Corticospinal excitability in patients with anoxic, traumatic, and non-traumatic diffuse brain injury

Abstract

Keywords:Brain injury Motor evoked potential Transcranial magnetic stimulation Short latency afferent inhibition a b s t r a c t Background: Transcranial magnetic stimulation (TMS) have been frequently used to explore changes in motor cortex excitability in stroke and traumatic brain injury, while the extent of motor cortex reorganization in patients with diffuse non-traumatic brain injury remains largely unknown. Objective/hypothesis: It was hypothesized that the motor cortex excitability would be decreased and would correlate to the severity of brain injury and level of functioning in patients with anoxic, traumatic, and non-traumatic diffuse brain injury. Methods: TMS was applied to primary motor cortices of 19 patients with brain injury (5 traumatic and 14 non-traumatic causes; on average four months after insult), and 9 healthy controls. The test parameters included resting motor threshold (RMT), short intracortical inhibition (SICI), intracortical facilitation (ICF), and short latency afferent inhibition (SAI). Excitability parameters were correlated to the severity of brain injury measured with Glasgow Coma Scale and the level of functioning assessed using the Ranchos Los Amigos Levels of Cognitive Functioning Assessment Scale and Functional Independence Measure. Results: The patient group revealed a significantly decreased SICI and SAI compared to healthy controls with the amount of SICI correlated significantly to the severity of brain injury. Other electrophysiological parameters did not differ between the groups and did not exhibit any significant relationship with clinical functional scores.Conclusions: The present study demonstrated the impairment of the cortical inhibitory circuits in patients with brain injury of traumatic and non-traumatic aetiology. Moreover, the significant correlation was found between the amount of SICI and the severity of brain injury.

Abnormal Corticospinal Excitability in Patients with Disorders of Consciousness

“…Reduced ICI and SAI was found in awake patients with anoxic, traumatic, and non-traumatic diffuse brain injury [46]. Moreover, the significant correlation was found between the amount of ICI and the severity of brain injury, while no correlation was found between motor cortex excitability parameters and patient functional level [46]. Both ICI and ICF impairment was found in five VS patients [47].…”

“…The other motor cortex excitability phenomena (e.g., short intracortical inhibition, ICI; intracortical facilitation, ICF) are also most likely impaired in patients with DOC. Reduced ICI and SAI was found in awake patients with anoxic, traumatic, and non-traumatic diffuse brain injury [46]. Moreover, the significant correlation was found between the amount of ICI and the severity of brain injury, while no correlation was found between motor cortex excitability parameters and patient functional level [46].…”

Unravelling motor networks in patients with chronic disorders of consciousness: A promising minimally invasive approach

“…This fact could depend on the exaggerated facilitator tone, which follows the brain-damage-induced thalamocortical deafferentation and, at the same time, attempts to strengthen plastic recovery processes (Lapitskaya et al 2013;Bagnato et al 2012). Corticospinal tract degeneration did not significantly influence our PSTH findings since the P 0 was determinable in all the individuals and the increased P 0 latencies did not significantly differ among DOC patients.…”

The peculiarities of the application of transcranial magnetic therapy and electrical stimulation for the treatment of the patients presenting with various types of stroke

“…ОРИГИНАЛЬНЫЕ СТАТЬИ муляция, изучению электрических и нейрохимиче-ских механизмов воздействия которой посвящено на сегодняшний день большинство исследований [1][2][3][4][5][6][7][8][9][10][11]. Научных работ, посвященных изучению эффектов низкочастотной магнитной стимуляции на головной мозг, значительно меньше [9,11,12].…”