Investigators at UCL Institute of Neurology, Queen Square, London, UK, used functional magnetic resonance imaging to study the effect of cognitive effort during a working memory task as a trigger of myoclonic jerks in 15 unaffected siblings (10 female; age range 18-65 years, median 40 yrs) of 11 patients with juvenile myoclonic epilepsy (6 female; age range 22-54 yrs, median 35). fMRI activations were compared with 20 age- and gender-matched healthy control subjects.

Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to that in patients with JME (P < 0.001). This finding in unaffected siblings suggests a mechanism for impairment of frontal lobe functions in both patients and siblings, independent of effects of medication or seizure, an endophenotype of JME. [1]

COMMENTARY. The abnormal frontal lobe function demonstrated by fMRI in adults with JME and their siblings is also demonstrated in children.

Neurodevelopment in new-onset juvenile myoclonic epilepsy. Investigators at Irvine University, CA, studied the maturation of cognitive and brain development in 19 children with new-onset JME in the first 2 years after diagnosis and 57 healthy controls. Abnormal patterns of brain development affecting frontoparietotemporal regions, as assessed by MRI, were evident in children with JME and included attenuation of age-related decline in cortical volume, thickness, and surface area. Children with JME have abnormal structural brain development and impaired cognitive development early in the course of the epilepsy [2].