M Cortes1,2,3, G W Thickbroom1,4, J Elder5, A Rykman1, J Valls-Sole3, A Pascual-Leone6,7, D J Edwards1,2,6. 1. Non-invasive Brain Stimulation and Human Motor Control Laboratory, Burke Medical Research Institute, White Plains, NY, USA. 2. Department of Neurology, Cornell University, New York, NY, USA. 3. EMG and Motor Control Unit, Neurology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain. 4. Department of Rehabilitation Medicine, Cornell University, New York, NY, USA. 5. Department of Epidemiology, Cornell University, New York, NY, USA. 6. Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. 7. Institut Universitari de Neurorehabilitacio Guttmann, Department of Neurology, Universitat Autonoma, Barcelona, Spain.
Abstract
STUDY DESIGN: A cross-sectional study in chronic spinal cord injury with cervical lesions (cSCI). OBJECTIVE: To determine the corticomotor projection and motor cortex organization of paralyzed forearm muscles that presented only liminal voluntary activation. SETTING: Burke Medical Research Institute, White Plains, NY, USA. METHODS: We identified ten people with chronic SCI who had a wrist flexor or extensor muscle with a motor power (MP) of 1 over 5. We recorded motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) over the primary motor cortex of the hemisphere contralateral to the target muscle. We measured resting motor threshold (RMT), corticomotor latency (LTY), MEP amplitude (AMP) and performed cortical motor mapping to determine the optimal site (OPT) and map area (AREA). Results were compared with the data from 18 controls. RESULTS: A MEP in the target muscle was observed for all cSCI cases. LTY was normal, while corticomotor excitability (as determined by RMT and AMP) was reduced in about half of the group. The OPT site of the motor maps was within control range for all cSCI cases, while AREA was reduced in three cases. CONCLUSIONS: Corticomotor conduction and cortical topography were appreciably normal despite only liminal activation of the target muscle with voluntary effort. Muscles with these characteristics may benefit from a targeted rehabilitation program even in the chronic phase after SCI.
STUDY DESIGN: A cross-sectional study in chronic spinal cord injury with cervical lesions (cSCI). OBJECTIVE: To determine the corticomotor projection and motor cortex organization of paralyzed forearm muscles that presented only liminal voluntary activation. SETTING: Burke Medical Research Institute, White Plains, NY, USA. METHODS: We identified ten people with chronic SCI who had a wrist flexor or extensor muscle with a motor power (MP) of 1 over 5. We recorded motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) over the primary motor cortex of the hemisphere contralateral to the target muscle. We measured resting motor threshold (RMT), corticomotor latency (LTY), MEP amplitude (AMP) and performed cortical motor mapping to determine the optimal site (OPT) and map area (AREA). Results were compared with the data from 18 controls. RESULTS: A MEP in the target muscle was observed for all cSCI cases. LTY was normal, while corticomotor excitability (as determined by RMT and AMP) was reduced in about half of the group. The OPT site of the motor maps was within control range for all cSCI cases, while AREA was reduced in three cases. CONCLUSIONS: Corticomotor conduction and cortical topography were appreciably normal despite only liminal activation of the target muscle with voluntary effort. Muscles with these characteristics may benefit from a targeted rehabilitation program even in the chronic phase after SCI.
Authors: J D Steeves; D Lammertse; A Curt; J W Fawcett; M H Tuszynski; J F Ditunno; P H Ellaway; M G Fehlings; J D Guest; N Kleitman; P F Bartlett; A R Blight; V Dietz; B H Dobkin; R Grossman; D Short; M Nakamura; W P Coleman; M Gaviria; A Privat Journal: Spinal Cord Date: 2006-12-19 Impact factor: 2.772
Authors: Syed Faraz Kazim; Christian A Bowers; Chad D Cole; Samantha Varela; Zafar Karimov; Erick Martinez; Jonathan V Ogulnick; Meic H Schmidt Journal: Mol Neurobiol Date: 2021-08-03 Impact factor: 5.590