Dysfluencies in the speech of adults with intellectual disabilities and reported speech difficulties

Marjolein C. Coppens-Hofman*, Hayo R. Terband, Ben A. M. Maassen, Henny M. J. van Schrojenstein Lantman-De Valk, Yvonne Van Zaalen-op't Hof, Ad F. M. Snik

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    10 Citations (Scopus)


    Background: In individuals with an intellectual disability, speech dysfluencies are more common than in the general population. In clinical practice, these fluency disorders are generally diagnosed and treated as stuttering rather than cluttering.

    Purpose: To characterise the type of dysfluencies in adults with intellectual disabilities and reported speech difficulties with an emphasis on manifestations of stuttering and cluttering, which distinction is to help optimise treatment aimed at improving fluency and intelligibility.

    Method: The dysfluencies in the spontaneous speech of 28 adults (18-40 years; 16 men) with mild and moderate intellectual disabilities (IQs 40-70), who were characterised as poorly intelligible by their caregivers, were analysed using the speech norms for typically developing adults and children. The speakers were subsequently assigned to different diagnostic categories by relating their resulting dysfluency profiles to mean articulatory rate and articulatory rate variability.

    Results: Twenty-two (75%) of the participants showed clinically significant dysfluencies, of which 21% were classified as clutterihg, 29% as cluttering-stuttering and 25% as clear cluttering at normal articulatory rate. The characteristic pattern of stuttering did not occur.

    Conclusion: The dysfluencies in the speech of adults with intellectual disabilities and poor intelligibility show patterns that are specific for this population. Together, the results suggest that in this specific group of dysfluent speakers interventions should be aimed at cluttering rather than stuttering.

    Learning outcomes: The reader will be able to (1) describe patterns of dysfluencies in the speech of adults with intellectual disabilities that are specific for this group of people, (2) explain that a high rate of dysfluencies in speech is potentially a major determiner of poor intelligibility in adults with ID and (3) describe suggestions for intervention focusing on cluttering rather than stuttering in dysfluent speakers with ID. (C) 2013 Elsevier Inc. All rights reserved.

    Original languageEnglish
    Pages (from-to)484-494
    Number of pages11
    JournalJournal of Communication Disorders
    Issue number5-6
    Publication statusPublished - 2013


    • Dysfluencies
    • Intellectual disabilities
    • Speech production
    • Cluttering

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