Diagnosis and Clinical Course of Unexplained Dysphagia

OBJECTIVE: To investigate the final diagnosis of patients with unexplained dysphagia and the clinical and laboratory findings supporting the diagnosis. METHODS: We retrospectively analyzed 143 patients with dysphagia of unclear etiology who underwent a videofluoroscopic swallowing study (VFSS). The medical records were reviewed, and patients with a previous history of diseases that could affect swallowing were categorized into a missed group. The remaining patients were divided into an abnormal or normal VFSS group based on the VFSS findings. The clinical course and final diagnosis of each patient were examined. RESULTS: Among the 143 patients, 62 (43%) had a previous history of diseases that could affect swallowing. Of the remaining 81 patients, 58 (72.5%) had normal VFSS findings and 23 (27.5%) had abnormal VFSS findings. A clear cause of dysphagia was not identified in 9 of the 23 patients. In patients in whom a cause was determined, myopathy was the most common cause (n=6), followed by laryngeal neuropathy (n=4) and drug-induced dysphagia (n=3). The mean ages of the patients in the normal and abnormal VFSS groups differed significantly (62.52±15.00 vs. 76.83±10.24 years, respectively; p<0.001 by Student t-test). CONCLUSION: Careful history taking and physical examination are the most important approaches for evaluating patients with unexplained swallowing difficulty. Even if VFSS findings are normal in the pharyngeal phase, some patients may need additional examinations. Electrodiagnostic studies and laboratory tests should be considered for patients with abnormal VFSS findings.

Validation of Attitude and Heading Reference System and Microsoft Kinect for Continuous Measurement of Cervical Range of Motion Compared to the Optical Motion Capture System

OBJECTIVE: To compare optical motion capture system (MoCap), attitude and heading reference system (AHRS) sensor, and Microsoft Kinect for the continuous measurement of cervical range of motion (ROM). METHODS: Fifteen healthy adult subjects were asked to sit in front of the Kinect camera with optical markers and AHRS sensors attached to the body in a room equipped with optical motion capture camera. Subjects were instructed to independently perform axial rotation followed by flexion/extension and lateral bending. Each movement was repeated 5 times while being measured simultaneously with 3 devices. Using the MoCap system as the gold standard, the validity of AHRS and Kinect for measurement of cervical ROM was assessed by calculating correlation coefficient and Bland–Altman plot with 95% limits of agreement (LoA). RESULTS: MoCap and ARHS showed fair agreement (95% LoA10°) for measuring ROM in all directions. Intraclass correlation coefficient (ICC) values between MoCap and AHRS in –40° to 40° range were excellent for flexion/extension and lateral bending (ICC>0.9). ICC values were also fair for axial rotation (ICC>0.8). ICC values between MoCap and Kinect system in –40° to 40° range were fair for all motions. CONCLUSION: Our study showed feasibility of using AHRS to measure cervical ROM during continuous motion with an acceptable range of error. AHRS and Kinect system can also be used for continuous monitoring of flexion/extension and lateral bending in ordinary range.