Videofluoroscopic Swallowing Study (VFSS)

The study procedure of simultaneous VFSS and DDS measurement will be completed in one day and the subject will be followed within 2 business days after the study procedure to monitor for adverse events.

DDS signals and VFSS will be recorded simultaneously (for the same bolus) using barium contrast agent stimuli prepared in three consistencies: thin, mildly-thick and moderately-thick. Subjects will undergo VFSS with simultaneous DDS using up to 5 boluses of thin barium stimulus ("THIN-Ba"), and up to 4 boluses of barium thickened to mildly ("MILD-Ba") thick and up to 4 boluses of moderately ("MODERATE-Ba") thick barium consistencies using Resource Thicken Up Clear Nestlé Health Science (TUC). 4, 3 and 3 boluses for THIN-Ba, MILD-Ba and MOD-Ba will be analyzed using the classifier algorithms for sensitivity/specificity results. According to the exploratory trial, VFSS data for safety or efficiency can be missing for up to 14% boluses due to quality of VFSS recording. To compensate for potential losses of boluses due to missing gold standard (VFSS) data, 5, 4 and 4 boluses will be collected for the three consistencies respectively . The DDS signals will be sent to a dedicated application software installed at the CRO, which interprets the acceleration data and displays the examination result. The VFSS recording will be sent to CRO and provided for blinded assessment by the independent central VFSS laboratory.The study procedure of simultaneous VFSS and DDS measurement will be completed in one day and the subject will be followed within 2 business days after the study procedure to monitor for adverse events.

Eligibility Criteria:
Inclusion Criteria:

* Adult subjects (over 18 years of age)
* Hospitalized subjects or outpatients identified as at risk of oropharyngeal dysphagia (using local practice)
* Patients belong to one of the following groups:

  * Stroke patients
  * Traumatic brain injury
  * Parkinson Disease (PD) stage III or higher by Hoehn and Yahr scale
  * Multiple Sclerosis (MS) above age 60
  * Alzheimer Disease (AD) or other Dementia
* Other medically complex hospitalized subjects not covered by the exclusion criteria and identified as at risk of dysphagia
* Subject is able to comply with VFSS protocol to diagnose dysphagia
* Subject is able to give voluntary, written informed consent to participate in the clinical investigation and from whom consent has been obtained / or a consultee has consented on he subjects behalf in line with nationally agreed guidelines concerning adults unable to consent for themselves.

Exclusion Criteria:

* Presence of nasogastric / nasojejunal feeding tube at the time of VFSS test
* Currently has a tracheostomy, or has had a tracheostomy in the past year
* Had posterior cervical spine surgery and/or carotid endarterectomy in the last 6 months
* Had significant surgery to the mouth and/or neck, for example resection for oral or pharyngeal cancer, radical neck dissection, anterior cervical spine surgery, orofacial reconstruction, pharyngoplasty, or thyroidectomy. Routine tonsillectomy and/or adenoidectomy are not excluded
* Experienced non-surgical trauma to the neck (e.g., knife wound) resulting in musculoskeletal or nerve injury in the neck.
* Received radiation or chemotherapy to the oropharynx or neck for cancer.
* Allergy to oral radiographic contrast media (specifically barium)
* Distorted oropharyngeal anatomy (e.g. pharyngeal pouch)
* Cognitive impairment that prevents them from being able to comply with study instructions and procedures
* Known to be pregnant at the time of enrollment
* Currently has significant facial hair at the location of sensor adherence and are unwilling/unable to be shaved
* Any patients the local investigator finds that participation would not be in patients' best interest