Respuesta fisiológica a imágenes emocionales y déficit de congnición social en pacientes con daño cerebral en hemisferio derecho

Résumé

Right hemisphere (RH) is involved in different processes related to social cognition, such as emotion processing. Damage in different areas of RH causes an impaired functioning in emotion processing: from emotion recognition to both emotion experience and expression. One of the main causes of brain damage nowadays is stroke, which leads to an alteration in multiple levels, including social cognition and neuropsychiatric disorders. Despite an increasing interest in social cognition deficits caused by brain damage in recent years, more research is required to increase the knowledge about its characteristics, the effects caused by brain damage, brain areas involved, the impact in different processing levels, relationships among these factors as well as other potential variables involved. The present study focused on different levels of emotion processing in individuals with right-sided brain damage by a single first-ever ischemic stroke. As such, we explored the ability to recognize emotions in others through a facial emotion recognition task, along with the physiological reactivity through the assessment of the skin conductance response, as well as self-reported emotional responses. To achieve this goal, we assessed 91 individuals, though five of them were excluded as they were affected by cognitive impairment. As such, the final sample was composed of an experimental group with 41 individuals with a single RH ischemic stroke, and a control group with 45 subjects with no brain damage. Results showed an impairment in facial emotion recognition in those individuals with right-sided brain damage, along with a decrease in the intensity of their self-reported responses to social stimuli. Additionally, men presented with a more intense subjective response to pleasant stimuli compared to women. Results also showed associations among the different emotional processes themselves. Specifically, those individuals with RH stroke who showed a higher subjective emotional response presented with better facial recognition, along with an increased psychophysiological response. On the other hand, individuals in the control group showing a better performance in facial recognition presented with an increased psychophysiological response along with a diminished subjective response to emotional stimuli. The number of correlations among these emotion processes was significantly higher in the control group compared to those individuals with ischemic stroke. We also found a relationship between the disability level caused by the stroke and impairments in both facial emotion recognition and self-reported emotional response to unpleasant and non-social stimuli. Finally, results showed an association between emotion processing and different brain areas. Specifically, deficits in facial recognition were related to damage in subcortical areas such as caudate nucleus; diminished psychophysiological response was related to occipital damage; and, finally, subjective emotional response showed a trend to a decreased intensity in those individuals with frontal lobe damage. In summary, ischemic stroke in RH is related to emotion processing deficits. These deficits are, in turn, related to each other, as well as to other damage characteristics such location or subsequent disability.