Case study: A patient with agenesis of the corpus callosum with minimal associated neuropsychological impairment

This is a case study of an 88-year-old man who presented with agenesis of the corpus callosum and colpocephaly. Symptomatically, he reported a sudden onset of mild, intermittent left hand apraxia, but denied any previous manifestations consistent with this type of brain malformation. The patient underwent neuroimaging, evaluation by neurology, and comprehensive neuropsychological testing to determine the nature of any other associated impairments. Test results indicated that he was, with a few exceptions, neuropsychologically normal. He performed well on tests that are highly sensitive to acquired brain dysfunction. His most notable deficit was failed performance in the simultaneous and coordinated use of both hands in using tactile and proprioceptive feedback on the Tactual Performance Test. This case is discussed in terms of plasticity of the developing brain, including compensatory mechanisms, highlighting the variability in clinical outcome in the context of congenital brain malformation. This case study illustrates the strong influence of cerebral plasticity as well as a possible circumscribed manifestation of interhemispheric disconnection.     

Comprehension of humor in primary agenesis of the corpus callosum

Individuals with agenesis of the corpus callosum (ACC) can, in some cases, perform normally on standardized intelligence tests. Nevertheless, recent studies suggest that individuals with ACC and normal IQ scores have deficits in domains of fluid and social intelligence. Anecdotal reports from families suggest diminished appreciation of the subtleties of social interactions, and deficits in the comprehension of jokes and stories. In this research, both the cartoon and narrative joke subtests of a humor test (developed by Brownell et al. [Brownell, H., Michel, D., Powelson, J., & Gardner, H. (1983). Surprise but not coherence: sensitivity to verbal humor in right-hemisphere patients. Brain and language, 18(1), 20-27] and Bihrle et al. [Bihrle, A. M., Brownell, H. H., Powelson, J. A., & Gardner, H. (1986). Comprehension of humorous and non-humorous materials by left and right brain-damaged patients. Brain and Cognition, 5(4), 399-411]) were given to 16 adults with complete ACC (all with IQs>80) and 31 controls of similar age and IQ. Individuals with ACC performed worse than controls on the narrative joke subtest (p<.025) when VIQ was controlled. However, on the cartoon subtest the two groups were not significantly different. Covarying age, forms of IQ, narrative memory, set-switching, and literal language comprehension did not substantially alter the group difference. However, covarying comprehension of nonliteral language and proverbs eliminated the difference, suggesting a common origin for the comprehension of jokes, nonliteral language, and proverbs, most likely related to capacity for understanding second-order meanings.     

Alexithymia and somatization in agenesis of the corpus callosum

Deficient communication between the cerebral hemispheres is one of several prevailing neurobiological explanations for alexithymia and has been strongly supported by research on patients with commissurotomy. We examined self-reported symptoms of alexithymia in adults with agenesis of the corpus callosum (AgCC), a condition characterized by more subtle reductions in interhemispheric transfer than in commissurotomy. Sixteen adults with AgCC and full-scale intelligence quotient >80 were compared with 15 neurotypical controls group-matched for age and intelligence score. The AgCC group endorsed greater difficulty identifying and describing feelings and more vague physical symptoms than controls but similar levels of emotional experience and emotional coping. This finding of impaired emotional interpretation with intact emotional experience is consistent with findings in callosotomy patients, implicating the critical role of the corpus callosum in cognitive dimensions of emotion processing. Further study of alexithymia in AgCC using task-based measures may help clarify the nature of this relationship.     

Precocious cerebral development associated with agenesis of the corpus callosum in mid-fetal life: a transient syndrome?

Four fetal brains are described in which the cerebrum showed precocious sulcus formation. The fetuses were 14, 17, 18 (15), and 19 (15–16) weeks of gestational age (age in parentheses according to developmental parameters). Associated lesions were characterized by insufficient insular formation and agenesis of the corpus callosum. Cases 1 and 3 had no familial anomalies, while a sib of case 2 had rhombencephalic malformations and a sib of case 4 lissencephaly. Case 2 showed further brain malformation including a migration disorder in the cerebrum and case 3 was associated with a Turner syndrome. The precociously formed sulci may be covered during further development of the brain so that this may well be a transient syndrome that occurs in mid-fetal life. Received: 13 June 1995 / Revised, accepted: 8 September 1995     

Monozygotic twin cases of the agenesis of the corpus callosum with schizophrenic disorder

We report the identical monozygotic twin cases of agenesis of the corpus callosum that demonstrated schizophrenic disorder. Patients were 26-year-old twin brothers and both cases were diagnosed as having schizophrenia using DSM-III-R diagnostic criteria. On magnetic resonance imagings both cases demonstrated the total agenesis of the corpus callosum and the anterior commissure was hypertrophic. We speculated that the developmental disturbance of the corpus callosum might be related to the cause of the psychiatric disorders in the present cases.     

胼胝体动静脉畸形

本文报告１９例胼胝体动静脉畸形（ＡＶＭ），２０个病灶（１例多发）。其中，膝部３个，体部２个，压部１５个，所有病人都有蛛网膜下腔出血，而以癫痫大发作为首症状者仅１例，以胼周动脉为主要供血动脉，大脑后动脉分支亦参与供血，除１例行供血动脉结扎术外，其余１９个ＡＶＭ均采用显微外科手术完整切除，无死亡，手术疗效满意。     

1例外伤性胼胝体出血报告

1病例资料 患者,女性,64岁,农民,因外伤后头痛、呕吐、左侧肢体无力1d余入院。患者入院前1d不慎摔倒,当时后枕部着地,随即出现头痛,为后枕部及右侧头部胀痛,伴恶心、呕吐,呕吐呈非喷射性,呕吐物为胃内容物,自行站起后又多次摔倒,后行走约1km回家,到家后仍头痛,频繁呕吐,     

Facial emotion recognition in patients with schizophrenia and their siblings

Background: Deficits in recognition of facial emotions have been widely reported in patients with schizophrenia. Previous studies that examined recognition of facial emotions in relatives of patients with schizophrenia brought out inconsistent results. Aims: In this study, we aimed to examine facial emotion identification and discrimination abilities in patients with schizophrenia and their healthy siblings to find out whether familial vulnerability to schizophrenia is associated with deficits in facial emotion recognition. Methods: Patients with schizophrenia (n=57), their unaffected biological siblings (n=58) and healthy controls (n=58) were included in the study. The three groups did not differ significantly for gender, age and education level. All the participants were evaluated with the Facial Emotion Identification Test (FEIT) and Facial Emotion Discrimination Test (FEDT). Results: Patients with schizophrenia performed significantly worse than controls on FEIT and FEDT. Siblings performed significantly better than patients and significantly worse than controls on FEIT and FEDT. Conclusions: Impaired performance of siblings on facial emotion identification and discrimination tasks provides evidence for the hypothesis that facial emotion recognition deficits are transmitted in families and may represent a heritable endophenotype of schizophrenia.     

A disconnection syndrome due to agenesis of the corpus callosum: disturbance of unilateral synchronization

Recently, interhemispheric disconnection syndromes have been noted in patients with agenesis of the corpus callosum (ACC) during the performance of certain tasks. However, few studies have demonstrated an asymmetric disconnection syndrome. In this report, we present just such a syndrome in a patient with ACC, who manifested ambidexterity (but with a left-hand tendency) and had high intelligence, no neurological deficits, and no associated malformations. In a comparison with similar subjects (amateur musician), we studied her asymmetric deficits using four tasks: (1) simple reaction time for visual stimuli, (2) paced finger tapping in synchrony with visual or auditory stimuli, (3) paced finger tapping without an external reference, and (4) rhythmical finger tapping in synchrony with visual or auditory stimuli. While the comparable subjects displayed no significant difference between hands, and the patient showed no significant difference between hands in the auditory paradigm, her tapping performance deteriorated significantly when asked to synchronize the left hand with timed visual stimuli, irrespective of whether finger tapping was paced or rhythmical. We believe that this phenomenon constitutes a novel asymmetrical disconnection syndrome in an ACC subject; these results suggest that synchronization of multimodal temporal information was lateralized in the left hemisphere (in this case), which is something that the ACC patient could not compensate for.     

以失用为主要表现的胼胝体梗死

目的探讨胼胝体梗死的临床表现、病因及鉴别诊断特点。方法对2005年7月收治的1例53岁男性胼胝体梗死患者的临床表现、影像学特点、病因机制及其治疗过程进行回顾分析。结果临床主要表现为发作性黑蒙、言语不利,既往有高血压、糖尿病、脑梗死、吸烟、饮酒史,体格检查以失用为主要表现。头部MRI检查可见左侧脑室旁、胼胝体梗死,右侧基底节、脑桥陈旧性腔隙性梗死;脑血管造影检查显示为多发性血管狭窄,其中以左侧大脑中动脉、右侧颈内动脉及基底动脉最为严重。经颈内动脉内膜剥离术及颈内动脉支架植入术治疗,临床症状缓解。结论失用可以是胼胝体梗死的主要表现,其病因是在脑动脉粥样硬化基础上的血流动力学改变,患者预后良好。     

“蝴蝶状”胼胝体胶质瘤的显微手术治疗

目的探讨MRI表现呈典型“蝴蝶状”改变的胼胝体胶质瘤的临床特点,以及不同部位肿瘤的显微手术切除方法及其预后。方法收集整理2003年至2008年期间,于我院住院并显微手术治疗的35例MRI表现呈“蝴蝶状”胼胝体胶质瘤患者的临床资料进行回顾性分析。结果手术全切27例,次全切8例。术后癫痫发作2例,瘫痪1例,死亡1例,31例术后恢复良好。30例随访6个月至5年,平均生存期16个月。结论通过MRI术前精确定位,对不同部位的“蝴蝶状”胼胝体胶质瘤选择恰当的手术人路,显微镜下行全切或次全切是可行的,大多数病例能取得良好的临床效果。     

The morphology of the corpus callosum in schizophrenia: An MRI study

40 schizophrenic patients and 17 normal controls underwent magnetic resonance imaging (MRI) of the brain. All subjects were consenting males. The size and form of the corpus callosum in the mid-sagittal cut of MRI were evaluated. This study revealed that the mean size of the anterior region of the corpus callosum was significantly greater in schizophrenics than in controls. The elongated anterior corpus callosum, which did not correlate with age, duration of illness, birth complications or any measures of brain areas in the midsagittal cut, was regarded as a primary change. Schizophrenics with the elongated corpus callosum seemed to have an unfavorable prognosis, because the large corpus callosum suggested poor heterosexual relations, reduced number of hospitalizations, low academic grades and mild anxiety-depression syndrome. A smooth and even corpus callosum seen in schizophrenics was likely a change dependent on duration of illness.     

Agenesis of corpus callosum: prenatal diagnosis and prognosis

Introduction Agenesis of corpus callosum (ACC) is commonly diagnosed prenatally. When isolated, it appears to carry a good prognosis but studies are often retrospective and follow-up short. We report a prospective study of 17 children (11 boys, 6 girls) with prenatally diagnosed isolated ACC.Methods Neuropsychological evaluation was performed each year and results at the ages of 2, 4, and 6 years were compared.Results Febrile seizures occurred in 3 patients. Median intellectual quotient (IQ) was within the normal range (80–109) and nonrelated to partial or complete ACC, sex, or febrile seizures. Lower median IQ was significantly related to low cultural status. With age, the number of children with IQ in the lower range (80–89) increased and slowness, attentional troubles, and instability appeared.Conclusion This study demonstrates that if outcome of isolated ACC is favorable, a long follow-up is necessary: with age, IQ in the lower range and behavioral troubles are linked to difficulties in school.     

Crossed aphasia following an infarction in the right corpus callosum

A 68-year-old right-handed woman with no history of brain damage or familial left-handedness was admitted to our hospital due to the acute onset of speech difficulty; her speech was nonfluent. Literal and phonological paraphasias, agrammatism and paragrammatism were observed. Brain MRI revealed an acute infarction in the right anterior cerebral artery territory, involving the right corpus callosum. Moreover, cerebral blood flow was decreased not only in the area of the right corpus callosum but also in the left fronto-temporal lobe, suggesting crossed diaschisis. This is a rare case of crossed aphasia following an infarction in the right corpus callosum.     

胼胝体梗死所致的发作性拮抗性失用

目的 探讨胼胝体梗死引起拮抗性失用的特点和机制.方法 对1例表现为发作性拮抗性失用的患者,分别进行神经心理、头颅磁共振、颈CT血管成像检查.结果 神经心理检查提示为拮抗性失用,头MRI示右侧胼胝体梗死,予抗血小板,改善脑循环治疗后发作减少.结论 胼胝体梗死可以引起发作性拮抗性失用为特征的神经心理症状.

Abstract：

Objectives To report the clinical features and treatment in a case with paroxysmal diagonistic ideomotor apraxia after ischemic infarction of the corpus callosum.Methods The neuropsychological tests,brain MRI,the TCD and carotid duplex sonography were carried out in the patient who is right handed and had had presentation of paroxysmal diagonistic ideomotor apraxia for ten days.Results Neuropsychological tests confirmed the diagnosis of paroxysmal diagonistic apraxia in this patient.MRI showed ischemic infarction in the right corpus callosum.The symptomsin the patient were improved after the treatment with aspirin for three months.Conclusion The infarction of corpus callosum may induce paroxysmal diagonistic apraxia.     

Social cognition in individuals with agenesis of the corpus callosum

Past research has revealed that individuals with agenesis of the corpus callosum (ACC) have deficits in interhemispheric transfer, complex novel problem-solving, and the comprehension of paralinguistic aspects of language. Case studies and family reports also suggest problems in social cognition. The performance of 11 individuals with complete ACC and with normal intelligence was compared to that of 13 IQ- and age-matched controls on three measures of social cognition. Individuals with ACC were indistinguishable from controls on the Happé Theory of Mind Stories and the Adult Faux Pas Test, but performed significantly worse on various portions of the Thames Awareness of Social Inference Test (TASIT) involving interpretations of videotaped social vignettes. Further analysis of the TASIT indicated that individuals with ACC showed deficiency in the recognition of emotion, weakness in understanding paradoxical sarcasm, and particular difficulty interpreting textual versus visual social cues. These results suggest that the tendency for deficient social cognition in individuals with ACC stems from a combination of difficulty integrating information from multiple sources, using paralinguistic cues for emotion, and understanding nonliteral speech. Together, these deficits would contribute to a less robust theory of mind.     

Classical disconnection studies of the corpus callosum

The corpus callosum is one of the most prominent fiber systems of the mammalian brain. Early reports of animals in which the callosum was cut, often confused the effects attributable to callosum damage with those caused by lesions of other brain structures. Early clinical reports also failed to establish the role of the callosum in humans. Two sorts of evidence began to reveal the functions of the corpus callosum. People with callosal damage cannot read text presented in the left visual field, and animals in which the callosum is divided, and sensory input restricted to one hemisphere, fail to show interhemispheric transfer of learning. These functional findings are consistent with anatomical and physiological studies of the role of the corpus callosum in communication between the hemispheres.     

A factor analysis of the rat''s corpus callosum

Previous work from our laboratory (Berrebi et al., Brain Research, 438 (1988) 216-224) demonstrated region-specific sexual dimorphisms in the size of the rat's corpus callosum, which are modifiable by extra stimulation in early life. These differences are assumed to reflect regional corticocortical fibers of passage which are altered differentially by gender and our experimental manipulations. In this paper, we report our findings when the original data are reanalyzed using a newly developed computer program. This program not only reproduced, with very high accuracy, the original means, but also permitted us to examine computer generated callosal width scores via a factor analysis procedure. Such a procedure yields useful information concerning the clustering of callosal fibers and thus contributes significantly to our hypothesis that discrete cortical regions are selectively sensitive to experimental variables. Factor analyses of the callosal variables and brain weight of 155 rats found 7 width factors, and an eighth factor which contained the variables of brain weight, callosal length, and callosal perimeter. Callosal area did not load significantly on any of these factors. The percentile locations of the width factors, starting at the anterior (genu) end were: widths 1-5, 6-17, 24-38, 46-57, 62-72, 79-95 and 96-99. Use of these factor scores in analyses of variance revealed that the male callosum is wider than the female's, with the differences most pronounced in the genu and the most posterior portion of the splenium. Both age and early handling experience influenced the callosal width factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Meta-analysis of magnetic resonance imaging studies of the corpus callosum in schizophrenia

OBJECTIVES: The corpus callosum plays a pivotal role in inter-hemispheric transfer and integration of information. Magnetic resonance studies have reported callosal abnormalities in schizophrenia but findings have been inconsistent. Uncertainty has persisted despite a meta-analytic evaluation of this structure several years ago. We set out to perform a further meta-analysis with the addition of the numerous reports published on the subject to test the hypothesis that the corpus callosum is abnormal in schizophrenia. METHOD: A systematic search was carried out to identify suitable magnetic resonance studies which reported callosal areas in schizophrenia compared to controls. Results from the retrieved studies were compared in a meta-analysis whilst the influence of biological and clinical variables on effect size was ascertained with meta-regression analysis. RESULTS: Twenty-eight studies were identified. Corpus callosum area was reduced in schizophrenia in comparison to healthy volunteers. This effect was larger in first episode patients. Similarly, heterogeneity detected among the studies was associated with course of illness indicating that chronic subjects with schizophrenia showed larger callosal areas. There was no evidence of publication bias. CONCLUSIONS: This study confirms the presence of reduced callosal areas in schizophrenia. The effect is of a larger magnitude at first presentation and less so in subjects with a chronic course generally medicated with antipsychotics.