REVIEW PAPER
SPEECH DIFFICULTIES AND POOR SPEECH INTELLIGIBILITY IN ADULTS WITH DOWN SYNDROME: A REVIEW OF THE LITERATURE
 
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1
Radboud University Nijmegen Medical Centre – Department of Medical Psychology and NCEBP
2
University of Groningen, Centre for Language and Cognition (CLCG)
3
Radboud University Nijmegen Medical Centre – Department of Primary and Community Care
4
Radboud University Nijmegen Medical Centre – Department of Otorhinolaryngology and Donders Institute for Brain, Cognition and Behaviour
CORRESPONDING AUTHOR
Marjolein C. Coppens-Hofman   

Marjolein C. Coppens-Hofman, Radboud University Nijmegen Medical Centre, Department of Medical Psychology, Postbus 9101, 6500 HB Nijmegen, The Nederlands, Tel.: +31 64 987 4481, e-mail: m.coppens@mps.umcn.nl
Publication date: 2020-04-20
 
J Hear Sci 2012;2(1):9–16
 
KEYWORDS
ABSTRACT
Background:
This review gives an overview of studies on speech difficulties in adults with Down syndrome to identify causes and major determinants of poor speech intelligibility for this group and to suggest areas requiring further research.

Material and Methods:
Exactly 39 published articles were selected by using the following MEsH search terms: speech disorders, articulatory apraxia, phonological impairment, articulation disorders, short-term memory, speech articulation disorders, and speech intelligibility. Articles were grouped for analysis based on themes related to underlying causes of speech difficulties and the diagnosis and treatment of speech difficulties. Future research needs are also presented.

Results:
Speech problems in adults with Down syndrome are not clearly defined. There is no specific data on underlying mechanisms that negatively impact on speech and there is no systematic assessment procedure available for evaluating the speech of adults with Down syndrome. Few studies have investigated treatment possibilities for speech disorders in adults and future research is needed into speech difficulties in adults with Down syndrome.

Conclusions:
Research is required into therapeutic programs to improve the speech of adults with Down syndrome. One clinical consideration as to why this research is lacking might be that the speech problem is seen as a characteristic of the Down syndrome itself rather than being seen as the result of distinct underlying deficits that may be sensitive to speech therapy. To aid therapeutic program development, longitudinalstudies of adolescents and adults with Down syndrome are required. Special attention could be given to investigating oral-motor characteristics and apraxia of speech.

 
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