Expression and Perception of Nonverbal Cues to Mood in Parkinson’s Disease

PURPOSE: To investigate the convergence between nonverbal cues that express mood in people with Parkinson’s disease (PD) and the nonverbal cues that observers use to perceive their mood.

BACKGROUND: PD, a neurodegenerative movement disorder characterized by a paucity of movement, can affect a person’s ability to communicate nonverbally in the face (facial masking) and body in a way that people find readable. These changes to nonverbal expressivity may lead to people with PD being misunderstood or negatively perceived by their peers and also practitioners.

Previous research has shown that people with PD do not express many nonverbal cues to their personality, but little is known about the expression and perception of mood in PD. This is important because detecting mood is fundamental in adjusting rehabilitation plans and establishing therapeutic rapport in clinical practice.

DESIGN: Observational and correlational analysis of people with PD from a database of participants who agreed to have their data used for future research

PARTICIPANTS: Ninety-six individuals (mean age = 66.46, standard deviation = 9.07) with PD who had a Hoehn and Yahr disease severity stage between 2 and 3.

METHOD: As part of a previous study, participants were videotaped while discussing an enjoyable activity and then reported their mood using the Positive and Negative Affect Schedule (PANAS). These videotapes were coded for 12 nonverbal expressive cues in the face and body.

In the current study, 5 occupational therapy graduate student research assistants inferred the mood of participants from a 20-s video clip of the participants’ enjoyable activity narrative with no sound and then used the PANAS to rate each participant’s mood. The videos were watched without sound, so raters were blind to the content of the speech, and raters were also blind to disease severity. The student raters showed good interrater reliability with a mean intraclass correlation of r =.73, indicating their ratings were generalizable to other similar raters.

ANALYSIS: Correlational analyses were conducted to determine (1) the nonverbal cues that were valid indicators of participants’ moods, (2) the nonverbal cues expressed by participants that raters used to make their inferences, and (3) the congruence between the cues participants used to display mood and the cues raters used to infer mood.

RESULTS: Overall, participants who raised their cheeks more, r(94) = .37, p < .01, and smiled more, r(94) = .29, p < .01, projected a more positive mood to the observers, and participants with more facial masking projected less of a positive mood, r(94) = –.22, p < .05, but none of these cues were correlated with participants’ actual reported affect. There was greater congruence between participants’ and raters’ use of cues for negative mood, r(10) = .67, p < .05, than positive mood, r(10) = .45, p >.05.

DISCUSSION: We found that PD mood state was difficult to judge accurately. Participants did not display many cues to their mood, and thus raters tended to use many more expressive cues in making their judgments than were actually valid cues to mood. These findings are similar to previous findings about enduring psychological and personality traits. We also found it was harder to judge positive mood than negative mood. Therefore, observers may not recognize when people with PD have a positive mood.

IMPACT STATEMENT: These findings emphasize the importance of helping clients with PD to be able to produce verbal and nonverbal cues that can be accurately interpreted by others, as well as pointing to the need for observers, especially practitioners, to be trained about their own implicit biases in using cues incorrectly in people with movement disorders.