Social perception of emotions from facial expressions

A chief element in social interaction is the ability to recognize facial expressions and their emotional significance (Brothers, Reference Brothers1990; Van Kleef, Reference Van Kleef2009). A large-scale network and a complex processing have been suggested by this skill. The first step consists of early visual processing of faces, which entails a relatively shared neural pathway for facial identity discrimination and facial emotion recognition (Calder & Young, Reference Calder and Young2005; LaBar, Crupain, Voyvodic, & McCarthy, Reference LaBar, Crupain, Voyvodic and McCarthy2003; Palermo & Rhodes, Reference Palermo and Rhodes2007; Vuilleumier & Pourtois, Reference Vuilleumier and Pourtois2007). In the following steps, distinct cortical regions would intervene. For instance, the fusiform face area (FFA) plays a key role in recognizing invariant or neutral facial aspect that defines identity (Kanwisher & Yovel, Reference Kanwisher and Yovel2006). Other areas, such as the superior temporal sulcus (STS), are more specialized in changeable facial features (i.e., perception of eyes and mouth movements; Allison, Puce, & McCarthy, Reference Allison, Puce and McCarthy2000). The amygdala is an essential element in automatic attentional capture by emotionally relevant facial expressions (Vuilleumier & Pourtois, Reference Vuilleumier and Pourtois2007). The orbitofrontal cortex (OFC) is crucially involved in processing non-conscious aspects of facial expressions (Adolphs, 2006; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009). To note, non-conscious perception of emotional stimuli is an intrinsic property of the healthy brain. Through this process, emotionally relevant visual stimuli that are not perceived consciously can induce behavioral responses manifesting as changes in emotional states (Tamietto & de Gelder, Reference Tamietto and de Gelder2010).

Of interest, observing facial emotions is known to trigger an affective reaction which subsequently leads to adaptive changes in the observer’s behavior (Van Kleef, Reference Van Kleef2009). Such a reaction depends on the generation of an “emotional state” and a “motivation state.” The former is mainly created by the anterior insula that integrates environmental cues with viscero-reception of internal body state (Adolphs, Reference Adolphs2002). The latter is completed via the action of the anterior cingulate cortex (ACC; Critchley, Reference Critchley2005).

Social perception of vocal cues: Affective prosody

Prosody is an aspect of language represented by acoustic characters such as the pattern of intonation (i.e., timing, pitch, rhythm, stress, and pausing; Heikkinen et al., Reference Heikkinen, Jansson-Verkasalo, Toivanen, Suominen, Vayrynen, Moilanen and Seppanen2010; Uekermann & Daum, Reference Uekermann and Daum2008; Uekermann, Abdel-Hamid et al., Reference Uekermann, Abdel-Hamid, Lehmkamper, Vollmoeller and Daum2008). Among the subdivisions of prosody, the most relevant here are the linguistic and affective components (Ross et al., Reference Ross, Thompson and Yenkosky1997; Uekermann & Daum, Reference Uekermann and Daum2008). While processing linguistic prosody seems to involve left-sided brain regions, perception of affective prosody is a dominant function of the right hemisphere and encompasses many steps (Ethofer et al., Reference Ethofer, Anders, Erb, Herbert, Wiethoff, Kissler and Wildgruber2006; Uekermann & Daum, Reference Uekermann and Daum2008; Uekermann, Abdel-Hamid, et al., Reference Uekermann, Abdel-Hamid, Lehmkamper, Vollmoeller and Daum2008; Wildgruber, Ackermann, Kreifelts, & Ethofer, Reference Wildgruber, Ackermann, Kreifelts and Ethofer2006).

For example, primary and higher order right-hemispheric acoustic areas deal with extracting suprasegmental acoustic information whose meaningful representation mainly involves the right STS. Bilateral inferior frontal regions maintain an explicit assessment of affective prosody. Lastly, the corpus callosum (CC) participates by ensuring the inter-hemispheric integration of language functions (Ross et al., Reference Ross, Thompson and Yenkosky1997); this seems crucial to understanding emotional prosody, especially when the latter is not in agreement with the linguistic component. In this situation, a proper understanding requires a successful prioritization of the affective aspect over the linguistic one (Uekermann et al., Reference Uekermann, Kraemer, Abdel-Hamid, Schimmelmann, Hebebrand, Daum and Kis2010).

Social perception of facial emotions in multiple sclerosis

In the past two decades, there was a growing interest in understanding the abilities of MS patients to recognize emotional facial expressions (EFE). The earliest insight into this topic came from a pioneering study by Beatty and colleagues (Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989). Patients with chronic progressive MS and age and education matched healthy controls (HCs) performed the Benton Facial Recognition Test (BFRT) for facial identity discrimination (Benton, Sivan, Hamsher, Varney, & Spreen, Reference Benton, Sivan, Hamsher, Varney and Spreen1994) and an affective judgment task that evaluates the ability to recognize the six basic facial emotions (i.e., happiness, sadness, anger, fear, disgust and surprise; Ekman and Friesen, Reference Ekman and Friesen1976).

Compared to HCs, patients had worse cognitive performance and lower accuracy in both facial identity discrimination and facial emotion recognition. The deficits in emotion recognition were not restricted to a particular emotional state. Furthermore, correlation analysis revealed a positive correlation between scores on BFRT and those on affective judgment task. This made the authors consider the observed deficits in EFE recognition as secondary to those in facial identity discrimination which can somewhat reflect visuoperceptual deficits. Concurrently, the authors included a group of RR MS patients who, unlike their progressive counterparts, had preserved abilities to recognize EFE but were “slightly” impaired on BFRT test. Based on these findings, one would assume that clinical and demographic differences between both patient groups accounted for the observed differences in recognizing EFE. Unfortunately, the RR MS group was not included in the remaining statistical analyses.

Consistent with the first report, Parada-Fernández et al. considered a mixed cohort of RR and progressive MS patients and healthy subjects (2015). The authors used BFRT and Facially Expressed Emotion Labeling task (Kessler, Bayerl, Deighton, & Traue, Reference Kessler, Bayerl, Deighton and Traue2002) which, respectively, evaluate facial identity discrimination and facial emotion recognition. To further eliminate any bias that might result from visual impairment, the authors excluded patients who had visual difficulties which disable them from reading and/or writing. This study showed that patients had difficulties in facial emotion recognition and identity discrimination. Moreover, a stepwise multiple regression analysis revealed that disease type and non-social cognitive abilities were the main contributors to the observed deficits in recognizing EFE. Facial identity discrimination did not seem to contribute to social cognitive deficits in this study.

Similarly, Berneiser et al. applied the facial affect task of Florida Affect Battery (Bowers, Blonder, & Heilman, Reference Bowers, Blonder and Heilman1991, Reference Bowers, Blonder and Heilman2001) to evaluate EFE recognition abilities in patients with different MS subtypes and HCs (2014). Compared to HCs, patients had worse performance in all subsets of the facial affect task, even after exclusively considering those with intact abilities to discriminate facial identity. This stands with what Parada-Fernández et al. stated (Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015) and is against the earlier suggestion by Beatty et al. (Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989). Again, Berneiser et al. found more pronounced deficits among SP MS patients compared to those suffering from RR MS. In addition, emotion recognition scores were directly correlated with cognitive performance and indirectly correlated with each of depression and fatigue scores, disease duration, and level of physical disability based on the Expanded Disability Status Scale score (EDSS).

Analogously, in the study by Cecchetto et al., patients had poorer performance than HCs on tasks assessing the recognition of all of the six basic facial emotions but had intact abilities to discriminate facial identity (2014). When patients were subdivided based on physical disability (EDSS scores), only highly disabled ones were impaired in labeling EFE. The latter was further correlated with disease characteristics (i.e., disease duration and EDSS scores) and non-social cognitive performance.

In the same perspective, Phillips et al. have assessed emotions’ recognition skills using static (Ekman & Friesen, Reference Ekman and Friesen1976) and dynamic measures (videos featuring frustration, excitement, annoyance, and boredom by Sullivan & Ruffman, Reference Sullivan and Ruffman2004) (2011). Compared to HCs, patients had worse mood and cognitive scores and showed deficits in recognizing facial emotions without differences in facial identity discrimination. The deficits remained significant even after accounting for depression and cognitive decline. In addition, EFE recognition was associated with social and psychological aspects of QoL (Phillips et al., Reference Phillips, Henry, Scott, Summers, Whyte and Cook2011).

Unlike the above-mentioned studies that brought out social cognitive deficits in all of the six basic facial emotions, others rather found an isolated pattern of impairment in recognizing EFE. For instance, two MS trials documented exclusive deficits in identifying the emotions “fear” and “anger” (Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011). These results are in line with those of a third study comparing HCs and two groups of MS patients with or without altered abilities to recognize EFE (Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009). Here, compared to HCs and the preserved MS group, affected patients had deficits in recognizing “sadness,” “fear,” and “anger” but were able to discern positive emotions. Moreover, in a fourth study, patients with intact abilities to discriminate facial identity had significant impairment in identifying “fear,” “sadness,” “anger,” and “surprise” (Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011). More interestingly, when considering physical disability as a variable, severely disabled patients had worse cognitive performance and displayed an additional deficit in the emotion “disgust.” Thus, higher disability levels seem to contribute to the emergence of other deficits.

The isolated involvement of negative emotions in the latter studies (Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011) might be explained as follows: One of the possibilities is that positive emotions might be relatively easier to process than negative ones and could hence be more compensated (Skowronski & Carlston, Reference Skowronski and Carlston1989). This idea is supported by one MS study in which “happiness,” for example, was better recognized than “fear” or “sadness” (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014). Another reason is that MS patients might express low sensitivity toward aversive stimuli (Di Bitonto et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011). Indeed, these patients were found to have reduced emotional reactivity to negative stimuli (i.e., sounds and pictures) compared to HCs but had normal reactivity to positive ones (Di Bitonto et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011).

Functional neuroimaging data can provide a third explanation. In fact, the normal processing of each emotion seems to induce a selective pattern of brain activation (Jehna, Neuper, et al., Reference Jehna, Neuper, Ischebeck, Loitfelder, Ropele, Langkammer and Enzinger2011). For example, some cerebral areas (i.e., VLPFC, ACC, and superior temporal gyri) are more activated during processing of “sadness,” while others (i.e., DLPFC, cingulate gyrus, inferior temporal gyrus, and cerebellum) appear to be more specific for “happiness” (Habel, Klein, Kellermann, Shah, & Schneider, Reference Habel, Klein, Kellermann, Shah and Schneider2005). This idea can be exemplified by one fMRI study in MS where the selective deficit in recognizing negative emotions was associated with hypoactivation of cortical areas devoted to processing negative emotions (i.e., ACC, fSTS, and VLPFC) (Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009).

Finally, five studies found intact EFE recognition abilities in MS patients (Di Bitonto et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010; Jehna, Langkammer, et al., Reference Jehna, Langkammer, Wallner-Blazek, Neuper, Loitfelder, Ropele and Enzinger2011; Passamonti et al., Reference Passamonti, Cerasa, Liguori, Gioia, Valentino, Nisticò and Fera2009; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012). This is not surprising given that four of them recruited exclusively (Passamonti et al., Reference Passamonti, Cerasa, Liguori, Gioia, Valentino, Nisticò and Fera2009; Jehna, Langkammer, et al., Reference Jehna, Langkammer, Wallner-Blazek, Neuper, Loitfelder, Ropele and Enzinger2011; Di Bitonto et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011) or predominantly (Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012) RR MS patients. Once more, the cohort of the fifth study consisted mostly of preserved patients with clinically isolated syndrome and RR MS (Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010). Here, the authors assessed the accuracy and reaction time during EFE recognition task. Although accuracy did not differ between both groups, patients were slower than HCs. The observed slowing might not reflect deficits in emotion recognition, but could rather hint to a general delay in IPS which is frequent in MS (Vázquez-Marrufo et al., Reference Vázquez-Marrufo, Galvao-Carmona, González-Rosa, Hidalgo-Muñoz, Borges, Ruiz-Peña and Izquierdo2014) or an age-related slowing (Knight & Mather, Reference Knight and Mather2013) since HCs were significantly younger than patients.

The above-mentioned studies are summarized in Table 1. The differences in their outcomes might be explained by the disparity in clinical and demographic characteristics of their cohorts (e.g., Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014; Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011), differences in adopted assessment tools (dynamic vs. static tasks) and presence of confounding variables such as mood and affective disturbances, cognitive deficits, and MS fatigue, all of which might contribute to deficits in identifying EFE.

Starting with disease characteristics, patients with higher physical disabilities seem to be the most affected on tasks assessing EFE recognition (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011). In this context, some studies were for a correlation between EDSS scores (Kurtzke, Reference Kurtzke1983) and deficits in judging EFE (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014), while others denied it (Henry et al., Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010). As for disease subtypes, progressive MS patients seem to suffer from more pronounced deficits compared to RR MS patients (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010; Jehna, Langkammer, et al., Reference Jehna, Langkammer, Wallner-Blazek, Neuper, Loitfelder, Ropele and Enzinger2011; Parada-Fernández et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015; Passamonti et al., Reference Passamonti, Cerasa, Liguori, Gioia, Valentino, Nisticò and Fera2009; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012). Regarding disease duration, it was found to be associated with deficits in labeling EFE in some (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014) but not all studies (Henry et al., Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010).

Facial identity discrimination remains the main confounding variable in the recognition of EFE (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Di Bitonto et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012) since both processes share early common neural processing pathways. Although some MS studies suggest that deficits in the former be behind those in the latter (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Di Bitonti et al., Reference Di Bitonto, Longato, Jung, Fleury, Marcel, Collongues and Blanc2011), most of the remaining data are not in favor of this assumption (Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014; Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Parada-Fernández et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015; Phillips et al., Reference Phillips, Henry, Scott, Summers, Whyte and Cook2011; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011).

MS fatigue is another frequent symptom that can be defined as a reversible alteration of cognitive task performance (Chalah et al., Reference Chalah, Riachi, Ahdab, Créange, Lefaucheur and Ayache2015). Up until now, only a few studies evaluated its relationship with EFE recognition. While one study found it to be associated with EFE task performance (Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014), others were not able to detect any significant relationship (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Henry et al., Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011).

Importantly, an interaction was previously found among emotions, mood, and cognition (Leppanen, Reference Leppanen2006; Pessoa, 2008). In some studies, MS patients with deficits on EFE recognition tasks had also high depression scores (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014; Henry et al., Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Parada Fernandez et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015; Phillips et al., Reference Phillips, Henry, Scott, Summers, Whyte and Cook2011; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011) and poor cognitive abilities (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Parada-Fernández et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015; Phillips et al., Reference Phillips, Saldias, McCarrey, Henry, Scott, Summers and Whyte2009; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011). However, the correlation of EFE recognition with cognitive and mood scores remains controversial. While some studies are in favor of this relationship (Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014; Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010; Parada-Fernández et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012), others failed to detect any significant association (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014; Henry et al., Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011).

Alexithymia is an additional variable that might interfere here (Grynberg et al., Reference Grynberg, Chang, Corneille, Maurage, Vermeulen, Berthoz and Luminet2012). By definition, it is a personality trait characterized by difficulties in emotional identification, understanding, and description (Franz et al., Reference Franz, Popp, Schaefer, Sitte, Schneider, Hardt and Braehler2008). Alexithymia was tackled in two MS trials evaluating EFE recognition. Although one of them featured higher levels of alexithymia in MS patients compared to HCs (Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011), the other did not find any group difference (Cecchetto et al., Reference Cecchetto, Aiello, D’Amico, Cutuli, Cargnelutti, Eleopra and Rumiati2014), and neither of them detected an association between alexithymia and deficits in EFE recognition.

All in all, deficits in facial emotion recognition might occur early during MS, and do not seem to be restricted to progressive disease subtypes. However, disease characteristics and concomitant symptoms may contribute to such deficits. Heterogeneity in MS lesions location might be behind the different patterns of EFE recognition deficits encountered in various studies. One might speculate that during disease course, clinical and radiological MS progression can also be mirrored by a shift from an intact abilities to recognize EFE (Jehna et al., Reference Jehna, Neuper, Petrovic, Wallner-Blazek, Schmidt, Fuchs and Enzinger2010, Jehna, Langkammer, et al., Reference Jehna, Langkammer, Wallner-Blazek, Neuper, Loitfelder, Ropele and Enzinger2011; Passamonti et al., Reference Passamonti, Cerasa, Liguori, Gioia, Valentino, Nisticò and Fera2009; Pinto et al., Reference Pinto, Gomes, Moreira, Rosa, Santos, Silva and Cavaco2012), to an isolated pattern of deficits (Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011), and finally to a global deficit (Beatty et al., Reference Beatty, Goodkin, Weir, Staton, Monson and Beatty1989; Berneiser et al., Reference Berneiser, Wendt, Grothe, Kessler, Hamm and Dressel2014; Parada-Fernández et al., Reference Parada-Fernández, Oliva-Macias, Amayra, Lopez-Paz, Lazaro, Martinez and Perez2015).

Social perception of affective prosody in multiple sclerosis

In advanced MS stages, visual deficits can become very pronounced, and patients might depend on the perception of affective prosody for a successful social interaction. Only two MS studies have addressed this issue. In the first one, the authors used the comprehension and discrimination portions of Aprosodia battery (Ross et al., Reference Ross, Thompson and Yenkosky1997) in a cohort of chronic MS patients (Beatty, Orbelo, Sorocco, & Ross, Reference Beatty, Orbelo, Sorocco and Ross2003). Compared to HCs, patients had worse performance on affective prosody, mood, and cognitive scales. Measures of affective prosody were positively correlated with cognitive scores but were not associated with mood disturbance, hearing loss, aphasia, treatment profile, or education. Unfortunately, patients’ clinical characteristics were not provided and their impact on prosody was not assessed.

In contrast with the first study, the second one included patients with early stage of RR MS (Kraemer, Herold, Uekermann, Kis, et al., Reference Kraemer, Herold, Uekermann, Kis, Daum, Wiltfang and . . .Abdel-Hamid2013). Compared to HCs, patients had higher depression scores but did not differ on most of the cognitive scores. They poorly discriminated affective prosody, had lower accuracy in matching affective prosody to the facial expression for “anger,” but were able to recognize “happiness.” This finding is in line with the isolated pattern of deficits seen in some EFE studies (anger and fear in Henry et al., Reference Henry, Phillips, Beatty, McDonald, Longley, Joscelyne and Rendell2009, Reference Henry, Tourbah, Chaunu, Rumbach, Montreuil and Bakchine2011; anger, sadness, and fear in Krause et al., Reference Krause, Wendt, Dressel, Berneiser, Kessler, Hamm and Lotze2009; anger, sadness, fear, and surprise in Prochnow et al., Reference Prochnow, Donell, Schäfer, Jörgens, Hartung, Franz and Seitz2011). The observed deficits were unrelated to mood, cognitive performance, or physical disability. Unlike the cohort examined by Beatty et al. (Reference Beatty, Orbelo, Sorocco and Ross2003), patients seen here performed better than HCs on matching affective prosody to facial expression for the emotion “fear.” This finding might be due to an increased sensitivity for recognizing “fear” in a population of young patients recently shocked by the diagnosis of a chronic disabling disease such as MS (Kraemer, Herold, Uekermann, Kis, et al., Reference Kraemer, Herold, Uekermann, Kis, Daum, Wiltfang and . . .Abdel-Hamid2013).