Social cognition in mood disorders – Part III: prosody in Major Depression and Bipolar Disorder
With regard to Mood Disorders, the international scientific literature shows that patients with Major Depression show a compromise in the recognition of emotions conveyed through prosody, while as regards Bipolar Disorder the literature reports substantially similar results both as regards the emotional processing conveyed through the expression of the faces and with regard to the capacity for emotional recognition through prosody.
Social Cognition in Mood Disorders – Prosody in Major Depression and Bipolar Disorder (Nr. 3)
Advertising message As is known, a correct interpretation of the other’s signals, in this case with an emotional content, is fundamental for the proper functioning of social interactions. From an acoustic point of view, the relevant signals from a social cognition point of view can be expressed verbally, in semantic mode, or non-verbally, in prosodic mode, which are generally perceived as a more reliable source of information about the feelings of the other ( Jacob et al., 2013a, 2013b, Koch et al, 2018). In our psychotherapy settings, this ability can be assessed through the history and clinical behavioral observation of our patients, such as the ability, during the interview, to convey emotions through facial expression, gestures, voice, body language. ,
From a neuroanatomical point of view, prosody is expressed in a neural circuit located mainly in the right hemisphere, in particular in the upper temporal region, in the lobe and in the posterior regions of the temporal sulcus, respectively as regards the perception and abstraction of the auditory information and the process of representing meaning of what is heard. The evaluation of the emotional content of prosody seems instead mediated by the bilateral lower frontal cortex (Wildgruber et al., 2004; 2005; 2006; Ross, 1981; Buchanan et al., 2000; Kotz et al., 2003; Mitchell et al., 2003).
The literature proposes a model according to which lesions of the right hemisphere, in correspondence of the left areas responsible for the classic aphasias, can determine disturbances in prosody with an emotional value. Specifically, it is pointed out that a lesion in the right temporal-parietal region can express itself in an aprosody in the receptive function, while a lesion in the region of the frontal operculum, in the cortex and in the white matter, can produce an alteration of the prosody in its function. expressive (Ross, 2000).
With regard to Mood Disorders, the international scientific literature shows that patients with Major Depression show greater compromise, compared to the control sample of healthy subjects, in the recognition of emotions conveyed through prosody (Wildgruber et al, 2004; Uekermann et al ., 2008).
As already studied in depth regarding the processing of facial emotions (Part I and Part II of this section; for a complete review see Cusi et al. 2012, Turchi et al., 2017), also in this case there is a distorted interpretation of neutral emotions, such as surprise, valued rather as negative emotions (Naranjo et al., 2011; Kan et al., 2004) as well as impairments in the ability to identify emotions, both negative and positive, through the tone of voice (Wildgruber et al., 2006; Ross, 1981). In fact, in these patients there is a tendency to underestimate emotional information with a positive value (Schlipf et al., 2013) as well as a compromise in the processing of sadness and an alteration in the recognition of emotions with a negative value, always expressed through the prosodic channel (Pang et al. 2014; Peron et al., 2011). These compromises do not seem to correlate with the severity of the depressive symptoms and have therefore been proposed as a possible trait alteration, characteristic of the disorder (Schlipf et al, 2013; Pang et al., 2014).
Advertising message Also online a very recent study which, for the first time, has examined the explicit evaluation of emotional contents expressed through the prosody channel both at a neural and behavioral level, which concludes for a distorted attribution, in patients with Depression greater compared to the control sample of healthy subjects, dependent on prosodic emotions with a positive value. The study also shows an increased activation of the amygdala, bilaterally, in the processing of prosodic emotional information, probably associated with compromised emotional regulation strategies in subjects with Major Depression, already widely known in the literature. According to the authors, the greater activation of the amygdala, in this sense, it could be interpreted as an attempted compensation mechanism with respect to the distortion in the elaboration of stimuli with emotional content, in order to favor a more accurate perception. At the same time, however, the altered perception of emotions with a positive value, characteristic of the Major Depressive Episode (Cusi et al, 2012; Turchi et al. 2016; 2017), contributes to maintaining the depressive symptomatology in place, effectively hindering the recovery attempt (Koch et al., 2018).
As regards Bipolar Disorder, the literature reports substantially similar results, both as regards the emotional processing conveyed through the expression of the faces (Cusi et al. 2012, Turchi et al., 2016) and as regards the ability to recognize emotional through prosody (Murphy & Cutting, 1990; Bozikas et al. 2007). We will deal with any specific differences from a neurofunctional point of view in the next part of the section.
The subjects with Bipolar Disorder in this case, as well as those diagnosed with Schizophrenia, compared with healthy controls, show less activation of the amygdala, of the bilateral superior temporal gyrus, of the hippocampus hook and of the lower right frontal gyrus, during passive listening of vocal intonation conveying a clearly emotional content, as well as an increase in neurofunctional activation in the upper left temporal gyrus during the processing of unfiltered emotional prosodic stimulus. The fact that there is no activation in the prefrontal and temporal areas of the right hemisphere, essential for the recognition function of the prosody with emotional content, suggests a compromise, at a neural level, in the ability to process this stimulus ( Mitchell et al., 2004).
To date, there are no studies regarding the influence of mood, pharmacotherapy treatment, age and history of disease on the neural response in developing prosodic stimuli with emotional content, for which the subject deserves further study.
From our point of view, understanding these aspects would be very important since a good overall functioning of the patient, including the social dimension, a fundamental aspect that affects the life of each of us from both an emotional and professional point of view, is directly linked to quality of perceived life and the likelihood of relapsing into a new episode of mood. Starting to consider Social Cognition skills (Couture, Penn and Roberts, 2006), including those conveyed by prosody, could therefore be very useful in the psychotherapy work with people with Mood Disorders, to try to evaluate and improve the overall functioning of the person and, in this way, to prevent relapse as much as possible which, in turn, as known, leads to greater compromises in several respects. In fact, given the psychopathological complexity of these disorders, it is now necessary to carry out an evaluation and planning of the evidence-based intervention that does not disregard the person’s epigenetic path.