Cognitive, Sensory and Motor Adjustment to Hemispherectomy. In: Jambaqué I, Lassonde M, Dulac O, editors. Neuropsychology of Childhood Epilepsy. Boston: Springer US; 2001. pp. 229-44. [DOI: 10.1007/0-306-47612-6_25]

The hidden face of hemispherectomy: Visuo-spatial and visuo-perceptive processing after left or right functional hemispherectomy in 40 children

Functional hemispherectomy results in good outcomes in cases of refractory epilepsy and constitutes a unique situation in which to study cerebral plasticity and the reorganization of lateralized functions of the brain, especially in cases of infancy or childhood surgery. Previous studies have highlighted the remarkable ability of the brain to recover language after left hemispherectomy. This leads to a reorganization of language networks toward right hemisphere, causing limitation in the development of visuo-spatial abilities, known as a crowding effect in the right hemisphere. Deficits in nonverbal functions have also been described as a more direct consequence of right hemipherectomy, but the results from case studies have sometimes been contradictory. We conducted a group study which may effectively compare patients with left and right hemispherectomy and address the effects of the age of seizure onset and surgery. We analyzed the general visuo-spatial and visuo-perceptive abilities, including face and emotional facial expression processing, in a group of 40 patients aged 7-16 years with left (n = 24) or right (n = 16) functional hemispherectomy. Although the groups did not differ, on average, in general visuo-spatial and visuo-perceptive skills, patients with right hemispherectomy were more impaired in the processing of faces and emotional facial expressions compared with patients with left hemispherectomy. This may reflect a specific deficit in the perceptual processing of faces after right hemispherectomy. Results are discussed in terms of limited plasticity of the left hemisphere for facial and configural processing.

Exceptional verbal intelligence after hemispherotomy in a child with Rasmussen encephalitis

We report a longitudinal case study of a left-handed girl who underwent left hemispherotomy at 7 years for Rasmussen encephalitis (RE). Presurgical evaluation showed mild hemiparesis, no visual defect, and light neuropsychological impairment with short-term memory weakness. Language fMRI showed a right hemispheric dominance. Postoperatively, the patient exhibited right hemiplegia and hemianopsia but preserved intellectual capacities. She became seizure-free, and antiepileptic medication was discontinued. Long-term follow-up showed very high verbal intelligence at 11 years of age (VCI of 155) and improvement in working memory as well as language and reading abilities. Furthermore, a significant visuoverbal discrepancy became increasingly pronounced. Thus, early surgical treatment of epilepsy avoided the global cognitive deterioration usually associated with RE. Finally, such a high level of verbal functioning combined with low spatial reasoning with a single hemisphere provides additional information on the neurocognitive profile of children with RE after hemispherotomy.

Epilepsy surgery in children with drug-resistant epilepsy, a long-term follow-up

OBJECTIVES

In this follow-up study, we wanted to present the long-term outcome (5-21 years) in terms of seizure freedom, seizure reduction, and the cognitive development in the first 47 children who underwent epilepsy surgery at the University Hospital in Lund from 1991 to 2007.

MATERIALS AND METHODS

All children who underwent epilepsy surgery in the southern region of Sweden were assessed for cognitive function before surgery and at follow-up. A review of medical documents for demographic data and seizure-related characteristics was made by retrospectively examining the clinical records.

RESULTS

Forty-seven children with a median age at surgery of 8 years (range 0.5-18.7 years) were included. Twenty-three children achieved seizure freedom, six demonstrated >75% improvement in seizure frequency, and none of the children experienced an increase in seizure frequency. Twenty-one children required a reoperation to achieve satisfactory seizure outcomes. Cognitive functional level was preserved, and the majority of patients, 34 (76%), followed their expected cognitive trajectory. The patients who became seizure free significantly improved their cognitive processing speed, even after long-term follow-up.

CONCLUSIONS

Epilepsy surgery in children offers suitable candidates a good chance of significantly improved outcome and low rates of complications. Several children, however, required a reoperation to achieve satisfactory seizure outcomes. Cognitive level was preserved, and the majority of patients followed their expected cognitive trajectory. Cognitive improvements in processing speed appear to occur in parallel with seizure control and were even more pronounced in subjects with no anti-epilepsy drugs. These improvements persisted even after long-term follow-up.

Hemispherotomy and other disconnective techniques

The surgical treatment of intractable epilepsy has evolved as new technical innovations have been made. Hemispherotomy techniques have been developed to replace hemispherectomy in order to reduce the complication rates while maintaining good seizure control. Disconnective procedures are based on the interruption of the epileptic network rather than the removal of the epileptogenic zone. They can be applied to hemispheric pathologies, leading to hemispherotomy, but they can also be applied to posterior quadrant epilepsies, or hypothalamic hamartomas. In this paper, the authors review the literature, present an overview of the historical background, and discuss the different techniques along with their outcomes and complications.

Launching a research initiative: the Canadian Pediatric Epilepsy Network (CPEN)

The Canadian Pediatric Epilepsy Network is a network of scientists and health care professionals in partnership with organizations which provide education and support to children with epilepsy. The objective of the network is to gain a better understanding of childhood epilepsy through collaborative research conducted with doctors, psychologists, nurses, social workers, educators and scientists across Canada. The network was launched at a meeting in Ottawa in the spring of 2000 where several oral presentations addressed the issues of the fundamental questions of epilepsy, the economic impact and the neuropsychology of childhood epilepsy. The intent was to provoke discussion on future areas of research for the network.