gms | German Medical Science

Phoniatrics is the medical specialty involved in the management of communication and swallowing disorders; physical, developmental, functional and behavioural aspects of verbal communication and swallowing can be taken care of in phoniatrics with competence [Ref. 1]. The field of communication disorders is primarily involved in the knowledge of the normal functioning of some human abilities and specifically of the following: voice, speech, language, hearing, non verbal and verbal communication, fluency of the above mentioned functions, swallowing, academic learning, and interpersonal relationship. The nosological catalogue could be divided into the following chapters: voice disorders, organic speech disorders, fluency disorders, aphasias, dysarthrias, retardations and dementiae, swallowing disorders, verbal disorders in the deaf and related disabilities and problems, learning disorders, socio-cultural and emotional troubles [Ref. 2], [Ref. 3].

Prevalence and incidence data are essential for health planning, and phoniatrics is no exception [Ref. 4]. Large epidemiologic studies on communication disorders in the general population barely don't exist [Ref. 5], [Ref. 6]; prevalence and incidence scores therefore are available for some diseases only, such as cleft palate or child deafness.

Aim of the study is to review the prevalence of the following disorders: primary child language impairment, reading disability, mental retardation, cerebral palsy, autism spectrum, tongue thrust, stuttering, cleft lip/palate, child deafness, dysphagia, aphasia, dementia, chronic dysphonia.

The human abilities the phoniatrician is asked to manage in his/her everyday clinical practice were searched in the Body functions section of the International Classification of Functioning Disability and Health (ICF) [Ref. 7]. The following have been considered in the study: hearing, voice, speech, language, swallowing. The main areas of a phoniatrician clinical practice were then linked to one of these five human functions. The areas of clinical practice considered were: child deafness, voice disorders, organic speech disorders, motor speech disorders, functional speech disorders, fluency disorders, primary language impairment, aphasia, mental retardation, dementia, pervasive developmental disorders, learning disability, deviate swallowing, dysphagia.

A non systematic review of the indexed literature was performed through the Pubmed website. The keywords used were: incidence, prevalence, epidemiology, specific language impairment, developmental dyslexia, reading disability, mental retardation, cerebral palsy, autism, Asperger, pervasive developmental disorder, tongue thrust, deviate swallowing, stuttering, cleft lip/palate, dysphagia, swallowing impairment, child deafness, motor speech disorder, dysarthria, aphasia, dementia, mild cognitive impairment, chronic dysphonia. The articles which appeared to have the best epidemiological design were used to estimate the prevalence.

The prevalence data found in the literature are reported in Table 1 [Tab. 1]. When feasible the prevalence data for each area of clinical practice was reported; when no data were found, it was reported the prevalence of the most important disease/disorder for that area. For instance, no data were found on the prevalence of organic speech disorders: prevalence of cleft lip/palate was therefore condered.

While for voice disorders the estimated prevalence is < 100/100.000, there are three areas related to the speech function whose prevalence is > 100/100.000; the area of fluency disorders has a prevalence of about 1.000/100.000. As for the areas linked to the language function, three of them have a prevalence > 1.000/100.000, while the remaining > 100/100.000. In the three areas of clinical practice linked to the swallowing function, the prevalence reported is well >1.000/100.000.

Estimated prevalence of patients in the main areas of phoniatrics clinical practice have been reported; data were obtained from a non systematic review of the literature, and should be considered with care. However, it appears that the patients with a language impairment, either primary or secondary to an intellectual or social problem, are the largest group; on the contrary subjects with a voice disorders or with a severe hearing impairment leading to a communication limitation represent a minor group from an epidemiological point of view.