James Sharpe's Contributions to Neurology and Neuro-ophthalmology: A Posthumous Tribute 10 Years On.

Dr. Sharpe was a leading eye movement researcher who had also been the editor of this journal. We wish to mark the 10th anniversary of his death by providing a sense of what he had achieved through some examples of his research.

Mitochondrial pseudomyasthenia.

The classic ocular motor presentation of mitochondrial disorders is chronic, symmetric, and diffuse weakness. We describe a man with 25 years of asymmetric ptosis, ophthalmoparesis, and facial weakness that partially responded to steroid therapy. Serologic and electrophysiological investigations for myasthenia gravis were negative, but muscle biopsy confirmed a mitochondrial myopathy. This case illustrates the potential of mitochondrial ophthalmoparesis to mimic the features of ocular myasthenia.

My, what asthenia you have.

A 59-year-old woman noted intermittent ptosis, diplopia, dysphagia, and proximal muscle weakness for several years. She had a strong family history of myasthenia gravis. Chest computed tomography and sternotomy revealed a micronodular spindle cell thymoma. Electromyography and antibody testing was negative for myasthenia gravis. Genetic testing confirmed a diagnosis of oculopharyngeal muscular dystrophy.

Scan patterns during the processing of facial identity in prosopagnosia.

The scan patterns of ocular fixations made by prosopagnosic patients while they attempt to identify faces may provide insights into how they process the information in faces. Contrasts between their scanning of upright versus inverted faces may index the presence of a hypothesized orientation-dependent expert mechanism for processing faces, while contrasts between their scanning of familiar versus novel faces may index the influence of residual facial memories on their search for meaningful facial information. We recorded the eye movements of two prosopagnosics while they viewed faces. One patient, with acquired prosopagnosia from a right occipitotemporal lesion, showed degraded orientation effects but still with a normal distribution of fixations to more salient facial features. However, the dynamics of his global scan patterns were more chaotic for novel faces, suggesting degradation of an internal facial schema, and consistent with other evidence of impaired face configuration perception in this patient. His global scan patterns for famous faces differed from novel faces, suggesting the influence of residual facial memories, as indexed previously by his relatively good imagery for famous faces. The other patient, with a developmental prosopagnosia, showed anomalous orientation effects, abnormal distribution of fixations to less salient regions, and chaotic global scan patterns, in keeping with a more severe loss of face-expert mechanisms. The effects of fame on her scanning were weaker than those in the first subject and non-existent in her global scan patterns. We conclude that scan patterns in prosopagnosia can both reflect the loss of orientation-dependent expert mechanisms and index the covert influence of residual facial memories. In these two subjects the scanning data were consistent with other results from tests of configuration perception, imagery, and covert recognition.