CONSIDERABLE interest has been focused on the entity of progressive external ophthalmoplegia (PEO) since the report of Kiloh and Nevin in 1951.1 These authors were primarily concerned with the pathogenesis of the ocular muscle weakness, concluding that it was virtually always the result of a myopathic process. They regarded PEO as a distinctive and relatively isolated disorder, although occasionally associated with mild myopathy elsewhere; they considered its association with other neurodegenerative findings to be "extremely rare," citing only the cases of Marburg2 and of Walsh.3 More recently, however, PEO has been linked with a variety of neurologic abnormalities in increasing numbers of reports. In addition to myopathic involvement of limb musculature, other neurologic symptoms including pharyngeal weakness, peripheral neuropathy, cerebellar ataxia, spasticity, deafness, optic atrophy, and dementia have been observed in conjunction with PEO. Other organ systems also involved have included the heart, endocrine glands, skin, bony skeleton, and eye.Based on the various combinations of clin¬ ical signs and laboratory findings, a number of "new syndromes" have been described in which PEO occurs as a constant or variable feature. New reports of older, well-known syndromes have also shown that PEO may occur in association with disorders long re¬ garded as cerebellar or neuropathic degener¬ ative conditions. Because of the overlap of clinical and laboratory findings among these conditions, the separation and classification of degenerative disorders in which PEO oc¬ curs has become deeply entangled; the con¬ ditions reported as new syndromes by one author are "variants" or "formes frustes" of a different syndrome to another author. Add¬ ing to the confusion has been an underlying concern for the purity of distinction between myopathie and neurodegenerative disorders.We have recently studied four unrelated patients in whom PEO occurred in combina¬ tion with extensive involvement of the nerv¬ ous system and other organs. Certain of the clinical and laboratory findings were closely similar; others differed. The concordant and discordant features provided an illuminating example of the difficulty of basing a system of nosology primarily on the semiology (symptoms and signs) of these degenerative conditions.The purpose of this report is to note the findings in these cases of "ophthalmoplegia plus"; to call attention to the range of ab¬ normalities that have been reported in asso¬ ciation with PEO; and, in light of these findings, to review and evaluate the classifi¬ cation of related degenerative disorders.
Report of CasesCase 1.-History.-A 16-year-old girl was seen because of ocular motor weakness and un¬ steadiness of gait. She had been entirely well until age 8, when she was noted to have droop¬ ing of the eyelids and limitation of gaze in all directions. Within two years she developed difficulty in swallowing, faintness of the voice, and a hearing loss. In school she was consid¬ ered below average intellectually. At age...