title: Temporary deafferentation evoked by cutaneous anesthesia: behavioral and electrophysiological findings in healthy subjects.
abstract: Motor function and motor excitability can be modulated by changes of somatosensory input. Here, we performed a randomized single-blind trial to investigate behavioral and neurophysiological changes during temporary deafferentation of left upper arm and forearm in 31 right-handed healthy adults. Lidocaine cream was used to anesthetize the skin from wrist to shoulder, sparing the hand. As control condition, on a different day, a neutral cream was applied to the same skin area. The sequence (first Lidocaine, then placebo or vice versa) was randomized. Behavioral measures included the Grating Orientation Task, the Von Frey hair testing and the Nine-hole-peg-test. Transcranial magnetic stimulation was used to investigate short-interval intracortical inhibition, stimulus response curves, motor evoked potential amplitudes during pre-innervation and the cortical silent period (CSP). Recordings were obtained from left first dorsal interosseous muscle and from left flexor carpi radialis muscle. During deafferentation, the threshold of touch measured at the forearm was significantly worse. Other behavioral treatment-related changes were not found. The CSP showed a significant interaction between treatment and time in first dorsal interosseous muscle. CSP duration was longer during Lidocaine application and shorter during placebo exposure. We conclude that, in healthy subjects, temporary cutaneous deafferentation of upper and lower arm may have minor effects on motor inhibition, but not on sensory or motor function for the adjacent non-anesthetized hand.
authors.affiliation: Kliniken Schmieder Allensbach, Lurija Institut, Zum Tafelholz 8, 78476, Allensbach, Germany. aida.sehle@uni-konstanz.de.
authors.forename: Aida
authors.initials: A
authors.lastname: Sehle
authors.affiliation: Kliniken Schmieder Allensbach, Lurija Institut, Zum Tafelholz 8, 78476, Allensbach, Germany.
authors.forename: Imke
authors.initials: I
authors.lastname: Büsching
authors.affiliation: Kliniken Schmieder Allensbach, Lurija Institut, Zum Tafelholz 8, 78476, Allensbach, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Vogt
authors.affiliation: Kliniken Schmieder Allensbach, Lurija Institut, Zum Tafelholz 8, 78476, Allensbach, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Liepert
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology; D055592:Biophysical Phenomena / Q000187:drug effects; D013181:Cortical Spreading Depression / Q000187:drug effects; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D005260:Female; D005542:Forearm / Q000294:innervation*; D064368:Healthy Volunteers; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal; D009949:Orientation / Q000187:drug effects; D012684:Sensory Thresholds / Q000187:drug effects; D016037:Single-Blind Method; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: Cutaneous de-afferentation; Lidocaine cream; Motor excitability; Sensorimotor function; Transcranial magnetic stimulation