About the presenter: Carla Di Domenicantonio is a registered speech-language pathologist in Ontario, Canada. She has worked in the field of stuttering and fluency disorders for over 25 years serving preschool, school-aged and adult populations in hospital and private clinic settings. Eager to support the advancement of cluttering amongst colleagues and the general population, Carla became the Canadian SLP representative for the International Cluttering Association (ICA) in 2007.


Cluttering: Should We Be Looking at Central Auditory Processing Abilities?

by Carla Di Domenicantonio
from Canada


Descriptions of cluttering reveal it to be a complex, multifaceted disorder presenting disturbances in speech production relating to various aspects of articulation, fluency and language. Additional behavioral, attentional, perceptual, physical and motor characteristics have also been attributed to persons who clutter (Daly, 1996).

In addition, cluttering has been associated with various other disorders such as attention deficit disorder (Daly, 2007), Asperger syndrome (Scaler-Scott, 2008), Down syndrome (VanBorsel & Vandermeulen, 2008), and Tourette syndrome (VanBorsel & Vanryckeghem, 2000; VanBorsel et al., 2004).

Most often cluttering has been associated with stuttering. The two speech disorders are reported to co-occur in most instances of cluttering diagnosis (Daly, 2007). The two are also linked because of the disfluent speaking behaviors that are evident in both disorders.

In a 1980 article, Tiger and her colleagues proposed that cluttering has more in common with learning disabilities than it does with stuttering. Cluttering symptoms that are consistent with those found in learning disabilities are discussed and illustrated through a case presentation. The shared characteristics are: "language disorders in all modalities, speech disturbances, and perceptual/motor deficits." Lack of awareness is listed as a fourth shared feature. The authors state that because of its close association to stuttering, speech-language pathologists were focusing on treating the speech symptoms of cluttering, while overlooking underlying perceptual (auditory and visual) and linguistic deficits.

Auditory Processing and Cluttering

Since the article by Tiger and her colleagues was published there have been few studies that have investigated the auditory perceptual dimensions of cluttering in a systematic fashion. A search of the literature produced three published studies that have focused on auditory processing skills specifically in clutterers.

The first study of auditory processing, completed by Wolk (1986), involved a single subject: a 26 year old adult male clutterer. The study's aim was to conduct "an in-depth diagnostic evaluation" which included the administration of a dichotic CV (consonant-vowel) listening task to investigate central auditory perception. In dichotic tasks, two competing acoustic stimuli are presented simultaneously to each ear. In this case, the subject would have heard one CV combination, for example /pa/, in the right ear, and a different CV combination in the left ear - for example /da/. Only plosive consonants were used (p, t, k, b, d, g) in combination with the vowel /a/. The article does not explain whether the subject was instructed to repeat both CV combinations; one CV combination from a specified ear; or both CV combinations in a specified order (i.e., CV combination delivered to right ear first, followed by CV combination heard in left ear).

The study looked at "overall performance, laterality effect and analyzed phonemic features of the CV combinations" relative to performance. The subject was reported to demonstrate a "generally lower performance when compared to normals." A right ear advantage was revealed "with a slightly larger ear difference than has been reported for normals." Some consonant sounds were identified correctly more often than others. Errors were associated to place perception (i.e., where in the mouth the sounds were made) more often than they were linked to perception of voicing.

Wolk summarized the findings for this subject as suggesting "a disturbance in central auditory processing, possibly a specific disturbance in place perception." She encouraged further investigation of auditory processing abilities in adults with cluttered speech.

A second study by Molt (1996) was the first to use a control group. Molt's study examined central auditory processing in three school-aged male clutterers who were also diagnosed with attention deficit disorder, with hyperactivity in one subject and without hyperactivity in the other two. Two of the boys also had a diagnosed learning disability. This study compared the subjects' performance to three normal speaking control subjects that were matched in age and gender. The study used two linguistically based measures and two nonlinguistic tests to examine auditory processing ability, and used auditory event-related potential topographic mapping in all six subjects.

Linguistically based measures of auditory processing consisted of the Staggered Spondaic Word Test (monotic/dichotic) and the Low Pass Filtered Test (monotic). In monotic or monaural tasks the auditory stimulus of interest is presented to one ear only, removing the element of competition. Non-linguistic tasks included the Frequency (Pitch) Pattern Sequence Test, the Seashore Rhythm Test, and a subtest of the Seashore Measures of Musical Talent. Molt explains the requirements for each of these tasks in detail. Combined, these tests were reported to examine various parameters of auditory processing ability.

Molt found that all three clutterers performed below normal on at least two of the four central auditory processing tasks administered. Two subjects failed three of the subtests. All three failed the Staggered Spondaic Word Test; error patterns, however, were unique to each subject. The clutterers also demonstrated abnormal auditory evoked potential waveform features, which Molt characterized as lending further support for an underlying processing disorder. In contrast, all three control subjects scored within normal expectations on all four central auditory processing tasks and demonstrated appropriate auditory evoked potential waveform patterns.

The most recent study was conducted by Blood and his colleagues (2006) who looked at auditory processing in six young children diagnosed as clutterers who had average performance at school, thus eliminating learning disabilities from the study. A carefully matched control group was included in the study. Four tests were administered: the Dichotic Listening Test which, based on the description provided, used similar CV acoustic stimuli as in the Wolk study; the Staggered Spondaic Word Test as was used by Molt; a test of time compressed speech; and, the Auditory Continuous Performance Test to assess auditory attention abilities.

Similar to Wolk and Molt, Blood and his colleagues found evidence of central auditory processing differences in subjects with cluttered speech. It would be inappropriate to compare the Dichotic Listening Test results obtained by Wolk to those of Blood and his colleagues because of the age difference in the subjects. It is also unclear whether the tasks were exactly the same. Similar to Molt, however, below normal performance was revealed for five of the cluttering subjects on the Staggered Spondaic Word Test. The researchers state this finding "indicative of some type of auditory processing problem." Control subjects all scored within normal expectations. No difference was found in overall group performance for time compressed speech or on the Auditory Continuous Performance Test; however, there was variability within the cluttering group with two of the children scoring somewhat lower than the others.

Blood and his colleagues view their results as providing some support for the possible implication of auditory processing and subtle attentional deficits in cluttering, and propose that future studies examine both individual and group data, compare cluttering and stuttering subjects, and assess both auditory and visual attentional processing systems.

All three studies therefore found differences in auditory processing in their small group of cluttering subjects. While it would be premature to generalize these results to all clutterers, they nonetheless point to a possible relationship between central auditory processing and cluttering. This relationship may exist for some and not necessarily all clutterers. Hopefully, our researchers will probe into this area further, and also address linguistic factors in cluttering.

Clinical Relevance

While the testing of auditory processing may not be essential for all fluency clients, it may be relevant for some, especially when there are speech and language disturbances accompanying disfluent speech. Auditory processing testing becomes even more relevant when there is learning, listening or "attentional" difficulty reported. If we have reason to suspect an auditory processing or linguistic component for a particular client, it is our responsibility to provide the necessary testing, whether we administer it ourselves or refer clients to a more appropriate colleague or professional.

There are standardized tools available to speech-language pathologists which can help identify potential auditory processing deficiencies. The Differential Screening Test for Processing (DSTP) by Richard and Ferre (2006) is one example that is suitable for children between the ages of 6 and 12. This test looks at three levels of auditory processing which are described as separate but interactive relative to each other, depending on the task. The first level of processing is central auditory processing. The auditory signal travels from the ear to the brain and is differentiated according to its acoustic features. The second level of processing involves the analysis (by the brain) of linguistic-phonemic aspects of the auditory signal. Meaning (comprehension) is assigned to the auditory signal at the third level of processing. The DSTP is designed to identify deficit areas in any of the three levels, signaling the need for further assessment or referral to another professional. This seems a reasonable, time efficient way to begin exploring the auditory processing continuum in fluency clients.

Should the need for further testing be revealed, the speech-language pathologist has at her disposal an assortment of standardized test instruments which can add valuable information to the client's auditory-linguistic processing profile.

For potential deficits at the first processing level, the SCAN-3 Tests for Auditory Processing Disorders (Keith, 2009) can be administered by speech-language pathologists, as stated by the author. The SCAN-3 allows the speech-language pathologist to measure auditory processing skills, to report standard scores and percentile ranks that yield descriptive classifications (Normal, Borderline, Disordered) for individual subtests and for overall test performance. (It would not be appropriate for a speech-language pathologist to "diagnose" a central auditory processing disorder. Diagnosis should be left to the audiologist.)

It is advisable that any speech-language pathologist who is new to administering the SCAN-3 obtain mentoring and supervision from a qualified audiologist who is knowledgeable and experienced in central auditory testing. (A dually certified professional would be the ideal.) It is important to be able to interpret test results appropriately. Examining subtest results relative to each other and analyzing client responses to individual items can provide valuable information towards recommendations and intervention plans.

Further analysis of second and third level processing skills can be achieved with standardized language tests. Tests or subtests that tap into phonological and phonemic skills may provide additional information about second level processing, while tests or subtests focusing on semantic and morphological aspects of language will allow more in-depth evaluation of third level processing abilities. Additional skills such as memory, executive function and self-regulation may need to be examined as well.

Closing Remarks

Systematic studies investigating neurologically based skills, such as auditory processing and language processing, are lacking for the area of cluttering. One of the research challenges is the absence of a universally accepted definition of cluttering and the seeming myriad of other problems which occur alongside cluttering, or within which cluttering occurs, creating multiple subgroups of clutterers. Three published studies have examined the potential implication of central auditory processing deficiencies in clutterers across different groups and ages. All three found deficiencies in how clutterers performed relative to "normal" peers (two studies used control groups; one used test norms) and asserted that further investigation is warranted. It may be some time before this research is completed and available to practicing clinicians. In the meantime, speech-language pathologists can choose to complete their own individualized "investigations" of potential auditory-linguistic processing contributions to cluttering symptoms in order to better serve their clients' needs.


Daly, D. (1996) The Source for Stuttering and Cluttering. East Moline, IL: Linguisystems, Inc.

Daly (2007) Identifying and Treating Cluttering: Effective Strategies Clinicians Need to Know. ASHA Convention Boston, MA.

Blood, G.W., Blood, I.M., and Tellis, G. (2000). Auditory processing and cluttering in young children. Perceptual and Motor Skills, 90, 631-639.

Geffner, D. & Ross-Swain, D. (2007) Auditory Processing Disorders: Assessment, Management, and Treatment. San Diego, CA: Plural Publishing, Inc.

Keith, R.W. (2009) SCAN-3 Tests for Auditory Processing Disorders. San Antonio, TX: Pearson Education, Inc.

Molt, L. F. (1996). An examination of various aspects of auditory processing in clutterers. Journal of Fluency Disorders, 21, 215-225.

Richard, G.J. & Ferre J.M. (2006) Differential Screening Test for Processing. East Moline, IL: Linguisystems, Inc.

Scaler-Scott, K. & Ward, D. (2008) Treatment of Cluttered Speech in Asperger's Disorder: Focus on Self-Regulation. ASHA Convention, Chicago, IL.

Tiger, R.J., Irvine, T.L., Reis, R.P. (1980) Cluttering as a comples of learning disabilities. Language, Speech, and Hearing Services in Schools, XI, 3-14.

VanBorsel, J., Goethais, L. & Vanryckeghem, M. (2004) Disfluency in Tourette Syndrome: Observational Study in Three Cases. Folia Phoniatrica et Logopaedica, 56:358-366.

VanBorsel, J. & Vandermeulen, A. (2008) Cluttering in Down Syndrome. Folia Phoniatrica et Logopaedica, 60:312-317.

VanBorsel, J. & Vanryckeghem, M. (2000) Dysfluency and Phonic Tics in Tourette Syndrome: A Case Report. Journal of Communication Disorders, 33, 227-240.

Wolk, L. (1986) Cluttering: a diagnostic case report. British Journal of Disorders of Communication, 21, 199-207.


SUBMITTED: April 6, 2010

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