1. * Facial thermal response to emotional stimulation
in alexithymic and non alexithymic participants
Martínez-Velázquez1 E. S., De Zorzi2 L., Antoine2 P., Nandrino2 J.-L.,
Sequeira2 H. and Honoré2 J.
1 Meritorious Autonomous University of Puebla, Mexico.
2 SCALab, CNRS UMR 9193, University of Lille, France.
Project supported by research funds of Conacyt (#237614)
Introduction
Alexithymic subjects usually manifest difficulties to identify emotional experiences and to establish interpersonal relationships. The face, which is a crucial vehicle for emotional expression, can be explored with the functional infrared thermal imaging (fITI).
Indeed, this recent non-invasive tool appears relevant to measure blood-flow related changes of facial skin temperature, which are under the control of the autonomic nervous system, an important peripheral output of emotional activation.
The aim of this study was to explore the facial thermal responses (FTRs) induced by emotional and social stimulations in non alexithymic (NA) and alexithymic (A) participants.
Material and method
Participants: Two groups were differentiated on the basis of the Toronto Alexithymia Scale (TAS; Taylor et al., 1997): non-alexithymic (NA, n=14, 24.2 ± 5.2 years old, 4 men, 10 women) and alexithymic (A, n=14, 21.0 ± 2.0 years old, 7 men, 7 women).
Stimulus: FTRs to 120 standardized pictures (IAPS, International Affective Pictures System) were recorded. These pictures were characterized in 2 bocks, with or without social relevance (i.e., containing or not human elements) and in emotional condition (unpleasant, neutral or pleasant); see the figure 1.
All the participants evaluated the valence and the arousal of pictures and responded to scales of empathy and social phobia, and the questionnaires of depression, and anxiety.
Analysis
T de student was applied to scales, questionnaires, valence and arousal scores. Average of amplitude of temperature were submitted to separate repeated-measures ANOVAs, with the blocks and emotional conditions as factors.
Procedure
Application of scales and questionnaires (20min)
Neutral
20 pictures
X 4s (2min)
Pleasant
20 pictures
X 4s (2min)
Unpleasant
20 pictures
X 4s (2min)
Block 1
With social
relevance
Black
screen
2min
Black
screen
2min
Black
screen
2min
Block 2
Without S.
relevance
Neutral
20 pictures
X 4s (2min)
Pleasant
20 pictures
X 4s (2min)
Black
screen
2min
Black
screen
2min
Unpleasant
20 pictures
X 4s (2min)
Black
screen
2min
Subjective evaluation of valance and arousal
Figure 1. The blocks and emotional conditions were counterbalanced.
Results
Temperature (amplitude)
Compared to the NA group the A participants showed:
-lower scores in the personal taking subscale of the empathy questionnaire (t23 = 2.940, p= 0.00) and higher scores to social phobia (t25 = , p= 0.02).
Positive correlation between trait-anxiety score and pleasant (r = .637 p = 0.01) and unpleasant (r = .603 p = 0.02) thermal amplitude with social relevance in the NA group but not in A group (r = .135 p = 0.66).
The subjective evaluation of pictures were similar in both groups, to valence (with social t25 = -.745, p= .46; and without social relevance t25 = .091, p= .58) and arousal (with social t25 = , p= .07, and without social relevance t25 = -.552, p= .58).
FTR showed no emotional valence (F25 = 1.645, p = 27) and no social content effects (F25 = 0.98, p = .75).
The emotional activation effect, i.e. the difference between emotional and neutral conditions on FTR differed in the two groups (F25 = 3.379, p = 0.04): it was present in NA, not in A (see figure 2).
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6 * °C
Non alexithymic
Non Alexithymic
Alexithymic
Figure 2. The grapics show the amplitude average of themperature disminution and 2 standart errors to not alexithymia and alexithymia groups. PT. * = p <0.0 5
Conclusion
Alexithymic participants obtained psychometric scores indicating lower skills than NA for interpersonal relationships. This group also presented a social phobia co-morbidity. A relation between trait anxiety and temperature diminution same associated with emotional stimulation but only in non alexithymia subjects, however it is necessary to confirmer this evidence in future studies.
Interestingly, while the classical emotional activation effect was confirmed on FTRs of the non-alexithymic group, it was absent in the alexithymic participants.
These data suggest that the FTR have the potentiality to disentangle emotional from non-emotional information. The difficulty of alexithymic persons to deal with emotional information is confirmed by this new psychophysiological autonomic marker.
Reference: Taylor, G. J., Bagby, R. M., & Parker, J.D.A.(1997). Disorders of affect regulation: Alexithymia in medical and psychiatric llness. Cambridge University Press.
Dr. Eduardo Salvador Martínez-Velázquez
Prof. Henrique Sequeira