It has long been known that the oculomotor system is not involved in a
myotrophic lateral sclerosis (ALS). In early stages. Some authors sugg
est oculomotor abnormalities in some patients. In the present study, q
uantitative analysis of ocular movements including smooth pursuit eye
movements, optokinetic nystagmus (OKN), visual suppression of vestibul
ar nystagmus (VS), and horizontal saccades were investigated in 9 pati
ents with ALS. These patients were neurologically diagnosed as having
ALS in the early stage. The results were as follows; The velocity of s
accade was markedly reduced in 4 patients. In addition, there were abn
ormalities of smooth pursuit (one patient), OKN (one patient) and visu
al suppression (2 patients). Furthermore, these abnormalities were obs
erved more often in patients with bulbar signs, In conclusion, the res
ults suggest a existence of ocular abnormalities in ALS, even at early
stages.