Biomedical subjects

M K Mandal

Publications and source records attributed to M K Mandal.

At least 19 recordsLinked to original sources

PubMed2004

Hand preference in patients with allergy, juvenile cancer, and schizophrenia.

Patients with allergy (n = 50), juvenile cancer (n = 50), and schizophrenia (n = 37), and nonpatient controls (n = 200) were asked to indicate their hand preferences on a 7-point scale (1 = left always, 7 = right always) for the 32-item Waterloo Handedness Questionnaire. Except for patients with schizophrenia, who exhibited a higher incidence of mixed hand preference, groups showed a clear rightward bias. Further analyses suggested that mixed hand preference in schizophrenia was evident more often for unskilled than skilled hand activities.

Adolescent↗

PubMed2001

Transfer and interference of motor skills in people with intellectual disability.

Atypical laterality (i.e. the lack of a clear pattern of lateralization) has been found to be a characteristic feature of individuals with intellectual disability (ID). The evidence for this has been based on 'handedness' studies which have contained little information about the ability of people with ID to carry out interhemispheric tasks reflecting bilateral transfer or interference. The present study examined this capacity in individuals with ID by utilizing bilateral transfer and interference paradigms. Right-handed subjects with ID (IQ = 55-76) and controls matched for age and sex were tested for bilateral transfer of motor skill in contralateral hands with a mirror-drawing task. The subjects were also tested for their ability to perform a finger-tapping task while processing verbal and non-verbal stimuli. The findings indicated that people with ID are significantly deficient relative to matched controls in bilateral transfer of motor skills from their non-preferred (left) hand to their preferred (right) one. The effect of interference during performance of the dual task was significantly greater in individuals with ID. Subjects with ID were found to perform better with their non-preferred than with their preferred hand. A within-group comparison revealed that right-handed performance was more affected by interference than left in these subjects.

Adolescent↗

PubMed2001

Visual-field bias in the judgment of facial expression of emotion.

The left and right hemispheres of the brain are differentially related to the processing of emotions. Although there is little doubt that the right hemisphere is relatively superior for processing negative emotions, controversy exists over the hemispheric role in the processing of positive emotions. Eighty right-handed normal male participants were examined for visual-field (left-right) differences in the perception of facial expressions of emotion. Facial composite (RR, LL) and hemifacial (R, L) sets depicting emotion expressions of happiness and sadness were prepared. Pairs of such photographs were presented bilaterally for 150 ms, and participants were asked to select the photographs that looked more expressive. A left visual-field superiority (a right-hemisphere function) was found for sad facial emotion. A hemispheric advantage in the perception of happy expression was not found.

Adolescent↗

PubMed2001

Cultural variation in hemifacial asymmetry of emotion expressions.

Photographs of hemifacial composites (left-left, right-right and normal presentation, right-left) of these cultures (Japanese, Oriental Indian and North American) displaying six emotions (happy, sad, fear, anger, surprise, disgust) and a neutral state were administered successively (one by one) as well as simultaneously (three hemifacial photographs of an expression at a time) to observers for judgment on a 5-point scale in terms of distinctiveness of expression. Observers' judgments were treated with a culture of expressor x sex of expressor x facial presentation x emotion category mixed factorial ANOVA. Cultures did not vary for their distinctiveness of facial expressions, suggesting universality in this respect. Culture-specificity was, however, observed with respect to hemifacial asymmetry and valence of emotion expressions: (1) Japanese showed a right hemifacial bias for positive and left hemifacial bias for negative emotions; Indians and North Americans showed left hemifacial bias for all emotions, and (2) negative emotion expressions were least distinctly identifiable in Japanese faces followed by Indian and North American faces.

Adolescent↗

PubMed2001

Side bias and accidents: are they related?

This study purports to examine the role of different forms of side bias, handedness, footedness, eyedness, and earedness, in eliciting accident-proneness in individuals. A representative sample (N = 150) was administered a Side Bias Questionnaire (Handedness: 22 items, footedness: 5 items, eyedness: 5 items, earedness: 5 items) to ascertain their preferential bias. The questionnaire also required subjects to report the number of accidents committed during their lifetime while performing activities like sports, driving, household work, etc., that required attention of medical professionals. Regression analysis of data indicated that accident-prone behavior was significantly predicted from handedness. Analysis of variance, 3 (Accident groups: low, moderate, high) x 4 (Side bias: hand, foot, eye, ear), indicated that 'mixed' handers committed more accidents as compared with clear handers. The other forms of side bias, foot, ear, and eye were unrelated to frequency of accidents.

Accidents, Traffic↗

PubMed2001

Side bias and accidents in Japan and India.

The purpose of this study was to examine (a) the incidence of leftward bias for paired organs (hand, foot, eye, and ear) in India (n = 418) and Japan (n = 697), and (b) the incidence of accident amongst individuals with leftward, rightward, and no bias across countries. The impetus for the study was obtained from a speculation that individuals with leftward bias commit more accidents than their counterparts. Data were collected with the help of a questionnaire on side bias, along with a check-list on accidents (included in the questionnaire). Results showed that participants from these two countries did not differ in terms of leftwardness for any of these forms of side bias. Left-handers were found to commit more accidents in India but not in Japan. Reanalysis of data in terms of left-, mixed-, and right-handedness indicated that mixed handers committed more accidents than extreme (left- + right-) handers in Japan but not in India.

Accidents↗

PubMed2000

Emotional processing in schizophrenia across cultures: standardized measures of discrimination and experience.

Schizophrenia appears quite similar across a range of cultures. However, variability has been noted, and understanding the variant and invariant features of the disorder is necessary for elucidating its biological and environmental basis. Evidence of prominent emotion processing deficits in schizophrenia, including perceptual and experiential aspects, led us to extend the paradigm of standardized measures cross-culturally. We assessed performance of American, German, and Indian patients with schizophrenia and healthy controls on standardized emotion discrimination and experience (mood induction) procedures using happy, sad, and neutral facial expressions of Caucasian actors. Participants were 80 Americans (40 patients; 40 controls), 48 Germans (24 patients; 24 controls), and 58 Indians (29 patients; 29 controls). Face discrimination performance was impaired across patient groups, but was most impaired in those of Indian origin. Lower performance was also found in Indian controls, relative to their American and German counterparts. Mood induction produced weaker effects in all patient groups relative to their respective controls. The results supported the feasibility of cross-cultural comparisons and also emphasized the importance of poser ethnic background for facial affect identification, while poser ethnicity was less consequential for mood induction effects. Emotion processing deficits in schizophrenia may add to the clinical burden, and merit further examination.

Adult↗

PubMed2000

Performance on a mirror-drawing task by non-right-handers.

Left-, mixed-, and right-handed (each n = 10, N = 30) adolescent boys who were classified on the basis of a hand preference inventory performed a mirror-drawing task with a bilateral transfer of a skill paradigm. Participants' hand preference and the magnitude of bilateral transfer of skill were assessed in terms of errors committed and time taken to complete the mirror-drawing task. Mixed-handed participants exhibited significantly less habit interference for mirror drawing, and they performed the task significantly faster than the left-handers did; the group difference was not significant for the frequency of errors committed. These groups did not differ in terms of the magnitude of bilateral transfer of skill; the trend, however, showed that the transfer of skill was minimum in mixed-handers. These findings extend the theory that mixed-handed participants' inability to transfer motor skill from one hand to the other could be attributable to their lack of a clear pattern of lateralization. Their ability to perform well either at initial or later trials may be a function of less interference from their normal motor habits.

Adolescent↗

PubMed2000

Somatoperceptual asymmetry for cognitive stimuli: support from experimental and clinical observations.

Two studies, one experimental with intact-brain subjects (Study I), and one clinical with left or right hemisphere-damaged and non-neurological general medical patients (Study II), were conducted to examine somatolateral asymmetry in the recognition of verbal (letter) and visuospatial (nonsense shapes) stimuli. Blindfolded subjects were required to explore two stimuli dichhaptically, and were instructed to haptically identify the target stimulus in a set of test stimuli. The findings of Study I indicated that fewer trials were required to recognise nonsense shapes when they were presented to the left hand, whereas fewer trials were required for letters when they were presented to the right hand. The findings of Study II indicated that performance of the hand ipsilateral to the damaged left hemisphere was better for nonsense shapes than for letters, and performance of the hand ipsilateral to the damaged right hemisphere was better for letters than for nonsense shapes.

Journal Article↗

PubMed2000

Tactual recognition of cognitive stimuli: roles of hemisphere and lobe.

Four groups of focal brain-damaged patients, involving left and right hemisphere damage with or without the involvement of parietal lobe, and a control group of general medical patients, were required (a) dichaptically to perceive two cognitive stimuli (letter letter, figure figure, or letter figure), and (b) haptically match the target stimulus from a set of test stimuli. The number of trials taken to match the target stimulus correctly was the dependent measure. The significant main effect of lobe suggested that the parietal lobe is the primary locus for tactual recognition. All interaction effects involving lobe were nonsignificant. The main effect of hemisphere was nonsignificant, although the interaction of hemisphere x lobe was significant. Left and right hemisphere damaged patients required more trials to recognize "letter" and "figure", respectively.

Adult↗

PubMed1999

Generality and specificity of emotion-recognition deficit in schizophrenic patients with positive and negative symptoms.

Schizophrenic patients with positive and negative symptoms, as well as non-patient control subjects, were asked to recognize emotional stimuli of happy, sad, and neutral facial expressions. Dependent measures were the percentage of correct responses, and the incorrect use of an emotion category owing to false recognition. Schizophrenic patients with negative symptoms exhibited a generalized emotion-recognition deficit, and their use of emotion categories during false recognition was random. Schizophrenic patients with positive symptoms showed a deficit in their recognition of 'sad' emotion and were 'positively biased' to the category 'happy' as reflected by its most frequent usage during false recognition.

Adult↗

PubMed1999

Pattern of social interaction in societies of the Asia-Pacific region.

The authors developed an 18-item Social Interaction Inventory that yielded a factorial structure based on the 3 domains of social interaction: interpersonal, personal, and extrapersonal. They administered the inventory to samples from 15 countries of the Asia-Pacific region (N = 146). The participants in the different cultural groups preferred to interact more within the interpersonal (in-group) domain as compared with the personal (individual) and extrapersonal (out-group) domains. The findings reflect a collective pattern, rather than an individualistic pattern, of social interaction in the societies of the Asia-Pacific region.

Adult↗

PubMed1999

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.

Analysis of Variance↗

PubMed1998

Visuospatial and affect recognition deficit in depression.

BACKGROUND: Theorists differ in their opinion whether interpersonal difficulties in depression is associated more with perceptual impairment or with emotional bias. The present study intended to resolve such differences of opinion. METHOD: Major depressives, general medical patients, and non-patient controls were administered three visuospatial and two affective tasks to examine the nature of performance deficit associated with each group. RESULTS: Major depressives were found significantly impaired in both visuospatial and affective tasks in comparison to general medical patients, who in turn, were impaired than non-patient controls. CONCLUSION: Major depressives' perceptual deficit is pervasive and not specific to affective categories. LIMITATION: The study could have been more informative if more psychiatric groups had been included as subjects. CLINICAL RELEVANCE: Improvement in depressives' ability for visuospatial and affective tasks may be considered as a marker of their clinical improvement.

Adult↗

PubMed1998

Side bias in schizophrenia: hand, foot, eye, and ear.

Schizophrenics and normal controls were examined for their side (lateral) bias in terms of hand, foot, eye, and ear. Preference and performance measures were taken. The findings indicated a rightward bias for both measures in controls and in participants with schizophrenia. Side pattern was congruent between those with and without schizophrenia, with limb lateralization (hand, foot) orthogonal to sense-organ lateralization (eye, ear). Analysis of right- and left-side responses indicated a significant group difference for eye bias and ear bias as a function of response measures, preference, and performance.

Adult↗

PubMed1998

Handedness in mental retardation.

Mentally retarded and age-matched normal controls with no history of parental sinistrality were examined for their handedness with the Waterloo Handedness Questionnaire (Singh & Bryden, 1994). Normal controls showed a clear rightward bias, with the effect being significantly higher for skilled as compared to unskilled hand items. Mentally retarded subjects showed mixed handedness with a nonsignificant difference in performance between skilled and unskilled hand items.

Journal Article↗

PubMed1998

Facial expressions of emotions and schizophrenia: a review.

It is generally agreed that schizophrenia patients show a markedly reduced ability to perceive and express facial emotions. Previous studies have shown, however, that such deficits are emotion-specific in schizophrenia and not generalized. Three kinds of studies were examined: decoding studies dealing with schizophrenia patients' ability to perceive universally recognized facial expressions of emotions, encoding studies dealing with schizophrenia patients' ability to express certain facial emotions, and studies of subjective reactions of patients' sensitivity toward universally recognized facial expressions of emotions. A review of these studies shows that schizophrenia patients, despite a general impairment of perception or expression of facial emotions, are highly sensitive to certain negative emotions of fear and anger. These observations are discussed in the light of hemispheric theory, which accounts for a generalized performance deficit, and social-cognitive theory, which accounts for an emotion-specific deficit in schizophrenia.

Emotions↗

PubMed1998

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 right hemisphere damaged patients in matching photographs of emotion expressions that were depicted in line drawings of normal face and schematic face.

Adult↗