Prevalence and clinical characteristics of corticobasal syndrome with an initial symptom outside of the upper limb.

Although typical corticobasal syndrome (CBS) presents with asymmetric upper limb symptoms, the prevalence and clinical characteristics of patients with symptoms beginning in other sites are unknown. From January 1997 through April 2016, consecutive patients with CBS who fulfilled the modified Cambridge criteria were recruited. Their medical records were reviewed to determine the body part, where the initial symptoms developed and the clinical characteristics. A total of 24 patients [13 female participants, median age at onset: 64 (IQR 60-74) years, and median duration between onset and evaluation: 38 (17-53) months] met the criteria. The initial symptom involved the unilateral upper limb in 14 cases (58%), unilateral lower limb in five (21%), gait in four (17%), and visual field in one (4%). Over a median of 59 (IQR 40-68) months of follow-up, the duration between the onset and the time for need of assistance in walking was significantly shorter in the patients with lower limb (p = 0.018 with log-rank test) or gait (p = 0.025) onset than in those with upper limb onset. About a half of the CBS patients initially complained of symptoms other than the upper limb. The most common area of origin of the initial symptom after the upper limb was the lower limb followed by gait. Such patients need assistance in walking earlier than those with upper limb-onset CBS. Patients with lower limb- or gait-onset CBS are not rare and may have unfavorable outcome.