HEREDITARY ATAXIA In the year 1S6I the Heidelberg clinician, Friedreich, described a symptom-complex which occurs in members of the same family, and is charactoized by onset during childhood, ataxia, absence of the patellar reflex, nystaginus, pcs equinus, and a slowly progressive course. Schultze later had an opportunity uf examining a case post mortem and found changes in the posterior colunms of the spinal cord which he regarded as the pathologic foundation of the disease. The existence of this clinical picture has since been confirmed by an extraordinary number of publications: a Frenchman (Brousse) gave it the name of Friedreieh's disease. Gradually, however, it was found that the disease was less sharply defined than it had at first been supposed. It was observed in older individuals; some of the charactoistic symptoms were found to be absent, and finally, post-mortem exantination of a fen- cases revealed other disturbances of the central nervous system such as de generation of the pyramidal tracts and changes in the cerebellum. After Senator had been lecl by the pathologic findings to question our original conception of the disease, Marie came forward with the de scription of a morbid condition which, along with many points of re semblance to Frieclreich's disease, exhibited so many peculiar features that he deemed it necessary to regard it as an independent nosologic entity. Clinically this condition differed from Friedreich's disease by its onset at a later period of life (after the age of 20), greater uncer tainty in the gait (cerebellar gait), the fact that tendon reflexes were present or exaggerated, ocular palsies and, occasionally, atrophy of the optic nerve. Post mortem, hypoplasia of the cerebellum with secondary degenerations were found. Marie gave it the name of hertitloataxie cerebelleuse. The existence of this disease was also soon confirmed by numerous cases reported in tlw literature (Londe's collection). It seemed as if a distinct. advance had been made in the differentiation of the individual forms of hereditary ataxia, but this distinction also was found to be untenable. Cases were soon discovered which combined symptoms of both diseases. Then came the reports of autopsies with simultaneous changes in the cerebellum and in the spinal cord, and others with atrophy of the cerebellum but without cerebellar symptoms. In
view of these facts most authors (first of all Londe, then Bflundin, Seiner, Veraguth, Oppenheim, _Raymond and quite recently Nonne and others) have expressed the opinion that Friedreich's tabes and her6 doataxie cerebelleuse can no longer be distinguished either clinically or pathologically and that it is more correct to include all these condi tions under the head of hereditary ataxia, with preponderance of the spinal symptoms in some cases and of the cerebellar symptoms in others. Between ataxic diseases and other forms of endogenous diseases even the dividing line has been shifted since Baumlin ancl others described cases of Friedreich's clisease associated with muscular changes.
Hereditary ataxia is a distinctly hereditary disease and has been observed in two or three SIICCOSSIVe generations. As a rule either the male members or the female members of a family are exclusively at tacked, but there appears to be no difference between the sexes as re gards frequency. Isolated cases of the disease are not rare and are usually of the spinal form; the fact that single eases are frequently observed in France has been explained with some apparent reason by Socas as due to the small number of children in that country. Whether in this form of hereditary disease consanguinity and alcoholism in the parents, infectious diseases and traumatism play an important part is doubtful and indeed very unlikely as regards the last two factors. Edinger's theory, so far as it applies in Friedreich's talws, has been exhaustively discussed by Bing.
In the spinal form the onset of an hereditary ataxia occurs in child hood usually between the ages of four and seven (11fitimeyer's case in a _child two years old, Seiner). Vizioli's analysis gives the onset during the first decade of life in 39 out of 60 eases, but exceptions also occur in which the disease begins at a later period. In cerebellar ataxia the first symptoms, according to Marie and others, appear during the twenties and according to other authors at a still later age; but there are also cases of Friedreich's ataxia with very early onset (Fraser, Baumlin and my case in a child three and a half years old). It appears therefore that there is no constant difference between spinal and cere bellar forms of ataxia as regards the age when the disease first makes its appearance.