Orthognathic Speech Pathology: Phonetic Contrasts of Patients With Dental Discrepancies Pre- and Post-Treatment Analyses

Orthognathic Speech Pathology: Phonetic Contrasts of Patients With Dentofacial Discrepancies With Pre- and Post-Treatment Analyses


Lead Sponsor: University of North Carolina, Chapel Hill

Collaborator: North Carolina State University

Source University of North Carolina, Chapel Hill
Brief Summary

The investigators are studying how speech is effected by jaw and tooth position in jaw surgery patients. Eighty percent of our jaw surgery patients have speech pathologies, compared to five percent of the general population, but speech pathologists do not understand why. The investigators hypothesize that open bites and underbites prevent most patients from being able to pronounce words normally and surgical correction will lead to improvement in speech. Patients will be audio recorded speaking and patients' tongue gestures ultrasound recorded before and after their jaw surgeries to observe what changes occur in their speech and tongue movements.

Detailed Description

Purpose: The investigators are studying how phoneme distortion is effected by jaw disproportions in dentofacial disharmony (DFD) patients and whether speech improves after orthognathic surgery and orthodontic treatment. Spectral moment and tongue gestural analysis are being used to mechanistically determine how jaw position effects speech. The investigators hypothesize that skeletal open and underbites contribute to phoneme distortion and tongue gestural changes that improve following surgical correction of jaw position. All DFD patients are already seeking treatment from orthodontics and oral surgery. The study will observe how their speech changes before and after treatment. There is no randomization or intervention involved. Aim 1: Qualify the prevalence of auditory and visual speech distortions in the DFD population. Aim 2: Quantitatively evaluate the first spectral moment (kHz) of four articulating consonant sounds (/t/, /k/, /s/, and /?/ pronounced "sh"). Quantify and analyze the changes in speech distortions for orthognathic patients pre and post-operation. Aim 3: Evaluate tongue posture during speech with patients from Aim 2 pre and post-operation. Participants: Participants: Patients of the UNC dentofacial disharmony (DFD) clinic who have undergone orthognathic surgery for correction of jaw disharmonies. Procedures (methods): Patients will be recorded pronouncing a series of words highlighting a range of phonetic contrasts including --/s-sh/ and t-k/. words each presented on a screen using PowerPoint, 3 times each with carrier phrases). Recordings include an acoustic feed, a profile video of the jaws plus lips, and ultrasound imaging of the tongue relative to the palate and jaws. Research staff will score audio recordings according to their spectral moments and ultrasound recordings according to tongue movement and associate findings with degree of dental discrepancy. Prospective recordings will be collected at three timepoints: 1-3 months prior to jaw surgery, 3-8 months and 9-15 months post-operation for 60 overbite, 60 openbite and 60 underbite DFD patients. These time points were selected to co-occur with patients' surgical check-ups to ensure reliable data collection while minimizing confounding factors such as severe facial swelling and splint placement which occur immediately after surgery.

Overall Status Recruiting
Start Date 2019-09-11
Completion Date 2024-12-01
Primary Completion Date 2024-12-01
Study Type Observational
Primary Outcome
Measure Time Frame
Change in Speech Distortion Phonemes over Time pre-operation through 9-15 months post-operation
Change in Quantitative Tongue Gestures over Time pre-operation through 9-15 months post-operation
Enrollment 180

Intervention Type: Other

Intervention Name: Orthognathic surgery and Orthodontics

Description: This study is observational. All subjects identified to participate will be undergoing orthognathic jaw surgery and orthodontic treatment.

Arm Group Label: Dentofacial Disharmony Patients


Sampling Method:

Non-Probability Sample


Inclusion Criteria: - Jaw surgery patient at UNC with a skeletal open bite, underbite or overjet greater than 5mm. - Age 15-40 years Exclusion Criteria: - Hearing loss - Learned English as a second language - Significant regional accent, as characterized by a speech pathologist - Developmental delay, performing several grade levels below age bracket - history of craniofacial disorder - genetic syndrome associated with known craniofacial presentation - history of craniofacial trauma - history of prior craniofacial surgery (excluding extractions and dental procedures) - Jaw surgery without fixed orthodontic appliances



Minimum Age:

15 Years

Maximum Age:

40 Years

Healthy Volunteers:


Overall Official
Last Name Role Affiliation
Laura A Jacox, PhD, DMD, MS Principal Investigator Professor
Overall Contact

Last Name: Laura A Jacox, PhD, DMD, MS

Phone: 847- 702-0988

Email: [email protected]

Facility: Status: Contact: Investigator: University of North Carolina Laura A Jacox, DMD, PhD, MS 847-702-0988 [email protected] Laura A Jacox, DMD, PhD, MS Principal Investigator
Location Countries

United States

Verification Date


Responsible Party

Type: Sponsor

Has Expanded Access No
Condition Browse
Arm Group

Label: Dentofacial Disharmony Patients

Description: Dentofacial disharmony patients who are seeking jaw surgery in UNC oral and maxillofacial surgery department and are seen in UNC orthodontic dentofacial disharmony clinic.

Acronym OSP
Patient Data No
Study Design Info

Observational Model: Cohort

Time Perspective: Prospective

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