Post-traumatic mutism in children: clinical characteristics, pattern of recovery and clinicopathological correlations

Global aphasia without hemiparesis may be caused by blunt head trauma: An adolescent boy with transient aphasia

Global aphasia without hemiparesis is a rare condition often associated with embolic stroke. Posttraumatic causes have not been reported, in the literature, to our knowledge. We report a 15-year old boy with transient global aphasia without hemiparesis due to blunt head trauma. In our case, clinical findings occurred 1week later following head trauma. Emergence of the symptoms after a period of the first mechanical head trauma, draws attention to the importance of secondary process in traumatic brain injury.

Neural bases of childhood speech disorders: lateralization and plasticity for speech functions during development

Current models of speech production in adults emphasize the crucial role played by the left perisylvian cortex, primary and pre-motor cortices, the basal ganglia, and the cerebellum for normal speech production. Whether similar brain-behaviour relationships and leftward cortical dominance are found in childhood remains unclear. Here we reviewed recent evidence linking motor speech disorders (apraxia of speech and dysarthria) and brain abnormalities in children and adolescents with developmental, progressive, or childhood-acquired conditions. We found no evidence that unilateral damage can result in apraxia of speech, or that left hemisphere lesions are more likely to result in dysarthria than lesion to the right. The few studies reporting on childhood apraxia of speech converged towards morphological, structural, metabolic or epileptic anomalies affecting the basal ganglia, perisylvian and rolandic cortices bilaterally. Persistent dysarthria, similarly, was commonly reported in individuals with syndromes and conditions affecting these same structures bilaterally. In conclusion, for the first time we provide evidence that longterm and severe childhood speech disorders result predominantly from bilateral disruption of the neural networks involved in speech production.

Post-traumatic mutism in children

OBJECTIVE

To explore the pathological mechanism of post-traumatic mutism (PTM) in children.

METHODS

A retrospective study of 16 children who suffered from severe head injury and developed PTM.

RESULTS

Post-traumatic coma lasted from 2-72 days, average 15.5 days; while post-traumatic mutism lasted from 2-56 days, average 11.94 days. The correlation between duration of coma and mutism was significant (p < 0.001). SPECT found that multiple persistent ischaemic brain regions occurred in all patients; the mean number of regions was 5.6. The patients were sub-divided into three groups based on the number of ischaemic regions: group 1, < or = 4; group 2, 5 approximately 6; group 3, > or = 7. The duration of mutism did not differ significantly between groups 1 and 2, but the difference between group 3 and the other two groups combined was significant (p < 0.05).

CONCLUSION

Most PTM occurred in patients with diffuse brain injury. The duration of mutism was related to the number of ischaemic brain regions and the duration of post-traumatic coma.

Models of traumatic cerebellar injury

Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Studies of human TBI demonstrate that the cerebellum is sometimes affected even when the initial mechanical insult is directed to the cerebral cortex. Some of the components of TBI, including ataxia, postural instability, tremor, impairments in balance and fine motor skills, and even cognitive deficits, may be attributed in part to cerebellar damage. Animal models of TBI have begun to explore the vulnerability of the cerebellum. In this paper, we review the clinical presentation, pathogenesis, and putative mechanisms underlying cerebellar damage with an emphasis on experimental models that have been used to further elucidate this poorly understood but important aspect of TBI. Animal models of indirect (supratentorial) trauma to the cerebellum, including fluid percussion, controlled cortical impact, weight drop impact acceleration, and rotational acceleration injuries, are considered. In addition, we describe models that produce direct trauma to the cerebellum as well as those that reproduce specific components of TBI including axotomy, stab injury, in vitro stretch injury, and excitotoxicity. Overall, these models reveal robust characteristics of cerebellar damage including regionally specific Purkinje cell injury or loss, activation of glia in a distinct spatial pattern, and traumatic axonal injury. Further research is needed to better understand the mechanisms underlying the pathogenesis of cerebellar trauma, and the experimental models discussed here offer an important first step toward achieving that objective.

Speech Rate and Fluency in Children and Adolescents

Reduced speech fluency is frequent in clinical paediatric populations, an unexplained finding. To investigate age related effects on speech fluency variables, we analysed samples of narrative speech (picture description) of 308 healthy children, aged 5 to 17 years, and studied its relation with verbal fluency tasks. All studied measures showed significant developmental effects. Speech rate and verbal fluency scores increased, while pauses, repetitions and locution time declined with age. Speech rate correlated with semantic fluency tasks suggesting that it also depends upon the efficacy of lexical retrieval. These results indicate that the interpretation of disorders of speech fluency in childhood must incorporate age appropriate norms.

Transient cerebellar mutism caused by bilateral damage to the dentate nuclei after the second posterior fossa surgery. Case report

The authors report on the case of a 6-year-old boy who underwent resection of a midline cerebellar tumor. The boy was able to speak fluently after the operation. Magnetic resonance (MR) imaging showed that the right dentate nucleus had been partially removed along with the tumor, but that the left dentate nucleus remained with the residual tumor. A second operation was performed to remove the residue, after which the child suffered mutism. Three weeks post-surgery, he could only communicate through gestures. He started speaking I week later and regained normal speech 2 months after the operation. Final MR imaging revealed gross-total removal of the tumor and dentate nucleus on the injured left side. The cerebellar mutism was considered to have been caused by bilateral damage to the dentate nuclei and not by unilateral damage.