Spontaneous facial expression of emotions in brain-damaged patients

Spontaneous facial expression of emotion was studied in two groups of right (N = 23) and left (N = 39) brain-damaged patients and in a control group of normal subjects (N = 28). To elicit emotions four short movies, constructed to produce positive, negative or neutral emotional responses, were used. The method used to assess the facial expression of emotions was the Facial Action Coding System. Brain-damaged patients showed less facial responses to emotional stimuli than normal controls, but no difference was observed between subjects with right and left-sided lesions either with global or disaggregated data analyses, inconsistent with the hypothesis of a specialization of the right hemisphere for facial emotional expressions. An unexpected difference was observed in response to the unpleasant movie. Both normal controls and left brain-damaged patients often averted their gaze from the screen when unpleasant material was displayed, whereas right brain-damaged patients rarely showed gaze aversion. This finding suggests that the degree of emotional involvement or manner of coping with stressful input may be reduced as a result of right brain damage.     

Disorders of autonomic responses to emotional stimuli in patients with unilateral hemispherical lesions

The authors have studied in 31 patients affected by right (N = 12) or left (N = 19) hemispheric lesions and in 10 normal controls the autonomous response to emotional stimuli. Stimuli consisted of 3 short films, aiming to provoke respectively a negative emotional reaction, a positive emotional response or a non-emotional reaction. Galvanic skin response and heart rate were considered as the dependent variables of our research. Both normal controls and left brain-damaged patients were very influenced by the emotional nature of the stimuli and showed clear signs of activation of the sympathetic and para-sympathetic systems in front of emotional films. By contrast, right brain-damaged patients were not influenced by the emotional or non-emotional nature of the stimuli and showed neither a clear galvanic skin response nor a significant decrease of heart rate in front of emotional films.     

Posed emotional expression in unilateral brain damaged patients

The facial expressions of six basic emotions were posed by two groups of right (N = 23) and left (N = 34) brain damaged patients and by a control group of normal subjects (N = 28). The posed expressions were examined by means of the Facial Action Coding System (FACS) which provides analytical and objective scoring, as by a subjective scale of appropriateness of expression. Results indicated no difference between controls and patients with a lesion in the right or left hemisphere. These findings are inconsistent with the hypothesis that the right hemisphere plays a specific role in the control of posed facial expression. No relationship was observed between posed emotional expressions and facial paralysis or the presence of oral apraxia.     

Specific impairments in the recognition of emotional facial expressions in Parkinson's disease

Studies investigating the ability to recognize emotional facial expressions in non-demented individuals with Parkinson's disease (PD) have yielded equivocal findings. A possible reason for this variability may lie in the confounding of emotion recognition with cognitive task requirements, a confound arising from the lack of a control condition using non-emotional stimuli. The present study examined emotional facial expression recognition abilities in 20 non-demented patients with PD and 23 control participants relative to their performance on a non-emotional landscape categorization test with comparable task requirements. We found that PD participants were normal on the control task but exhibited selective impairments in the recognition of facial emotion, specifically for anger (driven by those with right hemisphere pathology) and surprise (driven by those with left hemisphere pathology), even when controlling for depression level. Male but not female PD participants further displayed specific deficits in the recognition of fearful expressions. We suggest that the neural substrates that may subserve these impairments include the ventral striatum, amygdala, and prefrontal cortices. Finally, we observed that in PD participants, deficiencies in facial emotion recognition correlated with higher levels of interpersonal distress, which calls attention to the significant psychosocial impact that facial emotion recognition impairments may have on individuals with PD.     

The expression and perception of facial emotion in brain-damaged patients

This study examined the expression and perception of facial emotion in patients with unilateral cerebrovascular pathology. Subjects were 12 right brain-damaged (RBD), 15 left brain-damaged (LBD) aphasic, and 16 normal control (NC) right-handed males. Expressions were elicited during posed and spontaneous conditions. Both positive and negative emotions were studied. RBDs were significantly impaired, relative to LBDs and NCs, in expressing and perceiving facial emotion. There were no group differences as a function of condition, but there were differences as a function of emotional valence. Qualitative performance differences also were observed. There was no evidence that the ability to produce a particular emotion was related to the ability to identify the same emotion. Overall, these findings support the notion that the right cerebral hemisphere is dominant for expressing and perceiving facial emotion.     

Reactions of patients with focal cerebral lesions to success or failure

Multiple measures were used to investigate emotional reactions to card sorting in patients with focal cerebral lesions and in matched non-brain-injured controls. Spontaneous facial expressions of patients with anterior lesions were impoverished, relative to the posterior group, on a quantitative index of facial movement. This deficit did not appear to be attributable to group differences on lesion variables, or degree of cognitive deficit. There were also indications that a "non-emotional" facial-motor deficit was not the primary cause. The marked anterior deficit for facial movement was not, however, associated with equally pronounced deficits on qualitative, self-report and heart rate indices of emotional response. Right hemisphere patients differed from left hemisphere patients on only one qualitative measure of emotional reaction, but this may have been due to the stronger negative reactions of dysphasic patients. Left unilateral neglect was not associated with reduced emotional response.     

A preliminary characterization of lexical emotional expression in right and left brain-damaged patients

Disorders in nonverbal communication of emotion have been documented in patients with right hemisphere pathology; lexical expression of emotion is virtually unstudied. In this preliminary investigation, emotionally laden slides were used to elicit discourse from right brain-damaged (RBD), left brain-damaged (LBD), and normal control (NC) subjects. New techniques were developed to examine the ability of these subjects to express emotion in words; formalistic and pragmatic analyses of the discourse were conducted. RBDs, relative to NCs and LBDs, were less successful in using words to convey emotion and produced words of lower emotional intensity. LBD aphasics, despite their linguistic deficits, were comparable to NCs in conveying emotional valence. The data tend to support the speculation that the right hemisphere is dominant for lexical expression of emotion. This study has implications for the neuropsychological investigation of language, emotion, and the brain.     

Nonverbal Communication of Affect in Brain-Damaged Patients

A slide viewing technique designed to assess spontaneous nonverbal expressiveness was administered to 37 male patients including 8 left hemisphere damaged (aphasic), 10 right hemisphere damaged, 9 Parkinson's disease, 10 non brain-damaged (control) patients. Patients watched different types of affective slides while there facial/gestural responses were videotaped. Judges watching the video tapes without audio guessed the types of slide being viewed. Results indicated that aphasic patients were equal to or more expressive than controls, while right hemisphere damaged and Parkinson's disease patients were less expressive. The possibility that spontaneous non verbal expressiveness is mediated by the right cerebral hemisphere, with the left hemispere playing an inhibitory role, was discussed as a tentative explanation.     

Brain dysfunctions during facial discrimination in schizophrenia: Selective association to affect decoding

Schizophrenia patients exhibit impaired facial affect perception, yet the exact nature of this impairment remains unclear. We investigated neural activity related to processing facial emotional and non-emotional information and complex images in 12 schizophrenia patients and 15 healthy controls using functional magnetic resonance imaging. All subjects performed a facial information processing task with three conditions: matching facial emotion, matching facial identity, and matching complex visual patterns. Patients and controls showed comparable behavioral performance in all task conditions. The neural activation patterns in schizophrenia patients and healthy controls were distinctly different while processing affect-related facial information but not other non-emotional facial features. During emotion matching, orbital frontal cortex and left amydala activations were found in controls but not in patients. When comparing emotion versus identity matching, controls activated the fusiform and middle temporal gyri, left superior temporal gyrus, and right inferior and middle frontal gyrus, whereas schizophrenia patients only activated the middle and inferior frontal gyri, the frontal operculi and the right insular cortex. Our findings suggest that schizophrenia patients and healthy controls may utilize different neural networks when processing facial emotional information.     

Posed facial emotional expression in brain-damaged patients

Posed emotional facial expression was examined in brain-damaged adults with right (RBD) or left (LBD) hemisphere cerebrovascular lesions and in matched normal controls (NC). Subjects were videotaped while posing eight facial expressions (positive and negative) under two elicitation conditions (verbal command and visual imitation). Expressions were rated by four na?ve judges for intensity, category accuracy, and valence accuracy. RBDs were significantly more impaired than LBDs or NCs on category and valence accuracy, while LBDs posed expressions with significantly more intensity than RBDs or NCs. These findings held for positive emotions only. The results for category accuracy replicate an earlier report (Borod et al., 1986) which utilized a different rating procedure. Finally, expressions posed to visual imitation were rated as more intense and more accurate than those posed to verbal command.     

Perception of emotions from faces and voices following unilateral brain damage

The importance of the right hemisphere in emotion perception in general has been well documented but its precise role is disputed. We compared the performance of 30 right hemisphere damaged (RHD) patients, 30 left hemisphere damaged (LHD) patients, and 50 healthy controls on both facial and vocal affect perception tasks of specific emotions. Brain damaged subjects had a single episode cerebrovascular accident localised to one hemisphere. The results showed that right hemisphere patients were markedly impaired relative to left hemisphere and healthy controls on test performance: labelling and recognition of facial expressions and recognition of emotions conveyed by prosody. This pertained at the level of individual basic emotions, positive versus negative, and emotional expressions in general. The impairment remained highly significant despite covarying for the group's poorer accuracy on a neutral facial perception test and identification of neutral vocal expressions. The LHD group were only impaired relative to controls on facial emotion tasks when their performance was summed over all the emotion categories and before age and other cognitive factors were taken into account. However, on the prosody test the LHD patients showed significant impairment, performing mid-way between the right hemisphere patients and healthy comparison group. Recognition of positive emotional expressions was better than negative in all subjects, and was not relatively poorer in the LHD patients. Recognition of individual emotions in one modality correlated weakly with recognition in another, in all three groups. These data confirm the primacy of the right hemisphere in processing all emotional expressions across modalities--both positive and negative--but suggest that left hemisphere emotion processing is modality specific. It is possible that the left hemisphere has a particular role in the perception of emotion conveyed through meaningful speech.     

Visuo-motor control of the ipsilateral hand: evidence from right brain-damaged patients

We investigated the extent to which the right hemisphere is involved in the control of the ipsilateral hand by analysing the kinematics of right-hand prehension in right brain-damaged (RBD) patients. We required patients to grasp one of five possible objects, equally-sized and distributed over a 40 degrees wide workspace. With the purpose of investigating the right hemisphere contribution to the on-line visuo-motor control, we also assessed patients' ability to correct their movement "in-flight", in response to a sudden change of object position. Patients' performance was compared to that of aged-matched controls. A Younger group of healthy subjects, matching the population classically tested on double-step paradigms, was also evaluated to fully assess whether patients' kinematics could be partially due to normal ageing. As a further aim, the possible influence of hemispatial neglect was evaluated by comparing the performances of right brain-damaged patients with and without neglect. In normal subjects, the results confirmed and extended the notion of (a). positional tuning of grip formation, and (b). fast reactions following a change in object position. In addition, subtle effects of ageing on visuo-motor behaviour were shown by less efficient movement correction in the Elderly group. Patients executing reach-to-grasp actions into the left contralesional hemispace were selectively affected in both temporal and spatial aspects of movements. While their performances were relatively well preserved in the right hemispace, patients did not show positional tuning of grip formation, nor fast corrections of their movements when acting in the left hemispace. Interestingly, similar deficits were found irrespective of the presence of neglect. These results show that the right hemisphere contributes to the processing of visuo-motor information that is necessary for executing actions with the ipsilateral hand in the contralateral space.     

The contribution of anterior and posterior regions of the right hemisphere to the recognition of emotional faces

To investigate the contribution of posterior and anterior parts of the right hemisphere (RH) to emotional facial recognition, we studied 11 participants with anterior strokes of the right hemisphere (ASRH), 16 patients with posterior strokes of the right hemisphere (PSRH), and 31 normal controls. All individuals were right-handed and nondemented. The ability to recognize emotional facial expressions was assessed by using Ekman and Friesen's (1976) Pictures of Facial Affect. Analysis revealed that both groups of patients presented with an impaired recognition of emotional faces. However, patients with PSRH were able to identify facial expressions better than participants with ASRH. In comparison to participants sustaining PSRH, patients with ASRH were particularly impaired on recognizing faces of negative valence. Thus, our results suggest that anterior parts of the RH seem to play an important role in the recognition of emotional facial expressions.     

Perception of chimeric faces in schizophrenia and right hemispheric dysfunction

The aim of this study was the assessment of cerebral specialisation in perception of emotional chimeric drawings in 50 non-chronic schizophrenics (S), 50 chronic schizophrenics (CS), 30 right brain-damaged inpatients (P), and 50 normal controls. All were marked right handers. The assessment was performed after a four-week treatment. Structure and intensity of schizophrenia symptomatology were scored on the PANSS scale. Happy-sad chimeric face drawings (David 1989) were viewed twice in free vision. A perceiver bias towards left hemiface of chimeric drawings (LHF bias) and sad bias were scored in all subjects. Subjects rated their mood at the time of testing on a visual analogue scale. The schizophrenics and right brain-damaged inpatients showed significantly weaker LHF bias compared with healthy subjects, which may suggest right cerebral hemisphere dysfunction in perception of emotional chimeric drawings. Moreover, chronic schizophrenic patients revealed significantly weaker LHF bias and sad bias compared to non-chronic subjects. There was no correlation of left perceptual bias with clinical ratings: PANSS scale, MMSE, number of hospitalisations, neuroleptic dose, and current mood, which suggests stable properties of the perceptual deficit.     

Hemispheric control of the initial and corrective components of aiming movements

This study examined whether the left and right hemispheres play differential roles in controlling the initial and corrective components of aiming movements. A simple aiming task was administered to 31 normal control subjects and 29 unilateral stroke patients (14 with right hemisphere damage and 15 with left hemisphere damage). Movement amplitude was varied (25, 64 and 100 mm) and reaction time, movement time and accuracy were measured. Through a trajectory analysis, initial and corrective movements were separated. The stroke patients performed the task with their ipsilateral arm which was compared to the normal controls' right or left are performance. Regardless of the movement amplitude the left hemisphere group's reaction time was slower, and the execution of the initial movement component was less accurate than controls. No performance deficits were found on corrective movements. Performance was not impaired for the right hemisphere group on any measures. These results are discussed in terms of the hemispheres' possible roles in controlling movements which are largely open or closed loop.     

Emotional behavior in schizophrenia and one-sided brain damage. Cerebral hemispheric asymmetry. Part I

Although, emotions play a crucial role in schizophrenia, the changes in emotional dimension in relation to brain asymmetry still remain controversial. The aim of our work was: 1) to compare the emotional behaviour between the examined groups: S--non-chronic schizophrenic patients (n = 50), CS--chronic schizophrenic patients (n = 50), N--healthy controls (n = 50), R--right brain-damaged patients (n = 30), and L--left brain-damaged patients (n = 30), 2) to assess the changes in attitude processes and in types of emotional reactions, its relation to lateralised hemisphere damage and chronicity of the schizophrenic process. All psychiatric subjects were diagnosed as paranoid schizophrenics according to DSM-IV criteria and were scored on the PANSS scale after four weeks of neuroleptic treatment. Brain-damaged patients were included if they experienced single-episode cerebrovascular accidents causing right or left hemisphere damage (confirmed in CT scan reports). The neurological patients were examined at least 3 weeks after the onset of the episode. Emotional behaviour was assessed using Observational Scale of Emotional Behaviour aimed at the evaluation of: A) attitude processes B) the emotional reactions. Our results revealed differentiated type of emotional behaviour in the examined population. Right brain-damaged patients significantly often revealed elevated mood, lack of adequacy of self-evaluation and active or negative attitude towards the environment. Left brain-damaged patients showed depressed mood, resignation, positive or seldom passive attitude to others and adequate self-evaluation. Schizophrenic patients mostly revealed indifferent mood and passive attitude to environment, their self-evaluation was rather adequate. Based on our data, the changes in emotional behaviour in schizophrenic patients might reflect frontal lobes dysfunction rather than dysfunction localised in one of cerebral hemispheres.     

Cerebral hemispheric differences in memory of emotional and non-emotional words in normal individuals

The present study was designed to examine the cerebral hemispheric differences in memory of positive, negative and non-emotional words using a new method of successive presentation to each visual half-field in which perception of each item was nearly perfect thereby allowing laterality differences for effects of emotion on memory to emerge unconfounded by perception (Experiment 1). This procedure was compared with traditional perceptual identification (Experiment 2). In Experiment 1, 12 words were presented successively in each half field in each trial followed by free recall at the end of the trial. The results showed that recall of positive and negative emotional words was better than that of non-emotional words in both visual fields. Recall of positive and negative emotional words was not different in left and right visual fields (RVFs) although the recall of non-emotional words was better in the RVF than in the left visual field (LVF). The differences in recall between emotional and non-emotional words was greater in the LVF than in the RVF. Experiment 2 used the more traditional method of perceptual identification following each visual half-field presentation of a single item. Perceptual identification was better in the RVF than the LVF in each word condition. There were no visual field differences in perceptual identification between emotional and non-emotional words, as there was for memory in Experiment 1. The results supported the hypothesis that explicit memory for emotional words was dependent more on the right hemisphere, whereas perception of both emotional and non-emotional words was more dependent on the left hemisphere.     

asymmetry of Facial Expression Related to Handedness,Footedness, and Eyedness: a Quantitative Study

This study investigates the relationship between traditional measures of lateral dominance and facial asymmetry or facedness, i.e., the relative intensity of expression "and muscular involvement" on the two sides of the face. Subjects were 19 left handed and 29 right-handed normal adults coached to produce eight facial expressions of emotion and one expression involving unilateral facial movement. Videotapes of each subject were reliably rated for facedness. a lateral dominance battery yielded preference scores for hand, foot, and eye, and performance scores for accuracy, speed, and strength. Facedness and lateral dominance scores were intercorrelated. For all subjects, facedness for the eight emotional expressions was positively related to eyedness, but unrelated to handedness or footedness. Facial asymmetry furing emotional expression was more intense on the left side of the lower , face and may be a right hemisphere function, regardless of handedness. The one expression requiring deliberate unilateral facial movement was significantly and inversely related to handedness and footedness.     

Slowing Down Presentation of Facial Movements and Vocal Sounds Enhances Facial Expression Recognition and Induces Facial–Vocal Imitation in Children with Autism

This study examined the effects of slowing down presentation of facial expressions and their corresponding vocal sounds on facial expression recognition and facial and/or vocal imitation in children with autism. Twelve autistic children and twenty-four normal control children were presented with emotional and non-emotional facial expressions on CD-Rom, under audio or silent conditions, and under dynamic visual conditions (slowly, very slowly, at normal speed) plus a static control. Overall, children with autism showed lower performance in expression recognition and more induced facial-vocal imitation than controls. In the autistic group, facial expression recognition and induced facial-vocal imitation were significantly enhanced in slow conditions. Findings may give new perspectives for understanding and intervention for verbal and emotional perceptive and communicative impairments in autistic populations.