Clinical investigations of receptive and expressive musical functions after stroke

Abstract

There is a long tradition of investigating various disorders of musical abilities after stroke. These impairments, associated with acquired amusia, can be highly selective, affecting only music perception (i.e., receptive abilities/functions) or expression (music production abilities), and some patients report that these may dramatically influence their emotional state. The aim of this study was to systematically test both the melodic and rhythmic domains of music perception and expression in left- and right-sided stroke patients compared to healthy subjects. Music perception was assessed using rhythmic and melodic discrimination tasks, while tests of expressive function involved the vocal or instrumental reproduction of rhythms and melodies. Our approach revealed deficits in receptive and expressive functions in stroke patients, mediated by musical expertise. Those patients who had experienced a short period of musical training in childhood and adolescence performed better in the receptive and expressive subtests compared to those without any previous musical training. While discrimination of specific musical patterns was unimpaired after a left-sided stroke, patients with a right-sided stroke had worse results for fine melodic and rhythmic analysis. In terms of expressive testing, the most consistent results were obtained from a test that required patients to reproduce sung melodies. This implies that the means of investigating production abilities can impact the identification of deficits.

Keywords: amusia; expressive function; music perception; music production; receptive function.

FIGURE 1

Examples of receptive and expressive subtests.

FIGURE 2

Correct answers (mean values) of patients and controls for Metre Test 1 vs. Metre Test 2 (error bars indicate one standard deviation).

FIGURE 3

Correct answers (mean values) of left- and right-sided stroke patients for Melody Interval Test vs. Rhythm Test (error bars indicate one standard deviation).

FIGURE 4

Sum scores of patients with musical education and patients without for Expressive Rhythm Tests vs. Expressive Melody Tests (error bars indicate one standard deviation).

FIGURE 5

Sum scores of patients and controls for expressive production by xylophone vs. singing (error bars indicate one standard deviation).