Developmental dyslexia. Evidence for a subgroup with a reversal of cerebral asymmetry.

The computerized brain tomograms of 24 patients with developmental dyslexia were analyzed for cerebral asymmetry. Ten patients showed a reversal of the pattern of asymmetry regularly observed in normal right-handed individuals so that the right parietooccipital region was wider than the left. The ten dyslexic patients with this reversal of cerebral asymmetry had a lower mean verbal IQ than the other 14 dyslexic patients in this study. The reversal of cerebral asymmetry that occurred in ten of the dyslexic patients may result in language lateralization to a cerebral hemisphere that is structurally less suited to support language function and thus act as a risk factor for the development of reading disability.

Horner syndrome with causalgia.

A previously healthy man presented with burning pain in the chest wall and arm; there was Horner syndrome on the same side. After extensive investigation, the disorder was attributed to a foraminal osteophyte involving the left T1 spinal root.

The thymus gland in elderly patients with myasthenia gravis.

This study was undertaken to determine the amount and histologic appearance of the persistent thymic tissue removed post mortem from 20 patients over 60 years of age with myasthenia gravis. One patient died several days after thymectomy. No recognizable thymic tissue on gross examination was seen in any patient. On microscopic examination, 11 patients had no thymic tissue. The other nine patients, including the one with thymectomy, all showed marked involution of the thymus. No germinal centers were seen. The thymus glands of two additional patients, still alive after thymectomy at ages 62 and 70, showed similar findings. Marked involution of the thymus also was found in each of six elderly controls. Thymectomy is not likely to be effective treatment of the elderly myasthenic patient.

Effect of prethymectomy plasma exchange on postoperative respiratory function in myasthenia gravis.

The effect of prethymectomy plasma exchange on postoperative mechanical ventilation requirement and length of stay in the intensive care unit were studied retrospectively in 37 patients with myasthenia gravis. We found a significantly decreased time on mechanical ventilation (mean 1.02 +/- 0.40 versus 3.43 +/- 0.60 days) and a shorter stay in the intensive care unit (mean 3.09 +/- 0.99 versus 5.15 +/- 0.66 days) for 11 patients with respiratory weakness who were treated with preoperative plasma exchange compared with 26 patients who did not receive plasma exchange. Patients with respiratory weakness who received prethymectomy plasma exchange required less time on mechanical ventilation (mean 1.02 +/- 0.40 versus 2.73 +/- 0.88 days) and a shorter stay in the intensive care unit (mean 3.09 +/- 0.99 versus 4.46 +/- 1.08 days) than those patients without respiratory weakness who did not receive plasma exchange. Eleven patients met the criteria for plasma exchange but did not receive it. They required significantly more time on mechanical ventilation (mean 4.43 +/- 0.94 versus 1.02 +/- 0.40 days) and in the intensive care unit (mean 6.09 +/- 0.86 versus 3.09 +/- 0.99 days) than patients who received plasma exchange. Our results indicate that patients with severe forms of myasthenia gravis treated with prethymectomy plasma exchange require less mechanical ventilation and less time in the intensive care unit postoperatively.

Learning disorders and sex chromosome aberrations.

No sex chromosome aberrations were detected in a prospective study of twenty adult dyslexic men. A retrospective study of eighty-nine subjects with known sex chromosome aberrations revealed twenty of them to be mentally-retarded. Among the sixty-nine subjects of normal intelligence, learning, speech and attention disorders were frequent. Children with 47,XYY, 47,XXY, and 47,XXX karyotypes appeared particularly prone to experience delays in speech development as well as later academic underachievement in language-related subjects. In contrast, speech development was normal in all of the girls with Turner's syndrome and later academic difficulties were usually confined to mathematics or science. Hyperactivity was noted with considerable frequency among 47,XYY and Turner's syndrome subjects, but not among subjects with a 47,XXX or 47,XXY karyotype.