The study evaluated masseter muscle activity during swallowing using electromyography. It found that: 1) Masseter activity was higher for solid foods compared to liquids or pastes. 2) The highest percentage of muscle contraction occurred for liquids rather than pastes. 3) The protocol developed proved functional for collecting electromyographic data during swallowing of different consistencies.

1. The results of this study suggest that the masseter muscle activity is higher in solid
consistencies. However, the higher percentage of the muscle contraction was
obtained when testing the swallowing of food with liquid consistency instead of the
pasty one.
Electromyographic evaluation of the masseter in
the swallowing of food with different consistency
Contact: joana.filipa.hope@gmail.com
Joana Esperança, André Araújo, Ricardo Santos, Andreia Sousa, Paula Faria, Nelson Pereira.
Bibliography: (1) Rahal A. Eletromiografia. In: Fernandes FDM, Mendes BCA, Navas ALPGP. Tratado de Fonoaudiologia. 2 ed. São Paulo: Roca; 2010. (2) Crary MA. Biofeedback
eletromiográfico de superfície como terapia adjunta da disfagia. In: Furkim AM, Santini CRQSS. Disfagias Orofaríngeas. Vol 1. São Paulo: Prófono; 2008. (3) Moraes K, Cunha RA, Lins OG,
Cunha DA, Silva, HJ. Eletromiografia de Superfície: Padronização da Técnica. Revista de Neurobiologia. 2010; 73(3): 151-158. (4) Gabriel DA, Lester SM, Lenhardt SA, Cambridge ED.
Analysis of surface EMG spike shape across different levels of isometric force. Journal Neuroscience Methods. 2007; 159:146-152. (5) Hermes HJ, Freriks B. Development of
recommendations for SEMG sensors and sensor placemente procedures. Journal Electromyography Kinesiology. 2000; 10(5): 361-74. (6) Winter DA. Biomechanics and motor control of
human movement. 2 ed. Toronto: Wiley Interscience. 1990.
The Orofacial Motricity is one of the areas of clinical interest and research in Speech
Therapy. Surface Electromyography has been used as a complementary method of
diagnosis to develop normative data and characterization of different oral motor
disorders, including swallowing dysfunctions.
One of the applications of this method aims to monitor the electrical activity of the
muscles involved in swallowing. However there is a need to standardize the
procedures for collection and analysis of the electromyographic study of swallowing.
This study intends, this way, to contribute to the construction and validation
protocol for collecting electromyographic data during the swallowing of liquid, solid
and pasty, contributing to an increase in the knowledge of researchers carrying out
research work in this particular area.
Introduction
DESIGN OF THE STUDY:
Phase 1 – Preparatory study: creation/adaptation of the evaluation protocol.
- Literature review (construction of the protocol)
- Experts Panel – Professionals in the area of Surface Electromyography
and swallowing (adaptation of the protocol).
Phase 2 – Pilot Test: Full implementation and evaluation of the protocol.
-Quantitative, descriptive and transversal study of normal swallowing.
SAMPLE: 8 female young-adults aged between 18 to 25 years and presenting Angle
Class type I.
MATERIALS:
Data collection: Computer, Monitor Plux, EmgPlux System, Electrodes
DORMO, Impedance Meter, bioPLUX electromyograph research
Data processing: Acknowledge 3.9.0. and Microsoft Excel
Methods and Instruments
FEATURES AND RECOMENDATIONS OF THE EVALUATION PROTOCOL
Considering that the construction of the Surface Electromyography protocol is the
main objective of this study, a description of the characteristics and proceedings of
the protocol were also considered as results.
PHYSICAL CONDITIONS:
Quiet place, with low noise and/or distractions levels for the assessed subject and
for the evaluator.
PREPARATION OF THE SUBJECT:
The preparation of the evaluated subject comprises several steps, including:
DATA COLLECTION PROCEDURES:
Muscle selected for Surface Electromyography: masseter (bilateral).
Evaluation of reference:
Evaluation function (swallowing):
- Rest
- Maximal isometric contraction
- 10 ml of water (liquid)
- 10 ml of yogurt (pasty)
- 1 mini toast (solid)
Supplementary evaluation:
- Suprahyoid muscles (determine from the beginning to the end of the
swallowing).
DATA PROCESSING:
- Conversion of the Surface Electromyography signal from the Software
bioPlux, where it was collected, to the Acknowledge 3.9.0, where it was analysed.
- Determination of the swallowing moment: a closed time interval was assigned
to be common to all the muscles evaluated.
Surface Electromyography Protocol
 The procedural protocol of the Surface Electromyography proved to be functional
in collecting electromyographic data during the swallowing of liquids, pastes and
solids.
 The difference of values obtained in this study for the liquid and pasty
consistencies to the values presented on specialized literature can be explained
with factors such as the tested quantity and the swallowing process itself.
 It is suggested the use of this protocol in future investigations with larger
samples. The parameters must be replicated and a wider variety of quantities
should be tested.
Final Considerations
Results
Escola Superior de Tecnologia da Saúde do Porto
Subject’s Body
Positioning
Sitting with back and cervical support, with feet flat on the floor,
with the knees at 90º and with the gaze directed forward.
Skin Preparation
The skin should be exfoliated, shaved and cleaned with alcohol
to allow a better signal capture and decrease its impedance.
Determining the
position of the
electrodes
Masseters: It was carried out a track that determines the
insertion between the line that goes from the commissure to the
tragus of the ear and the line that goes from the outer corner of
the eye to the angle of the jaw.
Suprahyoid muscles: Electrodes are placed below the chin
from the genian spine.
Earth electrode: It’s placed on the lateral epicondyle of the
right elbow.
Electrodes’
placement
Both active electrodes should be placed along the muscle fibres.
0
500
1000
1500
2000
2500
Right
Masseter
Left
Masseter
Percentageofmuscular
activity
Muscle
Maximum muscular activity
vs basal activity
Liquid
Pasty
Solid
0
10
20
30
40
50
60
Right
Masseter
Left
Masseter
Percentageofmuscular
activity
Muscle
Maximum muscular activity vs
Maximal Voluntary Contraction
Liquid
Pasty
Solid