Left hemisphere dysfunction and left hemisphere overactivation in schizophrenia.

Reports 2 experiments relating schizophrenia to functional brain asymmetry. In Exp I, 24 schizophrenics (mean age, 30.8 yrs) were compared to 24 matched controls (mean age, 37.3 yrs) on 2 tachistoscopic tasks (Syllable Test and Dot Location Test) designed to measure verbal and spatial information processing in the 2 hemispheres. Unlike the controls, the schizophrenics showed a right hemisphere superiority both on the verbal and on the spatial tests, indicating left hemisphere dysfunction in the initial processing of verbal information. In Exp II, lateral eye movements, as an index of contralateral hemispheric activation, were measured in a group of 24 paranoid schizophrenics (mean age, 28.9 yrs), 24 nonparanoid schizophrenics (mean age, 32.7 yrs), and 24 matched controls (mean age, 31.2 yrs). The eye movements were elicited by presenting the Ss with verbal neutral, verbal emotional, spatial neutral, and spatial emotional questions. The schizophrenics had significantly more rightward eye movement, compared to controls, regardless of question type, indicating left hemisphere overactivation. Results suggest that schizophrenia is associated with a pattern consisting of both left hemisphere dysfunction and overactivation. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonstandard neuropsychological assessment: An illustration.

Administered 2 versions of the Progressive Matrices to 35 patients with unilateral stroke. 12 Ss (mean age 60.9 yrs) had left hemisphere damage, and 23 Ss (mean age 59.6 yrs) had right hemisphere damage. Half of the items were given in standard form; the remaining items were physically rearranged so that the 6 response alternatives were aligned in a single column, eliminating the need for lateral scanning. Ss with unilateral neglect achieved significantly higher scores when the format was modified to minimize the need for lateral scanning. Ss without neglect were largely unaffected by differences in format. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age- and sex-related differences in left- and right-hemisphere processing by learning disabled children.

Age and sex differences in left- and right-hemisphere processing were assessed with 2 dichotic listening tasks in a sample of 48 control and 48 learning-disabled (LD) children ranging in age from 6 yrs 9 mo to 12 yrs 4 mo. Children were presented with consonant–vowel syllables (CVs) and simple square-wave and complex square-wave tones. Neither age nor sex differences in response accuracy or lateralized processing of CV stimuli were evident for control children. Borderline significance was obtained for tonal stimuli. In contrast, CV stimuli elicited a bilateral response in younger LD children, and tonal stimuli elicited a bilateral response in all LD children. Furthermore, control children were oppositely lateralized for verbal and nonverbal stimuli, whereas LD Ss exhibited a general processing bias to the same hemisphere. These data support the theory that LD children may lack the necessary functional specialization required for lateralized processing of such stimuli. In addition, these data do not fully support the developmental invariance hypothesis and may even suggest a putative right-hemisphere or bilateral processing deficiency in LD children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric asymmetry in Down's Syndrome children.

Examined auditory processing of linguistic stimulation presented dichotically to groups of 30 Down's Syndrome (DS) children, 20 non-DS retarded children who were MA and CA matched, and 20 MA matched nonretarded children, all of whom were right-handed. Ss completed a knowledge-of-numbers test and the Slosson Intelligence Test. They then listened to 20 trials of a dichotic message at approximately 70–75 db and repeated digits they heard. DS Ss showed a significant left ear advantage in processing the auditory linguistic material, while the other Ss showed the normal right ear advantage. Findings corroborate that having DS has a specific effect on the functional organization of the CNS auditory system. The right hemisphere may not be as efficient as the left hemisphere at language processing. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Left-ear superiority in children for processing auditory emotional material.

Investigated hemispheric asymmetries in children for processing auditory material varying in emotional intonation or verbal content. 31 kindergartners, 32 4th graders, and 32 8th graders reported on the emotional content and on the verbal content of dichotically presented sentences. Ss listened to tapes of 4 phrases spoken in tones that were happy, sad, angry, or neutral and to sentences that varied in verbal content only. Ss also completed a handedness questionnaire and a hearing test. All age groups showed a left-ear advantage for reporting on the emotional material and a right-ear advantage for reporting on the verbal material. For the emotional task, the degree of ear asymmetry did not vary significantly as a function of emotional category. Findings indicate the the right hemisphere is specialized for mediating auditory emotional stimuli as early as 5 yrs of age. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in hemispheric specialization for tactile spatial ability.

64 1st-, 3rd, and 5th-grade children and adults (16 in each group) performed a tactile shape-discrimination task. On each of 40 trials, after exploring a randomly generated nonsense form using only finger motion, Ss judged a tactually presented comparison form as either the same as or different from the 1st stimulus. In Condition 1, a single stimulus form and the comparison form were successively presented to the same hand. In Condition 2, stimulus forms were simultaneously presented to both hands; however, a comparison form was presented to only one hand. Results indicate that the left hand (right hemisphere) was more accurate than the right hand (left hemisphere) for 5th-grade Ss and adults, but no significant differences between hands were found for 1st- and 3rd-grade Ss. Overall, Condition 2 was more difficult than Condition 1, but similar laterality effects were found in both groups. Sex differences were found only in the adult group in which males made somewhat fewer errors than females. These results suggest that the right hemisphere becomes progressively more specialized for tactile spatial ability with increasing age. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual laterality and iconic recognition of visual materials by Korsakoff patients and normal adults.

Compared 9 male patients with Korsakoff's syndrome to 19 normal and 11 alcoholic control Ss on their threshold for recognition of words or patterns presented monocularly to the lateral visual fields. Ss were then tested on backward visual masking of the same (target) stimuli to determine the interstimulus interval (ISI) needed to escape the masking effect (critical ISI) in each lateral field. Threshold for recognition and critical ISI were elevated in Korsakoff Ss. For all Ss, the right visual field was superior to the left for word recognition but not for pattern recognition. The critical ISIs were shorter in the right visual field for both types of material, suggesting that the dominant hemisphere is more efficient in the early (iconic) stages of information processing. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anomalous perceptual asymmetries for negative emotional stimuli in the psychopath.

This study tested the hypothesis that when processing negative emotional material, psychopaths, compared with nonpsychopaths, would rely less on connotative-emotional processes based in the right hemisphere and more on denotative-linguistic processes based in the left hemisphere. Psychopathic and nonpsychopathic inmate groups, defined by their scores on the Psychopathy Checklist—Revised (R. D. Hare 1985), completed 2 analogous tachistoscopic tasks (words and faces). Accuracy and reaction times of inmates' responses in identifying which of 2 bilaterally presented stimuli (1 neutral and 1 emotional) was the emotional stimulus were measured. Significant lateral processing differences between the 2 groups emerged on the word task but not on the face task, providing partial support for the experimental hypothesis. Psychopaths also showed lower generalized emotional responsivity than nonpsychopaths on the Affect Intensity Measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Grammatical awareness in the spoken and written language of language-disabled children.

Two experiments examined judgment, revision, and error-identification deficits in relation to expressive language skills and morphemic errors in writing. 12 language-disabled (LND) children (aged 8 yrs 2 mo to 12 yrs 4 mo) and 11 controls (aged 6 yrs 3 mo to 6 yrs 11 mo) matched for language ability participated in Exp 1. 11 LND children (aged 9 yrs 1 mo to 12 yrs 2 mo), 11 age-matched children with no language disability, and 11 children (aged 6 yrs 2 mo to 8 yrs 0 mo) matched to LND Ss for language ability participated in Exp 2. LND Ss who did not lack expressive use of target morphemes also did not differ from language-matched Ss in their ability to (1) judge the grammaticality of spoken sentences, (2) revise them, and (3) identify errors. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of intramodal and crossmodal stimulus diversity on the reaction time of chronic schizophrenics.

Compared 16 chronic schizophrenics (mean age 42.7 yrs), 16 alcoholic inpatients (mean age 37.6 yrs), and 16 healthy Ss (mean age 36.9 yrs) with respect to their RTs to stimuli from 1 (ipsimodal condition) or 2 (crossmodal condition) modalities. In the ipsimodal condition, a low-pitched sound presented to one ear and a high-pitched sound presented to the other ear served as imperative stimuli, alternating randomly. In the crossmodal condition, a light or a sound was presented. In responding to the sound imperative stimuli, schizophrenics were more retarded than were comparison groups when the preceding imperative stimulus was a light or a different sound, relative to when it was the same sound. With the inclusion of warning stimuli of either modality into the crossmodal condition, both comparison groups were more retarded than were schizophrenics when the preceding imperative stimulus was a light, relative to when it was the same sound. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotic hallucination alters evoked potentials.

Studied whether the amplitude of the visual EP is reduced during hypnotic hallucination in which the S is instructed to perceive visual stimuli as diminished in brightness or obstructed from view. The visual EP responses of 6 high- and 6 low-hypnotizable Ss (aged 18–33 yrs) and of 6 undergraduate controls were compared in 3 hypnotic conditions: stimulus enhancement, stimulus diminution, and stimulus elimination (obstructive hallucination). ANOVA revealed that high-hypnotizable Ss demonstrated significant suppression of the later components of the EP response (N? and P?) while experiencing obstructive hallucinations, indicating a change in information processing. This effect was significantly greater in the right, as compared to the left, occipital region. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential hemispheric processing of faces: Methodological considerations and reinterpretation.

Examines the procedures and stimuli (physiognomies) used in lateralized face recognition experiments with normal Ss, as well as in related perceptual and identification experiments. Results reveal that in general a left visual field (right hemisphere) advantage is obtained when: (a) stimulus information is degraded; (b) faces to be compared are highly discriminable; (c) set of unfamiliar faces is used; and (d) task requirements allow a lax criterion of recognition. These conditions seem to make holistic processing adequate for the task; if the conditions require analytic judgments, then a right visual field (left hemisphere) advantage may be obtained. Thus, no hemifield has an inherent or absolute advantage and these procedural conditions may critically determine what hemifield advantage is observed in any given experiment with faces (or other types of stimuli). Apparently, both hemispheres may contribute to the processing of faces but their contributions vary as a function of task demands. A right hemisphere advantage may reflect an enhanced role of the processes of configuration, completion, categorization, or set. A left hemisphere advantage need not involve the language function but it may reflect a genuine visuospatial contribution. (60 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex similarities in verbal and performance IQ deficits following unilateral cerebral lesions.

Investigated whether men and women produce similar Verbal IQ and Performance IQ patterns following unilateral cerebral lesions. Ss included 24 women (mean age 43.96 yrs) and 24 men (mean age 45.08 yrs) with independent neurological evidence of neoplastic or vascular lesions of the right cerebral hemisphere, 24 women (mean age 47.88 yrs) and 24 men (mean age 47.50 yrs) with such lesion evidence of the left cerebral hemisphere, and 14 female (mean age 46.43 yrs) and 14 male (mean age 45.50 yrs) controls. Each group was equated for education, lesion site, severity, chronicity, and etiology. Ss were administered the Wechsler-Bellevue Intelligence Scale, and differences in Verbal and Performance IQ values were compared. Contrary to reports in the literature, no consistent evidence of Sex?×?Lesioned Hemisphere interactions was found. Differences in the lateralization effects between men and women were not reflected in direction or pattern but only in magnitude, arguing against a theory of differential cognitive lateralization according to sex. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuroticism and extraversion in Turner's Syndrome.

Administered the Maudsley Personality Inventory to 5 groups of female Ss: (a) 13 Turner Syndrome Ss (mean age 19 yrs 2 mo) with karyotype 45X, (b) 18 Turner Syndrome (TS) Ss (mean age 26 yrs 11 mo) with other types of sex chromosomal abnormalities, (c) 16 sisters of Ss (mean age 24 yrs 2 mo), (d) 9 Ss with growth retardation and primary amenorrhea (mean age 22 yrs 4 mo), and (e) 19 nurses (mean age 22 yrs 8 mo). The results are compared to English and American normative values. The total group of TS Ss obtained a low Neuroticism (N) score compared to the control groups. When the total group was divided on the basis of their karyotypes, the low N score could be referred solely to Ss with karyotype 45X, who scored significantly lower than any other group tested so far with the MPI. TS Ss with chromosomal abnormalities other than 45X scored within normal limits. No variables other than karyotype 45X were related to an extremely low N score. It is concluded that exceptional emotional stability, as reflected in a very low N score on the MPI, is concomitant with the total absence of one sex chromosome, which is probably due to a developmental abnormality of the CNS. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anxiety and perceptual structure: Individual differences in neuropsychological function.

Studied the cognitive performance of 24 high and 36 low trait anxious undergraduates under conditions of high and low situational stress, using tasks requiring greater contribution of the right or left hemisphere. In addition, a perceptual task was adapted from visual information processing research to assess Ss' global or analytic approaches to perception; if anxiety increased the left hemisphere's contribution to perception, anxious Ss might be expected to be more analytic and detail oriented. Results show no significant differences on left hemisphere tasks but a significant interaction of trait by state anxiety for right hemisphere tasks: Low trait Ss performed better and high trait Ss performed more poorly under situational stress. Trait anxiety showed a significant main effect on visual information processing strategy, low Ss tending to be more global and high Ss tending to process the stimulus analytically. Results support the utility of a neuropsychological model in describing the effects of emotion on perception. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of distinctive features on recognition of incomplete pictures.

Conducted 2 experiments to determine the effects of distinctive features on recognition of incomplete pictures. Two sets of fragmented picture stimuli were designed: Set A preserved 75% and Set B preserved 25% of the distinctive features of the objects pictured. Within each set of stimuli, a complete (C), an intermediate (I), and a most incomplete (MI) representation of the objects was constructed. In Exp I, 60 Ss of 3 different age groups (3–4 and 5–6 yrs and undergraduates) were tested on the MI representations of either Set A or Set B. Results indicate significant differences in the age groups and in stimulus sets. In Exp II, 36 children (mean age 4 yrs 6 mo) were trained on either the C or the I Set A or the I Set B representations. After a day's delay, the Ss were tested on Set A or Set B MI representations of the objects and to novel representations. Results show significant differences among training conditions and in the test of the stimulus sets. The concepts of filtering and abstraction of distinctive features as discussed by F. J. Gibson (1969) are used in interpreting the results. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental rotation of facial profiles: Age-, sex-, and ability-related differences.

48 adults (mean age 28 yrs 4 mo), 48 8th graders, and 48 4th graders determined what the left–right orientations of rotated facial profiles would be were the profiles upright. There were 24 males and 24 females in each group. Ss were all administered the Raven Standard Progressive Matrices and the Picture Vocabulary and Spatial Ability subtests of the Woodcock-Johnson Psycho-Educational Battery. Results indicate that rate of mental rotation and combined rate of encoding, comparison, and response increased with age. Findings are consistent with a speed–accuracy tradeoff explanation of previous discrepancies in developmental studies of mental rotation. Female Ss' rates of mental rotation were slower on average and more variable than male Ss. Within the entire sample, there was a modest correlation between the ability test scores and both latency and error parameters derived from the rotation task. Only error rate was discriminantly related to spatial ability, however. Patterns of correlations between processing parameters and test scores differed between age groups and, within age groups, between sexes. Mental rotation showed a significant relation to spatial ability only in 4th graders. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interhemispheric interaction when both hemispheres have access to the same stimulus information.

Right-handed Ss identified consonant-vowel-consonant (CVC) nonsense syllables presented tachistoscopically. The CVC on each trial was presented to the left visual field-right hemisphere (LVF-RH), to the right visual field-left hemisphere (RVF-LH), or the same CVC was presented to both visual fields ( bilateral presentation). When recognition was incorrect, the pattern of errors was qualitatively different on LVF-RH and RVF-LH trials, suggesting that each cerebral hemisphere has its own preferred mode of processing the CVC stimuli. The qualitative pattern of errors on bilateral trials was identical to that obtained on LVF-RH trials. The bilateral results are described well by a model that assumes the mode of processing characteristic of the RH dominates on bilateral trials but is applied to both the LVF-RH and RVF-LH stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Visual Reproduction subtest: Standardization and clinical validation of a delayed recall procedure.

Provided a normative database for a delayed recall procedure using the Visual Reproduction subtest from Form I of the Wechsler Memory Scale and examined the test's clinical sensitivity in 4 groups of patients. Normative data were based on 255 neurologically normal adults (aged 18–91 yrs). Clinical groups included 103 patients with severe head trauma, left hemisphere cerebrovascular accident (CVA), right hemisphere CVA, and Alzheimer's disease (mean ages 28.85, 63.46, 64.21, and 64.85 yrs, respectively). Normative data revealed significant age-related differences, with older Ss performing lower on both immediate and delayed recall tasks. Ss in all 4 clinical groups performed significantly below age-matched controls. Visual Reproduction scores correlated positively with measures of visual-spatial ability, verbal memory, and visual memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concomitant eyeblink and heart rate classical conditioning in young, middle-aged, and elderly human subjects.

Pavlovian heart rate (HR) and eyeblink (EB) conditioning were assessed in 4 groups of Ss who differed in age: young?=?19–33 yrs, young middle-aged?=?35–48 yrs, old middle-aged?=?50–63 yrs, and old?=?66–78 yrs. A 100-msec corneal airpuff was the unconditioned stimulus/stimuli (UCS) and a 600-msec tone was the CS. A nonassociative control group received explicitly unpaired tone and airpuff presentations. All Ss were studied for 2 100-trial sessions separated by approximately 7 days. An impairment in acquisition of both the EB and HR responses occurred in the old and middle-age Ss, but all age groups showed significantly greater conditioning than did the control group. Slight increases in performance resulted from a 2nd session of training. These findings suggest and age-related impairment in a general associative process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)