Beyond Face and Voice: A Review of Alexithymia and Emotion Perception in Music, Odor, Taste, and Touch

Advancements in Sensors and Analyses for Emotion Sensing

Exploring the objective signals associated with subjective emotional states has practical significance [...].

Alexithymia modulates emotion concept activation during facial expression processing

Alexithymia is characterized by difficulties in emotional information processing. However, the underlying reasons for emotional processing deficits in alexithymia are not fully understood. The present study aimed to investigate the mechanism underlying emotional deficits in alexithymia. Using the Toronto Alexithymia Scale-20, we recruited college students with high alexithymia (n = 24) or low alexithymia (n = 24) in this study. Participants judged the emotional consistency of facial expressions and contextual sentences while recording their event-related potentials. Behaviorally, the high alexithymia group showed longer response times versus the low alexithymia group in processing facial expressions. The event-related potential results showed that the high alexithymia group had more negative-going N400 amplitudes compared with the low alexithymia group in the incongruent condition. More negative N400 amplitudes are also associated with slower responses to facial expressions. Furthermore, machine learning analyses based on N400 amplitudes could distinguish the high alexithymia group from the low alexithymia group in the incongruent condition. Overall, these findings suggest worse facial emotion perception for the high alexithymia group, potentially due to difficulty in spontaneously activating emotion concepts. Our findings have important implications for the affective science and clinical intervention of alexithymia-related affective disorders.

[The sound and musical preferences of tympanic chord]

The tympanic chord is a part of the 7th cranial nerve (facial nerve), from which it branches off, runs through the middle ear and then joins the lingual nerve, a part of the 5th cranial nerve (mandibular nerve/trigeminal nerve). Despite its course through the ear, the tympanic chord does not carry auditory fibers, but rather sensory and parasympathetic fibers to the front part of the tongue and to the salivary glands.The cranial nerves V and VII have a common phylogenetic origin, establishing a close relationship between auditory and gustative sense.In German language "Geschmack" means both gustative sense and the preference for different ways of thinking or styles in music, art or fashion. "Musikgeschmack" is the preference for special music styles or composers. "Musikgeschmack" therefore forms an interface between the anatomy of the tympanic chord and music preferences.The effect of parallel processing of music and taste is used, for example, in music therapy or as part of marketing strategies. But it could also be used to treat Covid-19 patients who suffer from a loss of sense of smell and taste. However, there are still no studies on this specific question.

Alexithymia modulates the attitudes towards odors but not the olfactory abilities or the affective reactions to odors

Although emotion and olfaction are closely linked, only a few studies have investigated olfactory processing in alexithymia, a condition characterized by altered emotional processing. These results do not allow comprehensive conclusions on whether individuals with alexithymia present lower olfactory abilities or only altered affective reactions and awareness of odors. Three pre-registered experiments were conducted to clarify this relation. We assessed olfactory functions, the affective qualities of odors, the awareness of odors, the attitudes towards them, and the ability to form olfactory images in the mind. Bayesian statistics were used to assess differences between low, medium and high alexithymia groups, and Linear Mixed Models (LMMs) were applied to investigate the modulation of the affective and cognitive components of alexithymia. We observed that individuals with a high level of alexithymia presented the same olfactory abilities, and did not show differences in their rating of odors compared to individuals with low alexithymia levels, while they reported lower levels of social and common odor awareness and a more indifferent attitude towards odors. Olfactory imagery was not affected by alexithymia level, and the affective and cognitive components of alexithymia, when considered separately, modulated olfactory perception differently. Learning more about olfactory perception in individuals with alexithymia leads to a better understanding of how alexithymia impacts the perception of hedonic stimuli coming from different sensory modalities. Our results imply that treatment goals for alexithymia should be the enhancement of the conscious perception of odors, supporting the use of mindfulness-based protocols in the alexithymia treatment.