Spinal myoclonus following a peripheral nerve injury: a case report

Spinal myoclonus is a rare disorder characterized by myoclonic movements in muscles that originate from several segments of the spinal cord and usually associated with laminectomy, spinal cord injury, post-operative, lumbosacral radiculopathy, spinal extradural block, myelopathy due to demyelination, cervical spondylosis and many other diseases. On rare occasions, it can originate from the peripheral nerve lesions and be mistaken for peripheral myoclonus. Careful history taking and electrophysiological evaluation is important in differential diagnosis

F-WAVE AND MOTOR-EVOKED POTENTIALS DURING MOTOR IMAGERY AND OBSERVATION IN APRAXIA OF PARKINSON DISEASE

Introduction: The amplitudes of F-waves and motor-evoked potentials (MEPs) increase during imagination or active motor performance. The aim of this study was to investigate F-wave and MEP facilitation during assessment of apraxia. Methods: Eight Parkinson disease (PD) patients with apraxia, 11 patients without apraxia, and 8 healthy volunteers were enrolled. F-waves and MEPs were recorded during 4 states (resting, imagination, observation, and active movement). Results: The mean amplitude of the F-waves increased significantly during imagination and active movement as compared with at rest in healthy individuals (P = 0.028) and in the nonapraxia group (P = 0.005). PD patients with apraxia did not have similar facilitation. The mean amplitude of the MEPs also showed a similar loss of facilitation in PD with apraxia. Conclusions: Loss of facilitation during the preparation for movement is closely related to the "gold standard" clinical praxis battery. This study provides additional support and a potential electrophysiological assessment method for apraxia in PD

Reorganization of sensory input at brainstem in hemifacial spasm and postparalytic facial syndrome

We hypothesized the filtering of sensory input from face and hand at brainstem may reorganize in hemifacial spasm (HFS) and postparalytic facial syndrome (PFS). Thus, we examined the prepulse inhibition of blink reflex (BR-PPI) in HFS and PFS. We included 12 healthy subjects, 13 patients with HFS, and 11 patients with PFS. Baseline BR, BR recovery at interstimulus interval (ISI) of 300 ms and BR-PPI at ISI of 100 ms were performed on the right sides of healthy subjects and on both sides of patients. Within-subject analysis showed baseline BR and BR-PPI were similar between asymptomatic and symptomatic sides of patients with HFS whereas BR recovery was higher on the symptomatic side. In the PFS group, latency of R2 during baseline BR recording was longer (p = 0.022) and R2 amplitude (p = 0.046) was reduced on the symptomatic side compared to asymptomatic side. Reduction of R2 area in BR-PPI recordings was also the lowest in HFS compared to other two groups (p = 0.000); however, it was also lower in patients with PFS compared to healthy subjects (p = 0.018). BR-PPI was decreased on both sides of patients. The mean R2 recovery was higher on both sides of patients with HFS and PFS (p = 0.007). Filtering of facial sensory input is decreased probably to monitor and to correct the sequence of facial movements in these disorders

Blink Reflex Studies in Postparalytic Facial Syndrome and Blepharospasm: Trigeminal and Extratrigeminal Somatosensory Stimulation

Purpose: The somatosensory-evoked blink reflex (SBR) is one of the release phenomena of blink reflex, possibly resulting from increased excitability of brainstem reticular formation

Dopaminergic medication unrelated myoclonus is less related to tremor in idiopathic Parkinson's disease

Myoclonus in Parkinson's disease (PD) may be related or unrelated to dopaminergic medication and may share some features of cortical myoclonus. The aim of this study was to analyze clinical and electrophysiological correlates of the dopaminergic treatment unrelated myoclonus in PD patients. We included 17 PD patients with the end-of-dose myoclonus and 16 PD patients without myoclonus between January 2010 and June 2011. Surface electromyography of upper extremity muscles and long latency reflexes (LLRs) were performed. Positive or negative myoclonus with a duration of 35-100 ms was observed. Rest tremor was less frequent in the group with myoclonus. Only one PD patient with myoclonus had C reflex. Mean LLR amplitude was significantly high in PD with myoclonus compared to the group without myoclonus (p = 0.024). Dopaminergic treatment unrelated myoclonus is less related to rest tremor in PD, may be positive or negative, and exhibits similar features to cortical myoclonus