Research Report Abstracts - Gesundheit

eS240
Research Report Poster Display
Number: RR-PO-201-15-Thu Thursday 23 June 12:00
RAI: Exhibit Halls 2&3
SURFACE ELECTROMYOGRAPHY PATTERN OF
MASSETER, ORBICULARIS ORIS AND
SUBMENTAL MUSCLES DURING SWALLOWING
OF DIFFERENT CONSISTENCIES IN HEALTHY
SUBJECTS
Corti G. 1 , Ghiggi A. 2 , Murelli M. 2 , Tettamanti A. 1,2 , Gatti
R. 1,2
1San Raffaele Hospital, Rehabilitation Department, Milan,
Italy, 2Vita-Salute University, School of Physiotherapy,
Milan, Italy
Purpose: This work aimed at clarifying the pattern of sEMG
activation of masseter, orbicularis oris and submental muscles
during swallowing of different bolus consistencies. Moreover
the study explored the possibility of applying to these muscles
the normalisation procedure of sEMG intensity data through
maximal isometric contraction.
Relevance: Surface electromyography (sEMG) is a useful
methodology for evaluation and treatment of dysphagia.
However studies on this topic have not yet reached clear
and standardized patterns regarding duration and intensity
of EMG activation, and record of intensity data are
mainly based on absolute mvolts values, with possible
biases related to electrodes positioning, cross talk and skin
impedance.
Participants: Twenty-five healthy subjects were recruited
among students of the degree course in physiotherapy of San
Raffaele University of Milan. Age ranged between 18 and 25
years, while gender distribution was of ten males and fifteen
females.
Methods: Pairs of standard bipolar electrodes were positioned
for each muscle, making reference to previous sEMG
studies and to anatomical correlation studies. sEMG record
made use of an 8 channel Telemg BTS (Milan) with preamplification
and wireless transmission from the subject to
the receiver station; acquisition frequency was set at 1000 Hz,
while low and high pass filter from 50 to 250 Hz. Subjects
performed first three maximal isometric contractions for each
muscle and then three swallowing trials for each of the following
consistencies: saliva, water, semi-liquid and solid bolus.
Duration was recorded by visual assessment of sEMG curve,
while intensity data were normalised computing the activation
of the respective muscles during maximal isometric
contractions with gestures different from swallowing.
Analysis: Statistical analysis made use of SPSS 13.0 program,
and considered milliseconds raw values for duration
and the percentage of maximal activation values for intensity.
The following tests were used: the Kolmogoro–Smirnow
test for checking the normality of raw values, the analysis of
variance for comparing the three trials of each swallowing
task, the analysis of variance with contrasts for studying the
interaction between muscles and food consistency. P value
was set at 0.05 and for multiple comparisons a Bonferroni
correction to 0.01 was included.
Results: Concordantly with previous studies the results
reported, both for duration and intensity, a great inter subject
and intra subject variability. Despite this, the study could
retrieve some important pattern variations related to bolus
consistencies: (a) duration of the total swallowing event as
well as orbicularis oris and submental muscles’, increase with
bolus viscosity, whereas masseter’s duration does not vary
significantly; (b) sEMG intensity of masseter and submental
muscles increases together with viscosity whereas orbicularis
oris’ together with volume.
Conclusions: These data confirm, even from a sEMG point
of view, the different role of the three muscles during single
swallowing: anterior containment for orbicularis oris,
mandible fixation for the masseter, hyoid elevation for submental
muscles.
Implications: sEMG could be a valid support for evaluating
functional deficit of swallowing and plan proper intervention
aimed both at muscle training and diet selection. sEMG
intensity as percentage of maximal activation could be a valid
procedure for overcoming biases due to electrodes positioning.
Keywords: Surface electromyography; Deglutition; Muscle
pattern
Funding acknowledgements: None.
Ethics approval: The study was approved by the internal
ethical committee of San Raffaele hospital.