Utako Takechi1, Kaoru Matsunaga2, Ryoji Nakanishi2, Hiroaki Yamanaga2, Nobuki Murayama3, Kosuke Mafune4, Sadatoshi Tsuji5. 1. Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan. Electronic address: Utako@med.uoeh-u.ac.jp. 2. Department of Neurology and Rehabilitation Medicine, Kumamoto Kinoh Hospital, Kumamoto, Japan. 3. Department of Human and Environmental Informatics, Graduate School of Science and Technology, Kumamoto University, Japan. 4. Department of Mental Health, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Japan. 5. Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Japan.
Abstract
OBJECTIVE: A general lack of longitudinal studies on interhemispheric interactions following stroke led us to use transcranial magnetic stimulation (TMS) to examine changes in corticospinal/intracortical excitability and transcallosal inhibition over a 1-year period following subcortical stroke. METHODS: We measured TMS parameters such as motor threshold (MT), short-interval intracortical inhibition (SICI), and ipsilateral silent period (iSP) and evaluated clinical scores at three time-points (T1, T2, and T3) in 24 patients and 25 age-matched healthy subjects. RESULTS: At T1, we observed reduced MTs and SICIs with prolonged iSPs in the unaffected hemisphere (UH). In contrast, increased MTs and reduced SICIs were observed in the affected hemisphere (AH). These abnormalities gradually reduced and no MEP response to TMS at T1 predicted a worse prognosis. The prolonged iSP at T1 was associated with more severe impairments, but it did not necessarily predict a worse prognosis after 1year. CONCLUSIONS: UH excitability was increased at the post-acute time-period, which may have resulted in enhanced transcallosal inhibition to the AH. However, it is unclear whether there was a causal relationship between the enhanced transcallosal inhibition and the extent of clinical recovery. SIGNIFICANCE: This is the first study to demonstrate changes in transcallosal inhibition over a longitudinal period following stroke.
OBJECTIVE: A general lack of longitudinal studies on interhemispheric interactions following stroke led us to use transcranial magnetic stimulation (TMS) to examine changes in corticospinal/intracortical excitability and transcallosal inhibition over a 1-year period following subcortical stroke. METHODS: We measured TMS parameters such as motor threshold (MT), short-interval intracortical inhibition (SICI), and ipsilateral silent period (iSP) and evaluated clinical scores at three time-points (T1, T2, and T3) in 24 patients and 25 age-matched healthy subjects. RESULTS: At T1, we observed reduced MTs and SICIs with prolonged iSPs in the unaffected hemisphere (UH). In contrast, increased MTs and reduced SICIs were observed in the affected hemisphere (AH). These abnormalities gradually reduced and no MEP response to TMS at T1 predicted a worse prognosis. The prolonged iSP at T1 was associated with more severe impairments, but it did not necessarily predict a worse prognosis after 1year. CONCLUSIONS: UH excitability was increased at the post-acute time-period, which may have resulted in enhanced transcallosal inhibition to the AH. However, it is unclear whether there was a causal relationship between the enhanced transcallosal inhibition and the extent of clinical recovery. SIGNIFICANCE: This is the first study to demonstrate changes in transcallosal inhibition over a longitudinal period following stroke.
Authors: Jacqueline A Palmer; Lewis A Wheaton; Whitney A Gray; Mary Alice Saltão da Silva; Steven L Wolf; Michael R Borich Journal: Neurorehabil Neural Repair Date: 2019-07-22 Impact factor: 3.919
Authors: Whitney A Gray; Jacqueline A Palmer; Steven L Wolf; Michael R Borich Journal: Neurorehabil Neural Repair Date: 2017-06-12 Impact factor: 3.919