Hari S. Asthana

Right Brain Damage Impairs Recognition of Negative Emotions

Patients with right or left hemisphere-damage and normal control groups were asked to judge facial emotions from photographs presented in two orientations--upright, inverted. Responses were elicited with a matching and a verbal labelling task. Normal controls were significantly superior in the judgment of facial emotions than left hemisphere-damaged patients, who in turn were significantly superior than right hemisphere-damaged patients. Negative-aroused (fear, anger) and negative-nonaroused (sadness, disgust) facial expressions were recognized with significantly greater accuracy by left hemisphere-damaged patients compared to right hemisphere-damaged patients; the group difference in performance was nonsignificant for positive (happiness, surprise) emotions.

Effects of lesion variables and emotion type on the perception of facial emotion.

The purpose of this study was to consider the effects of valence, motoric direction (i.e., approach/withdrawal), and arousal on the perception of facial emotion in patients with unilateral cortical lesions. We also examined the influence of lesion side, site, and size on emotional perception. Subjects were 30 right-hemisphere-damaged (RHD) and 30 left-hemisphere-damaged (LHD) male patients with focal lesions restricted primarily to the frontal, temporal, or parietal lobe. Patient groups were comparable on demographic and clinical neurological variables. Subjects were tested for their ability to match photographs of four facial emotional expressions: happiness, sadness, fear, and anger. Overall, RHD patients were significantly more impaired than LHD patients in perceiving facial emotion. Lesion side, but not site, was associated with motoric direction and valence dimensions. RHD patients had specific deficits relative to LHD patients in processing negative and withdrawal emotions; there were no group differences for positive/approach emotions. Lesion size was not significantly correlated with accuracy of emotional perception.

Hemifacial Asymmetry in Emotion Expressions

We examined asymmetry in posed facial expression of emotions: happy and sad. Hemifacial composite photographs, left-left and right-right, were prepared, and subjects rated these for intensity of expressed emotion. Overall, left-left composites were judged to have expressed emotions relatively more intensely than the right-right composites. The significant Sex x Emotion interaction revealed that female expressors were judged as more expressive than male expressors in expressing sad facial emotion. Sex difference in expression of happy facial emotion was not significant.

Degree of Asymmetry in Lateral Preferences: Eye, Foot, Ear

Lateral asymmetry in eye, foot, and ear preference was measured using a 15-item questionnaire administered to 442 subjects. Degree and magnitude of asymmetry were greatest for eye, followed by foot and ear. Intercorrelations of lateral preferences were all positive and significant. Two primary factors, eyedness and earedness, were established.

CEREBRAL LATERALITY IN AFFECT AND AFFECTIVE ILLNESS : A REVIEW

It is generally claimed that affect processing is a right hemisphere function. It is also claimed that right hemisphere dysfunction is characteristic of depressive illness. These claims are not accepted without controversy, and it has been found that the relationship between affect processing and affective illness in terms of intra- and interhemispheric role is not straightforward. Two types of studies were reviewed in this context: behavioral and electrophysiological. Potential confounding effects are discussed.

Bilateral transfer deficit in schizophrenia.

Right-handed chronic schizophrenics, left-handed normals, and right-handed normals were tested on a measure of bilateral transfer of motor skill in contralateral hands. Schizophrenics compared with normals showed significantly poor bilateral transfer of skill in terms of errors committed; the group difference was nonsignificant in terms of response time. Results suggested a breakdown in perceptual-motor coordination in schizophrenia.

Right Hemisphere Damage Impairs the Ability to Process Emotional Expressions of Unusual Faces

Patients with focal brain damage, right and left hemisphere damage, and nonpatient controls were asked to match photographs of emotion expressions that were depicted in unusual (line drawings, strange, and schematic) and normal (usual) representations of faces with the target emotion expressions of normal face. Nonpatient controls were significantly superior to tight hemisphere damaged patients in matching photographs of emotion expressions that wre depicted in line drawings of normal face and schematic face.

Hemifacial Display of Emotion in the Resting State

The human face at rest displays distinguishable asymmetries with some lateralization of emotion or expression. The asymmetrical nature of the resting face was examined by preparing hemifacial composites, left-left, right-right, along with normal facial orientation. The left side and right side composites were constructed by using the lateral half of one side of the face and its mirror-reversal. The left side facial composites were found to be more emotional than the right side or normal facial orientations of neutral expressions.

Hand Preference in the Deaf

Fifty seven deaf and 71 hearing children were administered a 32-item Waterloo Handedness Questionnaire. The deaf children, in comparison to hearing children, were found to be weakly right-handed in terms of their hand preference with a relatively high incidence of mixed handedness.

Matching Top-Bottom Parts of Facial Expressions by Brain­ damaged Patients

Patients with focal brain-damage, right/left hemisphere-damage (RHD/LHD) and anterior/posterior region-damage (ARD/PRD), and normal controls (NC) were asked to match photographs of top-bottom facial parts expressing different emotions, positive (happy, surprise), negative-aroused (fear, anger), negative-nonaroused (sad, disgust). The LHD patients performed significantly worse than the RHD patients, and the ARD patients were significantly worse than the PRD patients, in the perceptual-matching task with affective stimuli. NC subjects performed significantly better than any of the brain damaged sub-groups.