Frequency-velocity mismatch: a fundamental abnormality in parkinsonian gait
Cho, Catherine; Kunin, Mikhail; Kudo, Koji; Osaki, Yasuhiro; Olanow, C Warren; Cohen, Bernard; Raphan, Theodore
Gait dysfunction and falling are major sources of disability for patients with advanced Parkinson's disease (PD). It is presently thought that the fundamental defect is an inability to generate normal stride length. Our data suggest, however, that the basic problem in PD gait is an impaired ability to match step frequency to walking velocity. In this study, foot movements of PD and normal subjects were monitored with an OPTOTRAK motion-detection system while they walked on a treadmill at different velocities. PD subjects were also paced with auditory stimuli at different frequencies. PD gait was characterized by step frequencies that were faster and stride lengths that were shorter than those of normal controls. At low walking velocities, PD stepping had a reduced or absent terminal toe lift, which truncated swing phases, producing shortened steps. Auditory pacing was not able to normalize step frequency at these lower velocities. Peak forward toe velocities increased with walking velocity and PD subjects could initiate appropriate foot dynamics during initial phases of the swing. They could not control the foot appropriately in terminal phases, however. Increased treadmill velocity, which matched the natural PD step frequency, generated a second toe lift, normalizing step size. Levodopa increased the bandwidth of step frequencies, but was not as effective as increases in walking velocity in normalizing gait. We postulate that the inability to control step frequency and adjust swing phase dynamics to slower walking velocities are major causes for the gait impairment in PD.
PMCID:2887635
PMID: 20042701
ISSN: 1522-1598
CID: 1860042
Atypical speech abnormality following initiation of deep brain stimulation of the subthalamic nucleus (STN-DBS) for Parkinson's disease (PD) [Meeting Abstract]
Gupta, F; Cho, C; Sidtis, D; Sidtis, JJ; Alterman, RL; Tagliati, M
ISI:000266618101633
ISSN: 0885-3185
CID: 2243682
A model-based approach for assessing Parkinsonian gait and effects of levodopa and deep brain stimulation [Meeting Abstract]
Cho, Catherine; Osaki, Yasuhiro; Kunin, Mikhail; Cohen, Bernard; Olanow, C. Warren; Raphan, Theodore
ISI:000247284705212
ISSN: 1557-170x
CID: 4590612
A lesion of the anterior thalamus producing dystonic tremor of the hand [Case Report]
Cho, C; Samkoff, L M
BACKGROUND: Thalamic tremor is typically characterized by resting and intention components; a postural element is often present as well. Previously reported cases of acquired thalamic tremor have demonstrated lesions in the posterior thalamus or dentatorubrothalamic tract. OBJECTIVES: To report a case of dystonic-postural tremor of the upper extremity that occurred after a contralateral anterior thalamic infarct, and to discuss potential tremorigenic mechanisms. DESIGN: Case report. SETTING: Municipal hospital neurology clinic. PATIENT: A 65-year-old right-handed woman suddenly developed a dystonic tremor in her left hand after undergoing coronary bypass surgery. The tremor persisted unchanged for 8 months, at which time she was evaluated by us. Cranial magnetic resonance imaging scans demonstrated a right anterior thalamic infarct. CONCLUSION: To our knowledge, this is the first report of focal tremor caused by a lesion of the anterior thalamus.
PMID: 10987904
ISSN: 0003-9942
CID: 613772