Patients with adult-onset Krabbe disease can develop slowly progressive spastic paraplegia. However, few neurophysiological studies in the central nervous system have been reported. Here, we investigated central motor and sensory conduction in a patient with mild adult-onset Krabbe disease.

cortical excitability. Both OPS and QPS induced sustained bidirectional excitability changes of M1 depending on the stimulation frequency as compared with sham stimulation. Moreover, the duration of aftereffects was longer after OPS compared to QPS. In conclusion, OPS and QPS induce powerful bidirectional plasticity of M1. The number of stimuli within one burst may be of particular importance for the duration of the induced plasticity.

Crowned dens syndrome（CDS）は軸椎歯突起周囲の靭帯にピロリン酸カルシウム結晶が沈着し，発熱，頸部痛，炎症所見を示す急性関節炎で，高齢女性に好発する偽痛風の一型である．2症例は72歳女性と31歳女性，いずれも頸部痛，炎症反応の上昇を伴った．頸椎単純CTとその再構成画像で歯突起周囲靭帯の石灰化を認めCDSと診断．非ステロイド性抗炎症薬投与により，自覚症状と炎症所見の消失をみた．炎症所見を伴う頸部痛では本疾患を念頭におき，CTで石灰化の有無を検討する必要がある．

This report describes a 60-year-old female patient with Krabbe disease who presented with slowly progressive gait disturbance due to mild spastic paraplegia. Brain magnetic resonance imaging showed high-intensity lesions along the upper parts of the bilateral pyramidal tracts in fluid-attenuated inversion recovery images. Central motor conduction time was prolonged both in the upper and the lower extremities, while central sensory conduction time was normal. The reduced lymphocyte galactocerebrosidase (GALC) activity and two novel mutations in the GALC gene, p.G496S and p.G569S, proved the diagnosis of Krabbe disease. Our findings show that adult-onset Krabbe disease is characterized by isolated pyramidal tract impairment in the central nervous system, both neurophysiologically and radiologically.