The World Health Organization’s International Classification of Functioning, Disability and Health (ICF) framework1 provides multiple perspectives – body structure and function, activity, and participation as well as contextual factors (personal and environmental) – to guide communication intervention.2 Adequate speech, language, and hearing require sufficient body structure (i.e. anatomy) and function (i.e. physiology). Speech, language, and hearing skills are used to communicate (i.e. to send and receive messages) with familiar and unfamiliar partners. Communication is crucial in order to participate in many home, school, work, and other community activities. In addition, personal factors (e.g. age and sex) and environmental factors (e.g. communication partners’ characteristics) may affect successful communication. One can use this biopsychosocial framework to evaluate intervention research.

Pennington et al. describe intelligibility outcomes of a speech systems intervention for 16 adolescents with moderate to severe dysarthria secondary to cerebral palsy (CP).3 After receiving three individual sessions per week for 6 weeks, the mean word intelligibility improved by 10% or more. However, as Table II in the Pennington et al. article shows, intelligibility for any one individual improved from zero to greater than 50%. The authors noted the need for more research to explain individual responses to interventions, to assess the effects of intervention younger children, and to consider other outcomes including increased participation in home, school, and community.

The ICF framework can be used to increase understanding of the Pennington et al. research and to suggest future research directions. A speech systems approach intervenes at a body function level by considering how each speech system – respiratory, phonatory (i.e. laryngeal), velopharyngeal (i.e. oral/nasal cavity division), and supralaryngeal articulation (i.e. oral cavity) – may be contributing to or interfering with speech production. Intervention techniques including those used by Pennington et al. target one or more of these individual speech systems.4–6 However, systematic literature reviews4,5 indicate that these interventions need additional evidence, especially when applied to CP. Pennington et al.’s research is a step towards filling this need.

Intervention outcomes can be measured at a body function level through perceptual judgments (e.g. loudness), physiological changes (e.g. ribcage movement), acoustic speech measurements (e.g. fundamental frequency changes), and speech intelligibility; at an activity level through conversational intelligibility and communication effectiveness; and at a participation level through increased societal roles within and/or across life situations.4–6 In their pilot study, Pennington et al. did not report any perceptual, physiological, acoustic, or participation outcomes, but did acknowledge the need for participation outcomes to be measured in future research.

Although the authors explained their rationale for choosing intelligibility measures, outcomes from multiple ICF perspectives would increase understanding of the effects of interventions on body structure/function, activity, participation, and environment. Increased participation is the ultimate goal of intervention, but the relationship of body structure/function and activity to participation outcomes may be especially important for individuals not showing increased intelligibility after receiving intervention. Did some individuals in the Pennington et al. study show improvement in speech system function which did not translate into increased intelligibility?

Physiological measures can improve without a corresponding increase in listener understanding.5 Listener factors include the task (e.g. identifying a word from a multiple choice list, understanding the general idea of the message, transcribing each word or sound), familiarity with the speaker and the message, language ability, the message length, background noises, and visual/contextual cues.6,7 The intelligibility of a speaker can vary owing to speech system function and the speaker’s task (e.g. repeating a word, telling a story, debating a controversial proposal).6,7 We have much to learn about how speech system components, both separately and in combination, create understandable communication and how listeners extract meaning from messages received in challenging situations.8 Outcomes across the ICF levels should be selected to further our understanding of these complex interactions.

Pennington et al. noted that some individuals compensated for unintelligible speech by using augmentative and/or alternative communication (AAC) to participate in daily activities.6 AAC includes speech generating devices (SGD), pictures, words, alphabet boards, manual signs, and gestures. Some individuals with dysarthria use multiple methods of communication. For example, one may use speech with familiar listeners and AAC with unfamiliar listeners or in formal speaking situations such as school or work. Individuals will usually need communication intervention to combine these strategies effectively.6 These compensatory approaches intervene at activity, participation, and environmental levels. Body function, activity, and/or participation outcomes could be analysed by type of communication method (e.g. speech, gesture, speech generating device).

Communication intervention research, designed with careful consideration of the ICF, is needed. The ICF framework should be used to foster discussions about what outcomes are meaningful to individuals with CP.


  1. Top of page
  2. References
  • 1
    World Health Organization. International Classification of Functioning, Disability and Health: ICF. Geneva: World Health Organization, 2001.
  • 2
    Threats TT. Towards an international framework for communication disorders: use of the ICF. J Commun Disord 2006; 39: 25165.
  • 3
    Pennington L, Miller N, Robson S, Steen N. Intensive speech and language therapy for older children with cerebral palsy: a systems approach. Dev Med Child Neurol 2009; in press.
  • 4
    Yorkston KM, Hakel M, Beukelman DR, Fager S. ANCDS bulletin board. Evidence for effectiveness of treatment of loudness, rate, or prosody in dysarthria: a systematic review. J Med Speech Lang Pathol 2007; 15: xixxxvi.
  • 5
    Yorkston KM, Spencer KA, Duffy JR. ANCDS bulletin board. Behavioral management of respiratory/phonatory dysfunction from dysarthria: a systematic review of the evidence. J Med Speech Lang Pathol 2003; 11: xiiixxxviii.
  • 6
    Hustad KC, Weismer G. Interventions to improve intelligibility and communicative success for speakers with dysarthria. In: WeismerG, editor. Motor Speech Disorders: Essays for Ray Kent. San Diego: Plural Pub, 2007; 261303.
  • 7
    Kent RD, Miolo G, Bloedel S. The intelligibility of children’s speech: a review of evaluation procedures. Am J Speech Lang Pathol 1994; 3: 8195.
  • 8
    Kent RD. Hearing and believing: some limits to the auditory-perceptual assessment of speech and voice disorders. Am J Speech Lang Pathol 1996; 5: 723.