Early computed tomography for acute post-traumatic diffuse axonal injury: a systematic review.

PURPOSE: Diffuse axonal injury (DAI) is the rupture of multiple axons due to acceleration and deceleration forces during a closed head injury. Most traumatic brain injuries (TBI) have some degree of DAI, especially severe TBI. Computed tomography (CT) remains the first imaging test performed in the acute phase of TBI, but has low sensitivity for detecting DAI, since DAI is a cellular lesion. The aim of this study is to search in the literature for CT signs, in the first 24 h after TBI, that may help to differentiate patients in groups with a better versus worst prognosis. METHODS: We searched for primary scientific articles in the PubMed database, in English, indexed since January 1st, 2000. RESULTS: Five articles were selected for review. In the DAI group, traffic accidents accounted 70% of the cases, 79% were male, and the mean age was 41 years. There was an association between DAI and intraventricular hemorrhage (IVH) and traumatic subarachnoid hemorrhage (tSAH); an association between the IVH grade and number of corpus callosum lesions; and an association between blood in the interpeduncular cisterns (IPC) and brainstem lesions. CONCLUSION: In closed TBI with no tSAH, severe DAI is unlikely. Similarly, in the absence of IVH, any DAI is unlikely. If there is IVH, patients generally are clinically worse; and the more ventricles affected, the worse the prognosis.

Magnetic resonance imaging (MRI) findings and neuropsychological sequelae in children after severe traumatic brain injury: the role of cerebellar lesion.

We studied the relationships between magnetic resonance imaging (MRI) findings and neuropsychological sequelae in children after severe traumatic brain injury. Twenty-three children ages 7-13 years underwent MRI assessment of brain lesion topography and volume and neuropsychological evaluations, more than 1 year after sustaining severe traumatic brain injury. Most children had lesions to the corpus callosum and frontal lobes. Total lesion volume and extent of cerebral atrophy did not impact on the neuropsychological evaluation. Additional relationships were observed: left frontal lesions with lower semantic verbal fluency, right occipital lesions with lower visual recognition task scores, dyscalculia with cerebellar lesions, and cerebellar damage with lower cognitive performances and lower visual recognition memory. This study demonstrates the significance of the cerebellum's role in neuropsychological outcomes after traumatic brain injury and the importance of the lesion depth classification in predicting functional results.

Alteraciones estructurales en el cuerpo calloso: diagnóstico ecográfico / Structural alterations of the corpus callosum: diagnosed by ultrasound

Uso de ecografía en la detección de lesiones del cuerpo calloso: agenesia total y parcial, disgenesia y displasia, o lesiones secundarias. Esta práctica permite relacionarlas con patologías en el recién nacido y el lactante, al conocer su evolución embriológica y su ubicación anatómica.(AU)

Neonatal transection of the corpus callosum affects rotational side preference in adult Swiss mice.

In order to test the hypothesis that the ontogenetic development of the corpus callosum (CC) contributes to the establishment of behavioral lateralization, the rotatory behavior in the free-swimming test was studied in male Swiss mice that were subjected to mid-sagittal transection of the CC during the first postnatal day. At adulthood, 16 Acallosal and 30 Sham-operated mice were submitted to 3 sessions of the free-swimming rotatory test (diameter of the recipient=21 cm; session duration=5 min; inter-test interval=48 h). The number and direction of 30 degrees turns were recorded. Our results indicate that transected animals became progressively more lateralized than Sham ones from the first to the third session. This difference between groups was explained mainly by the more pronounced reduction in turning activity to the non-preferred side along the sessions that was observed in Acallosal mice. Our results give further support to the hypothesis that the normal development of the CC is related to the establishment of brain asymmetries in general and behavioral lateralization in particular.

Neonatal transection of the corpus callosum affects paw preference lateralization of adult Swiss mice.

In the present work, the hypothesis that the ontogenetic development of the corpus callosum (CC) affects the establishment of behavioral lateralization was tested by studying paw preference performance in adult Swiss mice that were subjected to mid-sagittal transection of the CC on the first postnatal day. Magnitude and direction of laterality were evaluated independently. No significant differences between groups were found for the magnitude of paw preference. On the other hand, the transected group presented a significant populational bias favoring the left paw that was not present in the control groups. These results lend support to the hypothesis that the development of the CC plays a role in the establishment of the normal pattern of behavioral lateralization.

The case for a relationship between human memory, hippocampus and corpus callosum.

Unilateral brain damage which includes the hippocampus leads to memory impairments consistent with hemispheric specialization on the same side. Damage to the corpus callosum, the major connecting pathway between the left and right hemispheres, also leads to memory impairments. This suggests both hemispheric specialization on the hippocampal level and a critical role for the corpus callosum in memory functions. A complete hippocampal formation is present on either side of the brain but traditionally only one is studied. However, a comparison between the neuronal populations in the hippocampus on both sides revealed asymmetry in connectivity among hippocampal subfields. The profile of memory impairments of commissurotomy ('split-brain') patients is described. The results are discussed in terms of a relationship between hippocampus and corpus callosum in humans. As hemispheric specialization evolved, inter-hippocampal connections became less important and the corpus callosum became prominent in memory functions.

Traumatic callosotomy

Uma paciente epiléptica jovem foi vítima de queda de certa altura após crise tônico-clônica generalizada. Foi admitida em coma no Setor de Emergência. Sua investigaçäo clínico-radiológica mostrou presença de hematomas interhemisféricos, extensa secçäo traumática do corpo caloso e contusöes fronto-basais. A despeito de hemiparesia residual, sua investigaçäo neuropsicológica näo mostrou sinais de desconexäo hemisférica, compatível à integridade da regiäo do esplênio ao exame de RMN. Após o trauma, a paciente apresentou grande melhora da síndrome epiléptica. O papel relativo de cada uma das lesöes traumáticas é difícil de ser inferido, em se tratando de lesäo cerebral múltipla. O provável mecanismo fisiolpatológico deve incluir impacto direto do corpo caloso contra a foice, além de mecanismos de aceleraçäo/desaceleraçäo

Traumatic callosotomy.

In a 33 years-old epileptic woman with a traumatic impact to the vertex, clinical and radiological studies (skull X-R, CT and MRI) disclosed an extensive callosal section under the topography of the falx, associated to fronto-basal contusions. There was a significant improvement in the epileptic syndrome. No interhemispheric disconnection syndrome could be determined, which is compatible with the posterior regions of the corpus callosum having been spared. This is, to the best of our knowledge, the most extensive callosal injury documented by MRI to date.