[A case of recurrent paraneoplastic cerebellar ataxia with antibodies to GluR epsilon 2 causally related to ganglioneuroma].

Acute cerebellar ataxia (ACA) in childhood following viral infection is a self-limited disease. We present a boy with recurrent episodes of paraneoplastic cerebellar ataxia associated with a ganglioneuroma. A 20-month-old boy developed the first episode of cerebellar ataxia after nonspecific respiratory tract infections. During this episode he showed a wide gait and truncal ataxia with intention tremor and horizontal nystagmus. Our initial diagnosis was ACA, and gradual improvement of ataxia was observed thereafter. At 2 years and 6 months, similar cerebellar symptoms recurred after respiratory tract infections. Speech difficulty and cognitive problems developed thereafter. We suspected paraneoplastic syndrome. Computed tomography revealed a retroperitoneal tumor, and autoantibodies against GluR epsilon 2 were detected in the cerebrospinal fluid. After the tumor resection, the cerebellar symptoms did not recur and speech difficulty and cognitive problems improved gradually. Recent neuroimaging and neuropsychological studies have revealed that cerebellar function contributes to higher brain functions including cognition and learning. We will follow up this patient's long-term cognitive function and consider special educational support and programs.

[Event-related potentials to response production and inhibition in go/nogo task. I. Topographical characteristics to different visual stimulus sequences].

Event-related potentials (ERPs) were measured in eight healthy right-handed adults during three different visual Go/NoGo tasks, which consisted of color, figure, and Chinese character (kanji) paradigms. Subjects responded to a Go stimulus after a cue stimulus from the monitor during the execution of a continuous performance test (CPT). We obtained ERPs of the Go and NoGo conditions from 13-channel EEG recordings and measured peak latency, amplitude, and topographic distribution of each component. The N2 components of the figure and kanji NoGo tasks were located from Fz to Cz;o n the other hand, the N2 distribution of the color task was significant from Cz to Pz. The P3 component of both the Go and NoGo tasks were mostly seen from Cz to Pz. The NoGo-P3 components were distributed in more anterior regions than Go-P3 topography. In the color task, the amplitude of NoGo P3 was highest and the latency was shortest of the three tasks. These results suggest that ERP components in visual Go/NoGo tasks are most distinguishable in the color task.,and that NoGo potentials in a color task might be a useful tool for cognitive testing in children.

[Event-related potentials to response production and inhibition in go/nogo task. II. Developmental change of response inhibition].

In order to investigate the developmental changes of response inhibition in frontal function, event related potentials (ERPs) during a Go/NoGo task were collected. Twelve developmentally normal subjects, ranging in age from 7 to 15, and 9 normal adults performed a visual Go/NoGo task, which is a continuous performance test (CPT) using 5 color samples. We obtained ERPs of the Go and NoGo conditions from 13-channel EEG recordings and measured peak latency, amplitude, and topographic distribution of the NoGo N2 and NoGo P3 components. The NoGo N2 components were located at Fz in childhood, but changed from Cz to Pz in adulthood. The NoGo N2 amplitude diminished linearly with age. The NoGo P3 components were significant at Cz at all ages and the amplitude increased with age. The pattern of NoGo N2 and NoGo P3 components in 7-to 15-year-old children were similar, but differed in adults. These results suggest that the maturation of response inhibition in frontal lobe is achieved beyond 15 years of age, and that NoGo 3 amplitude particularly reflects the maturation of response inhibition.