Aerodynamic and acoustic characteristics of a speaker with turbulent nasal emission: a case report

The Nature of Nasal Fricatives: Articulatory-Perceptual Characteristics and Etiologic Considerations

Nasal fricatives (NFs) are unusual, maladaptive articulations used by children both with and without palatal anomalies to replace oral fricatives. Nasal fricatives vary in articulatory, aerodynamic, and acoustic-perceptual characteristics with two generally distinct types recognized. One type is produced with velopharyngeal (VP) constriction that results in turbulent nasal airflow and, frequently, tissue vibration (flutter) at the VP port. Trost (1981) described these as posterior NFs that have a distinctive snorting quality. A second type of NF is produced without significant VP constriction resulting in turbulent airflow generated at the anterior liminal valve of the nose. Of importance, both types are "active" alternative articulations in that the speaker occludes the oral cavity to direct all airflow through the nose (Harding & Grunwell, 1998). It is this oral gesture that differentiates NFs from obligatory (or passive) nasal air escape that may sound similar due to incomplete VP closure. The purpose of this article is to (1) describe the articulatory, aerodynamic, and acoustic-perceptual nature of NFs, and (2) propose a theoretical framework for the acquisition of NFs by children both with and without cleft palate.

Application of the International Classification of Functioning, Disability, and Health–Children and Youth Version (ICF-CY) to Cleft Lip and Palate

Objective

In recent health policy discussions, the World Health Organization has urged member states to implement the International Classification of Functioning, Disability, and Health: Children and Youth Version in their clinical practice and research. The purpose of this study was to identify codes from the International Classification of Functioning, Disability, and Health: Children and Youth Version relevant for use among children with cleft lip and/or palate, thereby highlighting the potential value of these codes for interprofessional cleft palate-craniofacial teams.

Design

The scope of recent published research in the area of cleft lip and/or palate was reviewed and compared with meaningful terms identified from the International Classification of Functioning, Disability, and Health: Children and Youth Version. In a five-step procedure, a consensus-based list of terms was developed that was linked separately to International Classification of Functioning, Disability, and Health: Children and Youth Version categories and codes. This provided a first draft of a core set for use in the cleft lip and/or palate field.

Conclusions

Adopting International Classification of Functioning, Disability, and Health: Children and Youth Version domains in cleft lip and/or palate may aid experts in identifying appropriate starting points for assessment, counseling, and therapy. When used as a clinical tool, it encourages health care professionals to go beyond treatment and outcome perspectives that are focused solely on the child and to include the children's environment and their familial/societal context. In order to establish improved, evidence-based interdisciplinary treatments for children with cleft lip and/or palate, more studies are needed that seek to identify all the influencing conditions of activities, children's participation, and barriers/facilitators in their environments.

Perceptions of Audible Nasal Emission in Speakers with Cleft Palate: A Comparative Study of Listener Judgments

Objective

Audible nasal emission is a common speech distortion observed in persons with cleft palate. This study examined the validity and reliability of perceptual judgments of audible nasal emission using interval scaling and magnitude estimation techniques.

Participants

Speech samples were collected from six adolescents with repaired cleft palate, all of whom demonstrated audible nasal emission. A total of 31 adults performed rating tasks in which they judged the severity of audible nasal emission in speech samples.

Measures

Occurrences of audible nasal emission in speech samples were identified using visual and auditory inspection. Using an acoustic modification technique, samples were digitally modified to amplify perceived occurrences of audible nasal emission to create three stimulus conditions. The original recording of the speech samples served as a control condition. The severity of audible nasal emission in the samples was judged by multiple listeners using interval scaling and magnitude estimation without a modulus. Statistical analysis included analysis of variance, regression, and curve-fitting methods.

Results

Magnitude-estimation ratings demonstrated stronger evidence of validity and reliability than interval scaling. A curvilinear relationship was found between the sets of ratings.

Conclusions

The results of this study suggest that audible nasal emission may be a prothetic or ratio-level perceptual continua. Listeners should consider using magnitude estimation or other ratio-based methods for perceptual judgments of audible nasal emission.