Establishing normative values for swallow strength and timing in hospitalized patients

Oropharyngeal dysphagia (OD) is defined as difficult and/or disordered
swallowing of food (semisolid or solid), liquid or both and is a risk factor
for developing malnutrition, dehydration and community acquired pneumonia1. In
hospitalized patients OD has been associated with prolonged length of hospital
stay and increased risk of pneumonia, reintubation or death, imposing a
significant burden on patient well-being and healthcare costs.
Despite growing awareness of OD, a lot remains unknown regarding its
prevalence, incidence, pathophysiology, diagnostic testing and treatment
options.
Few studies have reported the prevalence of OD in hospitalized patients with an
overall prevalence of OD ranging from 5% to even 75% in elderly patients
admitted with a community acquired pneumonia.
There is a significant variability in the instrumentation used to objectively
establish and measure dysphagia, ranging from bedside screening methods, like
the Eating Assessment Tool (EAT-10) and the Volume-Viscosity Swallow test
(V-VST) to the highly sensitive and specific but invasive videofluoroscopy
(VFS) and the Fiberoptic Endoscopic Evaluation of Swallowing (FEES). Recently
the non-invasive method of surface electromyography (sEMG) is used to
characterize swallowing function concerning muscle activity in people with OD.
During swallowing more than 25 muscle pairs are used. sEMG is a non-invasive
method to measure muscle activity patterns of muscles used during swallowing.
Thereby the occurrence of swallowing and its physiology can be described. These
signals may be used in individual patients to evaluate changes in swallowing
function. sEMG has shown to be a promising tool to improve swallowing function
in patients with OD. sEMG is an intuitive, interactive way that uses
biofeedback and assists people with OD to perform swallowing exercises more
elaborately. sEMG is a fairly new early-intervention method, used in hospital
settings by speech and language therapists (SLT).
The effects of swallow exercises with sEMG can improve swallow function and
therefore quality of life.
In order to optimally use a sEMG program in dysphagia rehabilitation in
hospitals it is essential to understand sEMG scores on an individual as well as
a group level. Therefore sEMG programs should provide normative values of
swallow characteristics (e.g swallow strength and timing).
Characteristics of sEMG values of people with and without OD should be known to
be able to compare swallow strength and swallow timing of both groups with each
other. Thereby clinicians can evaluate 1) how deviant the swallow pattern of
the person with OD is in comparison with peers and 2) at which point the
swallow is accurate enough and treatment can be stopped. In existing screening
tools (e.g EAT-10, V-VST) the risk of OD can be detected, but no objective
information of swallow strength and timing can be derived. The provision of
these objective swallow characteristics enables clinicians to set adequate
goals for treatment.

This study aims to provide normative values for sEMG swallow function.
Clinicians using sEMG for clinical and research purposes may use this data for
a more complete understanding and interpretation of their results. Individual
results and changes in swallow function of hospitalized patients with OD may
hereby be placed within the broader context of normative values which
contributes to the quality of dysphagia care in hospitals. Prior to this study
similar data was collected in Gelre hospital in Apeldoorn in 2017. We plan to
combine this data with our data in a database to establish a representative
sample of normative values of swallowing.

Objective
1) To establish normative values for swallow strength and timing in
hospitalized patients.

Prospective, observational, mono-center study.

The sEMG measurement with Rephagia takes between 10 and 15 minutes altogether,
depending on the capabilities of the patient. This non-invasive measurement
takes about 20 minutes with a maximum of 30 minutes for the patient to complete
the full protocol (EAT 10, V VST and sEMG).
At any time a break can be taken or the measurement can be stopped completely
if this is the desire of the patient. Even though this measurement is scheduled
on a convenient time for the patient and other hospital staff, this measurement
will be stopped in case of acute care or family visits. If the patients like to
continue at another time a new appointment will be scheduled. If the
measurement is stopped during a specific part, it will be picked up from that
part (e.g. Rephagia swallow strength). Already collected data will not be
repeated.
There are no expected risks to participation in this study. Very vulnerable or
at risk patient for OD are excluded beforehand. Any illness affecting swallow
ability like extreme cold or influenza, are also part of the exclusion criteria.
When swallowing water, choking can occur and the residue will be coughed up.
Choking on water is not pleasant, but in itself not dangerous and can happen
spontaneously with any swallow.19,20 Choking on other foods or liquid than
water is more harmful, therefore strict use of water is chosen for this
protocol and only a small bolus (max 20 ml) is offered to the patient.19,20
Researchers are trained in handling choking incidents of choking in water and
medical staff is nearby.
The placement of the sensor on the throat can feel a bit strange, but is safe
and so far in previous studies like in Gelre hospital there has been no record
of complains of the material.
In case of oversensitive skin or wounds in that area, patients will be excluded.
Since patients are expected to swallow frequently throughout the measurement,
fatigue can occur. In case of fatigue a break can be taken or the measurement
can be stopped completely. In the study in Gelre hospital fatigue was not
reported as a common side-effect of the study.

The Gelre study showed that patients overall thought the measurement was quite
pleasant and enjoyed the kangaroo game in particular. We have no reason to
expect that the Zuyderland population will report different experiences.