Cerebellar contributions to the processing of saccadic errors.

Saccades are fast eye movements that direct the point of regard to a target in the visual field. Repeated post-saccadic visual errors can induce modifications of the amplitude of these saccades, a process known as saccadic adaptation. Two experiments using the same paradigm were performed to study the involvement of the cerebrum and the cerebellum in the processing of saccadic errors using functional magnetic resonance imaging and in-scanner eye movement recordings. In the first active condition, saccadic adaptation was prevented using a condition in which the saccadic target was shifted to a variable position during the saccade towards it. This condition induced random saccadic errors as opposed to the second active condition in which the saccadic target was not shifted. In the baseline condition, subjects looked at a stationary dot. Both active conditions compared with baseline evoked activation in the expected saccade-related regions using a stringent statistical threshold [the frontal and parietal eye fields, primary visual area, MT/V5, and the precuneus (V6) in the cerebrum; vermis VI-VII; and lobule VI in the cerebellum, known as the oculomotor vermis). In the direct comparison between the two active conditions, significantly more cerebellar activation (vermis VIII, lobules VIII-X, left lobule VIIb) was observed with random saccadic errors (using a more relaxed statistical threshold). These results suggest a possible role for areas outside the oculomotor vermis of the cerebellum in the processing of saccadic errors. Future studies of these areas with, e.g., electrophysiological recordings, may reveal the nature of the error signals that drive the amplitude modification of saccadic eye movements.

Course of tricuspid atresia in the Fontan era.

Tricuspid atresia is an uncommon form of congenital heart disease and long-term survival was rare before the Fontan era. It was thought that the long-term survival of patients with tricuspid atresia would be improved by the introduction of the Fontan procedure and its subsequent modifications. This study reviews the clinical course of 84 patients with tricuspid atresia identified in the first year of life in the Fontan era. Prior palliative operations, their results and their ultimate application for the Fontan procedure were considered. Eleven patients died before surgical intervention and 5 did not undergo catheterization or echocardiographic confirmation before death. Five children underwent the Fontan procedure without prior palliation and 1 child does not require palliation at the present time. Sixty-seven patients (80%) had surgical procedures before evaluation for the suitability of a Fontan operation. Thirty-four patients had a second surgical palliation and 9 patients had a third palliation. The surgical mortalities for the first, second and third palliative surgery were 17.9, 17.6 and 0%, respectively. Thirty-two patients (38%) underwent the Fontan procedure and 2 deaths occurred (6%). An estimate of the probability of surviving for 1 year was 64% (95% confidence limits 54 to 74%) and that of 8 years was 55% (95% confidence limits 44 to 66%).

Bilateral ankylosis of temporomandibular joint secondary to ankylosing spondylitis in a male Chinese.

A case of bilateral temporomandibular joint (TMJ) ankylosis in a Chinese male patient with ankylosing spondylitis is presented. A review of the literature emphasizes the rarity of this arthro-pathology in ankylosing spondylitis. The importance in the recognition of this complication by clinical examination supplemented by computed tomography is stressed.