Neurological Disorders

Encoding and Assessing Sung Melodies in Stroke Patients with Aphasia

Abstract

Anthony Androulakis

Aphasia is a language and communication disorder caused by damage to the brain, usually occurring after stroke or traumatic brain injury. Two MATLAB computer programs are presented for encoding and assessing the sung melodies of stroke patients. The first MATLAB program, Sung Melody to Matrix (SMM.m), converts a patient’s sung melody into a matrix containing the frequency and corresponding duration of each note sung. To find when the patient moves from one note to another, a novel method called Visual Audio Signal Envelope (VASE) is used, which determines an audio signal’s envelope through visual cues. Other existing envelopes that were tested did not work as well with the voice of post-stroke patients recorded in a noisy environment. The second MATLAB program, Melodic Fidelity Evaluator (MFE.m), compares this matrix to the matrix of the tune that the patient was trying to imitate. This second program provides a fair assessment of the note interval error and the time interval error of the patient. In addition, these programs are easy-to-use and can be automated for large data sets to correlate with brain lesions in stroke patients.