[Analysis of gait disturbance in a patient with corticobasal degeneration]

A 64-year-old right-handed man was admitted because of increasing clumsiness of the right hand and difficulty in walking since 8 months earlier. The WAIS revealed verbal IQ 124, performance IQ 104 and full scale IQ 115. Neurological examination revealed slight dysarthria and normal eye movements. The right upper extremity showed Gegenhalten, tremor, dystonic elbow flexion, marked grasp reflex, grasping and groping behavior. Voluntary movements were slow and clumsy on the right side. However, neither ideational nor ideomotor apraxia was observed. Tendon reflexes were slightly exaggerated on the right side. Plantar responses were normal. The patient had difficulty in initiating forward walking and turning movements. Once started, he walked dragging his right foot ahead of the left with short steps. A line on the floor was of no benefit. He could not stride across the line on the floor in front of him. Analysis of gait with floor reaction force revealed that the single step rhythm of his frozen gait was about 1.5 Hz, which contrasted with the high frequency seen in Parkinson's disease. MRI demonstrated atrophy of the frontal and parietal lobes on both sides. 123I-IMP single-photon emission CT demonstrated severe hypoperfusion of the left frontal and parietal lobes. Frozen or shuffling gait is a popular symptom as well as unsteady gait and tendency to fall in corticobasal degeneration. It may result from the frontal lobe dysfunction. Lack of improvement in freezing by the visual input contrasts with Parkinson's disease and may be related to dysfunction of the mesial part of the frontal lobe or the parietal lobe involved in corticobasal degeneration.