The question of left hemisphere dysfunction in infantile autism.

Examines the hypothesis that dysfunction in the left hemisphere accounts for some of the primary behavioral and cognitive symptoms of autism. A particular variant of this theory is that language deficits, which are assumed to be attributable to left-hemisphere dysfunction, constitute the core deficit of the syndrome. The structure of these arguments and the empirical evidence are critically reviewed. It is concluded that the left-hemisphere hypothesis is inadequate to account for many of the cardinal features of autism, that it is based to some extent on flawed reasoning and weak evidence, and that it overestimates the importance of linguistic dysfunction in autistic children. Some of the questionable assumptions of this hypothesis include the following: (1) Language is always selectively impaired in autism; and (2) language reflects left hemisphere function. Nonlanguage evidence for left-hemisphere dysfunction is reviewed. Several alternative hypotheses are proposed to explain the possible link between left-hemisphere signs and infantile autism. (115 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abstract visual-form representations in the left cerebral hemisphere.

Visual-form systems in the cerebral hemispheres were examined in 3 experiments. After learning new types of visual forms, participants rapidly classified previously unseen prototypes of the newly learned types more efficiently when the forms were presented directly to the left hemisphere (in the right visual field) than when the forms were presented directly to the right hemisphere (in the left visual field). Neither previously seen nor previously unseen distortions of the prototypes were classified more efficiently when presented directly to the left hemisphere than when presented directly to the right hemisphere. Results indicate that an abstract visual-form system operates effectively in the left hemisphere and stores information that remains relatively invariant across the specific instances of a type of form to distinguish different types. Furthermore, this system functions relatively independently of another system that operates effectively in the right hemisphere and that stores details to distinguish specific instances of a type of form. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Left and right hemisphere contributions to physiognomic and verbal discrimination.

The relative contributions of the right- and left-temporal lobes in rapid recognition of faces and letters were studied in patients with anterior right- or left-temporal lobe excisions and a matched control group. On the basis of findings in patients with unilateral and bilateral brain damage, it was hypothesized that left hemisphere damage would not change the reaction time of letters analyzed by the right hemisphere and that right hemisphere damage would not change the reaction time of faces analyzed by the left hemisphere. The hypothesis was supported for letters but not for faces. Patients in the right-temporal group, particularly those with large hippocampal removals, were slow to recognize faces in both visual fields. Two possible explanations for the findings with faces are explored: One holds that right hemisphere mechanisms are involved even when a face is presented to the left hemisphere for rapid recognition; the other holds that specialized encoding is carried out by the right hemisphere during learning, with the encoded template then being used by each hemisphere independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye-tracking dysfunction and birth-month weather in schizophrenia.

The prevalence of eye-tracking dysfunction (ETD) is significantly elevated in individuals with a diagnosis of schizophrenia and in their nonschizophrenic relatives, suggesting that ETD marks a familial (most likely genetic) risk factor for schizophrenia. Birth in a season with intemperate weather is also a widely reported risk factor for schizophrenia and is particularly marked for the subgroup with no family history of the disorder. This study examined how these two risk factors covaried in 78 patients with a Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; American Psychiatric Association, 1987) diagnosis of schizophrenia. Eye tracking and birth-month weather were independently assessed. As hypothesized, patients without ETD were significantly more likely to be born in months with intemperate weather (both hot and cold) than either patients with ETD or people in the general population. Etiologic factors associated with severe weather near birth may be important sources of nonfamilial schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Callosal dysfunction in schizophrenia and schizo-affective disorder.

Studies of corpus callosum dysfunction in schizophrenia have typically relied on measures that reveal impairment in commissurotomy patients, but measures that distinguish people with callosal agenesis may be more appropriate. Four of these indexes were included in the present study. Tests of associated movements, cross-localization of touch, interocular transfer of spiral aftereffect, and transfer of blind formboard learning were administered to 18 chronic schizophrenics, 19 schizo-affectives, and 20 normal volunteers. Both schizophrenics and schizo-affectives were impaired on all measures except transfer of blind formboard learning. Schizophrenics also made significantly more associated movements than schizo-affectives and exhibited a different pattern of cross-localization deficit. These results support the hypothesis of developmental callosal dysfunction in schizophrenia and schizo-affective disorder, although the nature of this dysfunction differs in part from that exhibited by acallosals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional capacity dysfunction and arousal in schizophrenia.

Criticizes 2 influential premises underlying most of current research on schizophrenia and attention: (a) belief in the existence of a specific information-processing deficit and (b) acceptance of a framework of "cold cognition." Capacity theory is proposed as an alternative theoretical framework within which the various phenotypically diverse attentional deficits in schizophrenia reflect a deficit in the control function that governs the mobilization and allocation of attention. Attentional deficits, therefore, are most manifest when effortful processing in short-term storage is required. Research on short-term memory processes in schizophrenics shows that the magnitude of the attention deficit correlates positively with the attentional requirements of the cognitive operations involved. The dysfunction is thought to reflect the high levels of arousal characteristic of schizophrenics. Parallels in the performance of schizophrenics and essentially normal but hyperaroused Ss are outlined in support of this hypothesis. The failure to consider the possible mediating effects of hyperarousal in attentional performance of schizophrenics is an omission in the research on schizophrenic cognition. Causality between arousal and information processing is addressed. (101 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies of brain dysfunction in schizophrenia.

The purpose of this paper is to bring to the attention of the psychologist the extensive research literature concerned with the physiological correlates of behavior. Research concerned with the electroencephalographic, histopathological, and biochemical analysis of schizophrenics receives concentrated attention. The review also includes "several psychological and physiological studies which focus specifically on the question of brain disorder in schizophrenia." The studies made within the last twenty to twenty-five years are included. 81-item bibliography. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neurocognitive dysfunction in patients diagnosed with schizophrenia and alcoholism.

The authors administered the Halstead–Reitan Neuropsychological Test Battery to schizophrenic groups with (n?=?54) and without (n?=?217) coexisting alcoholism, nonschizophrenic groups with alcoholism (n?=?231), and a patient comparison group (n?=?145) to determine the extent of additive cognitive impairment in schizophrenia associated with alcoholism and to compare cognitive function in alcoholism and schizophrenia. The additive effects of alcoholism on cognitive dysfunction in schizophrenia were subtle but were consistently identifiable. Cognitive dysfunction in alcoholism was less severe than in schizophrenia with or without alcoholism. The magnitude of additive effects of alcoholism on cognitive dysfunction in schizophrenia was age related with a significant interaction between age and presence or absence of alcoholism on a global index of cognitive dysfunction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multivariate study of attention dysfunction in schizophrenia.

Administered 5 tests purported to measure attention dysfunction to 60 schizophrenic and 60 nonschizophrenic male psychiatric patients. There was 30 chronic and 30 acute Ss in each group. The measures used were: size estimation, reaction time, and vigilance tasks, the Goldstein-Scheerer Object Sorting Test, and a proverb-interpretation task. Contrary to previous assumptions, these tests did not intercorrelate highly. In addition, individual-difference variables, as measured by staff ratings on the Psychotic Reaction Profile, failed to correlate significantly with task performance. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental and clinical neuropsychological measures of prefrontal dysfunction in schizophrenia.

Eighteen chronic schizophrenia patients and 14 controls were given tests that have been linked primarily to ventral (orbitofrontal) or to dorsolateral prefrontal dysfunctions in neurological patients and in nonhuman animal Ss having discrete frontal lesions. Schizophrenia patients were significantly impaired on object alternation and delayed alternation tasks but not on classical delayed response (DR). Schizophrenia patients performed well on the classical version of the DR task and their DR performance correlated significantly with measures of sustained attention. Future research is needed to interpret the contributions of attention, interference, and memory load to neuropsychological performance in schizophrenia. Additional studies are required to determine whether the frontal deficits reflect diffuse brain damage, circumscribed prefrontal damage, or damage in other brain regions having prefrontal connections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The left hemisphere and the selection of learned actions

The ability of recombinant preparations of equine herpesvirus type 1 (EHV-1) glycoprotein D (gD) to elicit specific antibody and T lymphocyte responses in the BALB/c mouse model of respiratory infection was investigated. Recombinant gD (rgD) expressed as a glutathione-S-transferase (GST) fusion protein in Escherichia coli elicited both high titer neutralizing antibody (nAb) and CD4 T cell proliferative responses following subcutaneous or intranasal immunization, but elicited only a weak antibody response after intraperitoneal immunization. Protection against respiratory tract infection with pathogenic EHV-1 RacL11 was observed in mice immunized subcutaneously with GST-gD. Furthermore, the degree of protection correlated to the titer of nAb and the T cell response observed. Finally, GST-gD was more effective in protecting against respiratory RacL11 infection if delivered intranasally. These results confirm that gD plays an important role in eliciting the protective immune response against EHV-1 infection, and indicate that subunit vaccines containing preparations of gD may be very effective if delivered directly to the upper respiratory tract.     

Relationship between cognitive and social dysfunction in schizophrenia

Cytogenetic monitoring was carried out on a group of 38 nurses who reconstitute antineoplastic drugs in order to determine the extent of chromosomal damage. Genotoxic activities of antineoplastic drugs are studied by chromosome aberration assay, micronucleus assay, sister chromatid exchange (SCE) frequency high frequency cells (HFC) analysis, and mitotic activity of peripheral lymphocytes. Results confirmed that occupational exposure to a mixture of antineoplastic drugs may cause genome damages. The results of this study show that biomonitoring after exposure to a mixture of antineoplastic drugs which express clastogenic and aneugenic activity should involve a battery of cytogenetic methods.     

Response-monitoring dysfunction in schizophrenia: An event-related brain potential study.

Error-monitoring abnormalities may underlie positive symptoms of schizophrenia. Response-synchronized event-related potentials during picture-word matching yielded error- and correct-response-related negativity (ERN, CRN) and positivity (Pe, Pc) and preresponse lateralized readiness potentials (LRP) from 18 schizophrenic patients and 18 controls. Both groups responded faster to matches than nonmatches, although patients were generally slower and made more errors to nonmatches. Compared with controls, patients, particularly with paranoid subtype, had smaller ERNs and larger CRNs, which were indistinguishable. LRPs showed evidence of more response conflict before errors than before correct responses in controls but not patients. Despite ERN/CRN abnormalities, post-error slowing and Pe were normal in patients, suggesting a dissociation of ERN and error awareness. Anterior cingulate and dorsolateral prefrontal cortical dysfunction in schizophrenia are implicated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorical priming in the cerebral hemispheres: automatic in the left hemisphere, postlexical in the right hemisphere?

Automatic and postlexical semantic processing in the cerebral hemispheres was studied by presenting categorically related but nonassociated word pairs (e.g., TABLE-BED) to the left visual field (LVF) or to the right visual field (RVF) in semantic priming experiments. Experiment 1 examined automatic priming across stimulus onset asynchronies (SOAs) of 165 and 750 ms with a low proportion of related pairs and a low nonword ratio, employing a GO-NOGO lexical decision task. In contrast to an earlier view that a larger range of meanings is automatically activated in the right than in the left hemisphere, priming was observed in the RVF/left hemisphere only. SOA did not exert any effects. In Experiment 2, postlexical semantic matching of the prime and the target was encouraged by requiring subjects to respond to both of them at the same time. Now there was priming in the LVF, suggesting that a postlexical matching process works in the right hemisphere. The earlier studies showing a right hemisphere advantage in categorical priming are reinterpreted according to the postlexical right hemisphere hypothesis.     

Left hemisphere specialization for response to positive emotional expressions: A divided output methodology.

An extensive literature credits the right hemisphere with dominance for processing emotion. Conflicting literature finds left hemisphere dominance for positive emotions. This conflict may be resolved by attending to processing stage. A divided output (bimanual) reaction time paradigm in which response hand was varied for emotion (angry; happy) in Experiments 1 and 2 and for gender (male; female) in Experiment 3 focused on response to emotion rather than perception. In Experiments 1 and 2, reaction time was shorter when right-hand responses indicated a happy face and left-hand responses an angry face, as compared to reversed assignment. This dissociation did not obtain with incidental emotion (Experiment 3). Results support the view that response preparation to positive emotional stimuli is left lateralized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bipolar disorder following a stroke involving the left hemisphere

OBJECTIVE: Post-stroke mania has rarely been noted and researched, and reported cases have mostly involved the non-dominant hemisphere. In this paper, we report a case of bipolar disorder secondary to a stroke over the dominant hemisphere. CLINICAL PICTURE: A 48-year-old, right-handed man had a cerebral infarct over the left temporal region. He became depressed after the stroke, and 4 months later developed a manic episode. TREATMENT: The patient was treated with haloperidol and lorazepam. OUTCOME: The symptoms subsided within 2 months after treatment. CONCLUSIONS: It is premature to consider mania to be a syndrome of the right, or non-dominant, hemisphere. We suggest that further study focusing on specific anatomical regions, rather than laterality, will help to elucidate the interrelationship between mood and brain function.     

Functional outcome assessment of aphasia following left hemisphere stroke

This article discusses issues regarding the assessment of functional outcomes in individuals who have aphasia following stroke. Some different approaches to functional outcome measurement are critically reviewed, ranging from general measures of stroke outcome to measures that have been designed specifically for aphasic individuals, to measurements focusing on aphasia's effects on quality of life. Examples of how to relate treatment of aphasia directly to functional outcomes assessment are also provided.     

The genetics and biology of true love: Prosocial biological affects and the left hemisphere.

J. R. Gray (2002) questioned the conceptual basis and empirical support for prosocial biological affects and was skeptical whether the distinction between selfish versus prosocial biological affects can contribute to the discussion regarding hemispheric differences. In reply, hemispheric differences in emotional experience and expression are considered, with the suggestion that the individualist-prosocial distinction may indeed provide a useful addition to traditional higher-level cognitive approaches. Recent empirical evidence relating to prosocial biological affects and emotions is reviewed, and the conceptual basis for prosocial biological affects and emotions is expanded on, with particular reference to answering "selfish gene" conceptualizations. Related genes can exist in different individual organisms, forming the basis for an essential and authentic prosociality: genuine altruism or "true love." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversible left atrial dysfunction possibly due to afterload mismatch in patients with left ventricular dysfunction

OBJECTIVE: The aim of this study was to define the clinical-therapeutical approach to endometrial cancer now being followed in some of the most important centers of reference for gynecological cancer in North America by means of a questionnaire. STUDY DESIGN: The questionnaire focused on four principal areas: (1) surgical staging and therapy; (2) adjuvant treatment; (3) treatment modifications; and (4) management of advanced stages (FIGO III-IV). RESULTS: There were 48 evaluable responses (77%) received by the end of December 1994 which were considered for this analysis. Lymphadenectomy is utilized routinely in 26/48 centers (54.2%) and in selective clinical-pathological conditions in another 21/48 centers (43.5%). In the majority of centers (31/48; 64.6%) radical surgery is utilized for selected indications such as cervical involvement. Only 3/48 (6.2%) centers consider the vaginal approach totally inappropriate. The great majority (40/48; 83.3%) of the centers considered postsurgical adjuvant therapy to be necessary in FIGO Stage Ic. Brachytherapy is routinely performed in 3 centers (6.2%) in postsurgical management of Stage I endometrial cancer, while the majority of the centers (31/48; 64.6%) perform brachytherapy of the vaginal vault in certain clinical-pathological conditions. A wide variety of treatments are used for advanced stages (FIGO III-IV). CONCLUSIONS: It emerges that some controversial aspects exist on endometrial cancer treatment, and these conflicting data need a large-scale multicenter randomized clinical trial.