title: Neurophysiological investigations in patients with primary writing tremor.
abstract: The pathophysiology of primary writing tremor (PWT) is still unknown: it has been classified as a focal form of essential tremor and as a tremulous form of writer's cramp. We studied cortical and spinal excitability in patients with PWT and compared the results with published data of patients with essential tremor, and writer's cramp. We used electrical stimulation of median and radial nerve to study reciprocal inhibition of forearm antagonist muscles and paired transcranial magnetic stimulation at short and long interstimulus intervals (ISIs) to assess intracortical excitability. Both studies were conducted on patients with PWT and on control subjects. The early (presynaptic) and late (disynaptic) phases of reciprocal inhibition were normal as was intracortical excitability at short and long ISIs. Our study suggests that the pathophysiology of PWT is different from that of writer's cramp and partially also from that of essential tremor.
authors.affiliation: Dipartimento di Scienze Neurologiche, Universitá di Roma La Sapienza, Roma, and Istituto Neurologico Mediterraneo Neuromed, Pozzilli, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Modugno
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Sven
authors.initials: S
authors.lastname: Bestmann
authors.forename: Antonio
authors.initials: A
authors.lastname: Curra
authors.forename: Alfredo
authors.initials: A
authors.lastname: Berardelli
authors.forename: John
authors.initials: J
authors.lastname: Rothwell
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology; D020821:Dystonic Disorders / Q000175:diagnosis* / Q000503:physiopathology; D004576:Electromyography; D020329:Essential Tremor / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006181:H-Reflex / Q000502:physiology; D006236:Handwriting; D006801:Humans; D008280:Magnetics; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation; D009433:Neural Inhibition / Q000502:physiology; D011826:Radial Nerve / Q000503:physiopathology; D009435:Synaptic Transmission / Q000502:physiology; D013614:Tachycardia, Paroxysmal; D014202:Tremor / Q000175:diagnosis* / Q000503:physiopathology