PhD Research Fellow

Speech Production and Swallowing with Full Dental Prosthesis

(May 28th, 2015)

Context

A position as PhD Research fellow is available in the PCMD (« Perception, Contrôle, Multimodalité et

Dynamiques de la parole ») research team in that GIPSA-Lab. This PhD is part of a research project

involving researchers from two different labs, Gipsa-lab in Grenoble and the LMI in Lyon. It is funded

by the Région Rhône-Alpes for 3 years from next fall, in the context of the research program ARC2

focusing on Quality of Life in the Elderly.

Scientific goals

The general objective of the thesis is to thoroughly study in patients the mechanical interactions

between a full dental prosthesis and the tongue during speech production and swallowing, and to

understand how it influences the control of these basic orofacial motor tasks and its evolution over

time. The work will be organized around three main tasks:

(1) The characterization of the mechanical stress exerted by the tongue on the dental

prosthesis, with a special focus on its amplitude, its spatial distribution and its variation

across patients.

(2) The study of the variation of the mechanical stress during the first weeks following the

insertion of the dental prosthesis in the patient’s mouth, during which a motor adaptation

takes place.

(3) The longitudinal study over years of the evolution of the mechanical stress and of the

potential links between this evolution and the emergence of speech production deficits

and /or swallowing diseases.

The measure of the mechanical stress will use the original

device elaborated at Gipsa-lab (Jeannin et al., 2008) (see

opposite figure). This device consists in 12 strain-gauge

sensors inserted in an exact replicate of the dental prosthesis

and distributed over the whole surface of the prosthesis. The

strain-gauge sensors have been specifically developed for this

purpose and the whole electronic setup matches the safety

regulation for an insertion in a patient’s mouth. Its insertion

within the dental prosthesis enables that it is not detectable by

the patient. Thus, its presence does not provide by itself a

perturbation of the motor task. Only the wires getting out from

the mouth corner are likely to induce a perturbation..

With this experimental study, we’d like to establish how patients adapt to the presence of the

prosthesis in their mouth, and how it can lead to the emergence of new, potentially pathological, motor

control strategies of speech production and swallowing. We make the hypothesis that this adaptation

could involve at least two different stages along which problems can emerge: (1) the elaboration in the

brain of an internal representation (a so-called internal model) of the oro-facial motor system including

the prosthesis, which memorizes the new links between motor commands, oro-sensory feedback and

accuracy of the achievement of the motor task (Wolpert et al., 1998); (2) the evolution of the motor

strategies on the basis of this new internal model. In line with studies of speech production in cochlear

implanted patients carried out by Perkell et al (2000), it can be expected that the decrease of the

accuracy of the afferent information due the presence of the prosthesis could induce a difficulty in the

maintenance of the internal models and, consequently, a decrease in the accuracy of the motor task.

The ultimate goal of the study is (1) via the establishment of a map of the contacts and their intensity

between the tongue and the prosthesis, to provide useful information for the design of prostheses and

of their insertion in the patient’ mouth, and (2) via the behavioral study of patients, to contribute to the

design of adapted training and reeducation protocols.

References

Jeannin, C., Perrier, P., Payan, Y., Dittmar, A., & Grosgogeat, B. (2008). Tongue pressure recordings during speech using

complete denture. Materials Science and Engineering C; 28, 835-841.

Perkell, J. S., Guenther, F. H., Lane, H., … & Zandipour, M. (2000). A theory of speech motor control and supporting data from

speakers with normal hearing and with profound hearing loss. Journal of Phonetics, 28(3), 233–272.

Wolpert, D., Miall, R. C., and Kawato, M. (1998). Internal models in the cerebellum. Trends in Cognitive Sciences, 2(9), 338–

347.

Skills

Taste for experimental work.

Ability to deal with patients and elderly people.

Statistical analysis of behavioral data.

Interest for cognitive sciences in general and learning issues in particular.

Salary:

According to French standards (about 1400 € net/month)

How to apply?

In order to apply, interested candidates should send from now their application (CV, transcript of

results, motivation letter and at least one reference) to:

Christophe.Jeannin@univ-lyon1.fr

Brigitte.Grosgogeat@univ-lyon1.fr

Pascal.Perrier@gipsa-lab.grenoble-inp.fr

If more information is needed, do not hesitate to contact us.