1996 the U.S. Food and Drug Administration (FDA) approved the use of tissue plasminogen activator (tPA) treatment for managing ischemic stroke within the first three hours of onset. Unfortunately, cerebrovascular accidents often occur during sleep hours, and the 3-hour window is missed. In addition, tPA treatment can be contraindicated when the stroke is hemorrhagic, where such intervention can have devastating consequences. Such an outcome received wide attention in the case of Israel’s former Prime Minister, Ariel Sharon. Mechanical removal of occlusions with the Merci retriever system was approved for use in patients with stroke in 2004. In one study (Devlin, Baxter, Feintuch, & Desbiens, 2007), single-center data focused on 25 consecutive patients where most instances of acute ischemic stroke followed isolated middle cerebral artery lesions. Successful reperfusion was obtained in about half of the Merci trials, although some patients with tandem proximal carotid and intracranial lesions were treated with carotid angioplasty and stenting, and not all patients were treated within the 3-hour window.

At present, decisions regarding areas for reperfusion, whether the intervention is medical, mechanical, or surgical, are based on an examination of the brain. The following sections of this report will address some of the limitations associated with visually based information.

Threats to Accurate Diagnosis

The advent of neural imaging techniques has presented a challenge to strict localizationists, who posit direct brain-behavior relationships. Evidence of reduced blood flow, narrowing, or obstruction in the left hemisphere MCA should correspond with impairments in function associated with the affected portion of the brain. That this is not always the case points to shortcomings both in localizationist theory and in neural imaging, as follows:

1. Hypoperfusion: Magnetic resonance perfusion weighted imaging can be useful in identifying hypoperfusion of specific brain regions, which may be associated with disruption of selective language functions. Pharmacological blood pressure elevation may increase regional brain perfusion and language function. Reperfusion of the ischemic and dysfunctional tissue can reveal brain/language relationships before the reorganization that follows a stroke (Hillis et al., 2001).

Localizing brain functions has been typically supported by evidence of shared areas of brain damage in individuals with a similar language deficit, and is sometimes called the “lesion overlap” approach. That is, if there is a functional deficit, then the area of the brain damaged in most of these individuals must have been responsible for that function. When the reciprocal association, the probability that the lesion caused the deficit, is evaluated, then the relationship may not be supported. Hypoperfusion does not necessarily specify area of infarct. For example, structural damage or low blood flow in the left posterior inferior frontal gyrus may result in poor drainage into the anterior insula. Reperfusion of the anterior insula will not relieve symptoms of apraxia of speech, a motor programming speech disorder associated with left frontal lobe damage (Hillis et al., 2004).

2. Polytypicality: Many adults with communication disorders, such as adults with poststroke aphasia, display language characteristics that cross diagnostic boundaries. The polytypic nature of aphasia highlights the limitations of classifications that require separate groupings and imply independence of individual language functions (Schwartz, 1984).

Virtually all aphasias involve reduction of available vocabulary, linguistic rules, and verbal retention span, as well as impaired comprehension and production of messages. It is not unusual for a patient with Broca’s aphasia, for example, to have difficulty in auditory comprehension, an impairment listed among the principal diagnostic characteristics of Wernicke’s aphasia. Curiously, the patient Broca described in 1861 (see Code[ 2013]), called “Tan” because that was his stereotypic utterance, did not have Broca’s aphasia. The combination of severe oral expressive deficit along with severe auditory comprehension deficit would probably be indicative of a global aphasia (Damasio, 2008).

Although type of language deficit is usually a reliable predictor of site of lesion, the reverse correspondence does not hold as closely. The “exceptions,” where lesions as corroborated by computerized tomography did not predict type of aphasia, ran about 16% or about one in six (Basso et al., 1985).

3. Brains versus veins: The underlying principle of functional magnetic resonance imaging (fMRI) is that magnetic properties of oxygenated blood are different from deoxygenated blood. The scan detects alterations in brain function or physiology associated with cognitive, motor, and sensory task performance. The gold standard of blood oxygenation level dependent (BOLD) technique is better than repeated injections of gadolinium (Gd) at generating images sensitive to the oxygenation level of blood. Arterial spin tagging is an approach similar to Gd, but arterial blood water is "tagged" magnetically using an RF pulse rather than by Gd injection.

Clinical applications have been limited to attempts to guide neurosurgery or radiation therapy to spare important functional tissue. Applications in neuroscience research include brain mapping studies using BOLD fMRI to assess language lateralization, word generation, and sentence comprehension. BOLD fMRI use in disease states has focused on recovery of language ability after stroke and mapping regional changes in activity during epileptic seizures. Publication of more than 40,000 articles reveal functional brain imaging to localize behavioral and cognitive processes to specific areas in the human brain is often not confirmed by traditional, lesion-based studies (Ross, 2010).

The “brains vs. veins” issue is related to the part of the functional signal that arises not from the brain capillaries and parenchyma (presumably at the site of activation), but rather from larger draining veins; accordingly, accuracy of localizing neural activity is limited.

4. Dumping it in the chocolate: There are frequent instances in our professions where we metaphorically dump the diagnosis in the chocolate. Some gratuitous examples occur in the diagnosis of “quirky” children with unspecified communication disorders. Catchall terms begin at birth, where the diagnosis of FLK (for funny-looking kid) has only recently been discontinued. In the Middle Ages, the medical diagnosis for quirky children was humors of the liver; more recently, the children were diagnosed with brain fever, minimum brain damage, and minimal cerebral dysfunction. Currently, the chocolate into which many of these children’s problems are dumped is the reticulo-limbic complex of the brain. Better than humors of the liver, but not by much.

Increasing Accurate Diagnosis

An accurate diagnosis depends on using a test or assessment procedure that has adequate control of several factors. The following examples are taken from a recent study (Baylow, Goldfarb, Taviera, & Steinberg, 2009) comparing efficacy of the chin-down posture in reducing aspiration in acute stroke via bedside evaluation or videofluoroscopy.

1. True and False Positives and Negatives. In any comparison of a test result with an accepted standard, the number of true and false positives and negatives is calculated from a 2 X[9] 2 table (Rosenbek, McCullough, & Wertz, 2004). True positives in the study by Baylow et al. (2009) were operationally defined as the number of participants who were predicted to have aspirated when drinking 1 cc of thin liquid without use of the chin-down posture on the clinical/bedside examination and who subsequently aspirated on videofluoroscopy (recorded in cell ‘‘a’’). True negatives were the number of participants who were not predicted to have aspirated when drinking 1 cc of thin liquid without use of the chin-down posture on the clinical/ bedside examination and who subsequently did not aspirate on videofluoroscopy (recorded in cell ‘‘d’’). False positives (cell ‘‘b’’) were those participants who were predicted by the clinician to have aspirated during the clinical/bedside examination and who subsequently did not aspirate on videofluoroscopy. False negatives (cell ‘‘c’’) were those participants who were predicted by the clinician not to have aspirated during the clinical/bedside examination and who subsequently aspirated on videofluoroscopy.

2. Sensitivity and Specificity Data Analysis. Sensitivity and specificity calculations are used to determine the value of a test. Sensitivity refers to the proportion of participants who have the sign (e.g., aspiration on videofluoroscopy) and who were also predicted to have a positive sign (e.g., aspiration with and without the chin-down posture on the clinical/bedside examination). Sensitivity is calculated by the number of true positives divided by the sum of the true positives and false negatives [SENS = a/(a + c)]. Specificity refers to the proportion of participants who did not have the sign (e.g., no aspiration on videofluoroscopy) and who were also not predicted to have a positive sign (e.g., no aspiration with and without the chin-down posture on the clinical/bedside examination). Specificity is calculated by the number of true negatives divided by the sum of the false positives and true negatives [SPEC = d/(b + d)].

3. Positive and Negative Predictive Values Data Analysis. The positive predictive value can be defined as the proportion of the participants who were positively predicted by the clinician to be aspirating with and without use of the chin-down posture during the clinical/bedside evaluation and who also aspirated during the videofluoroscopy. The negative predictive value can be defined as the proportion 3. of the participants who were positively predicted by the clinician to be not aspirating with and without use of the chin-down posture during the clinical/bedside evaluation and who also did not aspirate during the videofluoroscopy.

If the diagnostic instrument or measure you select controls for the variables above, you will reduce the likelihood of dumping your findings in the chocolate.

About the Author

Robert Goldfarb, Ph.D., is Professor and Program Director at Adelphi University, and Emeritus Professor at Lehman College and CUNY Graduate Center. He is a Fellow of the American Speech-Language-Hearing Association. His most recent book,Translational Speech-Language Pathology and Audiology: Essays in Honor of Dr. Sadanand Singh, launches in April

References

Bakker, K., Raphael, L. J., Myers, F. M. (Eds.). (2010). Proceedings of the first world conference on cluttering. Katerino, Bulgaria. http://associations.missouristate.edu/ICA

Basso, A., Lecours, A., Moraschini, S., & Vanier, M. (1985). Anatomoclinical correlations of the aphasias as defined through computerized tomography: Exceptions. Brain and Language, 26, 201–229.

Baylow, H. E., Goldfarb, R., Taveira, C., & Steinberg, R. (2009). Accuracy of clinical judgment of the chin-down posture for dysphagia during the clinical/bedside assessment as corroborated by videofluoroscopy in adults with acute stroke. Dysphagia, 24, 423–433.

Code, C. (2013). Significant landmarks in the history of aphasia and its therapy. In I. Papathanasiou, P. Coppens, & C. Potagas (Eds.), Aphasia and related neurogenic communication disorders (pp. 3–22). Burlington, MA: Jones & Bartlett Learning.

Damasio, H. (2008). Neural basis of language disorders. In R. Chapey (Ed.), Language intervention strategies in aphasia and related neurogenic communication disorders (5th ed.) (pp. 20–41.) Baltimore, MD: Lippincott Williams & Wilkins.

Devlin, T. G., Baxter, B. W., Feintuch, T. A., & Desbiens, N. A. (2007). The merci retrieval system for acute stroke: The southeast regional stroke center experience. Neurocritical Care, 6, 11–21.

Hillis, A. E., Kane, A., Tuffiash, E., Ulatowski, J .A., Barker, P. B., Beauchamp, N. J., & Wityk, R. J. (2001). Reperfusion of specific brain regions by raising blood pressure restores selective language functions in subacute stroke. Brain and Language, 79, 495–510.

Hillis, A. E., Work, M., Barker, P. B., Jacobs, M. A., Breese, E. L., & Maurer, K. (2004). Re-examining the brain regions crucial for orchestrating speech articulation. Brain, 127, 1479–1487.

Rosenbek, J. C., McCullough, G. H., & Wertz, R. T. (2004). Is the information about a test important? Applying the methods of evidence-based medicine to the clinical examination of swallowing. Journal of Commununication Disorders, 37, 437–50.

Ross, E. D. (2010). Cerebral localization of functions and the neurology of language: Fact versus fiction or is it something else? Stroke, 41, 1229–1236.

Schwartz, M. (1984). What the classical aphasia categories can’t do for us, and why. Brain and Language, 21, 3–8.

If you are attending, make sure to visit Plural Publishing at the following conferences—receive an exclusive conference discount, meet our authors, and browse our new publications.

February 2012-May 2012

February 2012
Illinois Speech-Language-Hearing Association Annual Convention
Rosemont, IL
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March 2012
Audiology Now!
Boston, MA
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California Speech-Language-Hearing Association Annual State Convention
San Jose, CA
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Dysphagia Research Society, annual meeting,
Toronto, Canada
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April 2012
Council of Academic Programs in Communication Sciences and Disorders (CAPCSD)
2012 CAPCSD Conference and Global Summit
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COSM – Combined Otolaryngology Spring Meetings
San Diego, CA
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May 2012
Voice Foundation Annual Symposium
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Newsdesk

Competition time! This month, we are offering a copy of Disorders of the Auditory System by Frank E. Musiek, Jane A. Baran, Jennifer B. Shinn, and Raleigh O. Jones

To enter, all you have to do is email your name and address to pluralcommunity, placing “February 2012 Competition” in the subject line. The drawing will take place on or around February 23, 2012, and the winner will be announced in the March 2012 issue of Plural Community.

Congratulations again to Patricia LaPierre from Stewart Manor, NY, who was the winner of our monthly competition for January and wins a free copy of School Programs in Speech-Language Pathology: Organization and Service Delivery, Fifth Edition. A copy is on its way to her, with our good wishes.

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