Case Study: Differential Effects of Melody and Rhythm in Melodic Intonation Therapy

Abstract

The purpose of the current observational study was to explore differential effects of melody-only condition and rhythmic left-hand tapping-only condition in Melodic Intonation Therapy, when accompanied with formulaic words or phrase and slow rate. The participant included a 77-year-old, monolingual, non-Hispanic, Caucasian male with severe Broca’s aphasia enrolled at a university clinic. The independent variable was the individual component of MIT, with two conditions: (1) melody only and (2) rhythm and left-hand tapping only. The dependent variable was percentage accuracy of the participant’s ability to repeat a list of targets (i.e., pre-selected formulaic words/phrases). An alternating treatment design over two treatment phases was used in the present study. The percentage of nonoverlapping data was calculated by dividing the number of treatment sessions exceeding the highest data point during baseline sessions by the total number of treatment sessions. Results indicated that melody-only condition was a fairly effective treatment while rhythm and left-hand tapping-only condition was an unreliable treatment. The participant had difficulty following rhythm and left-hand tapping possibly due to a rhythm-processing deficit. Motivation and mood effect of singing in unison might positively influence the accuracy of repetitions in the participant. Limitations of the study were discussed. Keywords: Melody; Rhythm; Formulaic speech; Melodic Intonation Therapy (MIT); Broca’s aphasia