Naro Antonino, Calabrò Rocco Salvatore, Russo Margherita, Leo Antonino, Pollicino Patrizia, Quartarone Angelo, Bramanti Placido
IRCCS Centro Neurolesi Bonino-Pulejo Messina, Italy.
Department of Neurosciences, University of Messina, Italy.
Restor Neurol Neurosci. 2015;33(2):159-76. doi: 10.3233/RNN-140448.
Disorders of consciousness (DOC) diagnosis relies on the presence or absence of purposeful motor responsiveness, which characterizes the minimally conscious state (MCS) and the unresponsive wakefulness syndrome (UWS), respectively. Functional neuroimaging studies have raised the question of possible residual conscious awareness also in clinically-defined UWS patients. The aim of our study was to identify electrophysiological parameters, by means of a transcranial magnetic stimulation approach, which might potentially express the presence of residual networks sustaining fragmentary behavioral patterns, even when no conscious behavior can be observed.
We enrolled 25 severe DOC patients, following post-anoxic or traumatic brain injury and 20 healthy individuals (HC) as control group. Baseline electrophysiological evaluation evidenced, in comparison to HC, a partial preservation of cortical effective connectivity and excitability in clinically defined MCS, whereas these components were absent in clinically defined UWS. Then, we applied an anodal transcranial direct current stimulation (a-tDCS) protocol over the orbitofrontal cortex.
a-tDCS was able to boost cortical connectivity and excitability in all HC, MCS, and to unmask such excitability/connectivity in some UWS patients.
a-tDCS could be useful in identifying residual connectivity markers in clinically-defined UWS, who may lack of purposeful behavior as a result of a motor-output failure.
意识障碍（DOC）的诊断依赖于是否存在有目的的运动反应，这分别是最低意识状态（MCS）和无反应觉醒综合征（UWS）的特征。功能神经影像学研究提出了一个问题，即在临床定义的UWS患者中是否也可能存在残余的意识觉知。我们研究的目的是通过经颅磁刺激方法确定电生理参数，这些参数可能潜在地表明即使在没有观察到有意识行为的情况下，仍存在维持碎片化行为模式的残余网络。
我们招募了25名因缺氧后或创伤性脑损伤导致的严重DOC患者，并以20名健康个体（HC）作为对照组。与HC相比，基线电生理评估表明，在临床定义的MCS中皮质有效连接性和兴奋性部分保留，而在临床定义的UWS中这些成分不存在。然后，我们在眶额皮质上应用阳极经颅直流电刺激（a-tDCS）方案。
a-tDCS能够增强所有HC、MCS的皮质连接性和兴奋性，并在一些UWS患者中揭示出这种兴奋性/连接性。
a-tDCS可能有助于识别临床定义的UWS中的残余连接性标记，这些患者可能由于运动输出失败而缺乏有目的的行为。
