Noninvasive Motor Unit Discharge Assessment

描述（由申请人提供）：临床肌电图（EMG）技术用于各种神经源性和肌源性疾病的鉴别诊断。针肌电图和细导线记录技术也用于基本的运动控制研究，以更好地了解运动单位（MU）的招聘和放电特性。在受控条件下（例如，恒定姿势、缓慢力变化、较低力收缩），这些技术可以识别记录电极附近的各个MU。这些侵入性技术的局限性包括一些感染风险、可能的受试者/患者不适以及需要从肌肉的一小部分进行记录。因此，必须在许多肌肉位置处获得记录以获得代表性MU放电行为样本。侵入式电极不适合于监测电激励沿着肌肉的传播，这可以揭示肌肉纤维膜的动态特性。最近，紧密间隔的表面电极阵列已被证明有足够的空间分辨率来监测活动的个人MUs. Our的总体目标是开发新的设备和分析方法，允许MU动作电位检测和跟踪在非侵入性表面EMG阵列。这项新技术将放宽侵入性技术的几个限制，允许同时记录从许多肌肉区域，以及许多网站沿着肌纤维膜。该技术将具有提供包括个体MU的肌纤维的肌纤维传导速度（MFCV）的估计的额外优点。本项目的具体目标是（a）开发一种新颖的表面电极阵列记录系统，其提供高保真度和灵活的电极蒙太奇选择（现有系统要么是高保真的，要么是灵活的，但不是两者兼而有之），（B）使用阵列开发非侵入性方法以测量标准放电特性沿着MFCV（c）验证标准放电信息与同时测量的针EMG，在试点实验中比较年轻和老年健康受试者在一定范围的力上的MU特性。阵列记录系统将识别从留置电极同时获得的许多MU。在这项工作的实验部分中，我们假设：（a）在较低的力水平期间，活动的MU将倾向于具有比在较高的力水平下招募的那些MU更慢的放电率、更小的尺寸（如通过宏EMG测量的）和更慢的MFCV，以及（B）与老年受试者相比，年轻受试者将倾向于具有更高的放电率、更快的MFCV和更大的MFCV分散度。长期目标是开发一种非侵入性系统，用于记录一套完整的MU放电特征。该系统应导致应用领域，如人体工程学，临床肌电图，和基本的运动控制研究。

DESCRIPTION (provided by applicant):Clinical electromyographic (EMG) techniques are used in the differential diagnosis of various neurogenic and myogenic disorders. Needle EMG and fine wire recording techniques are also used for basic motor control research studies to better understand motor unit (MU) recruitment and discharge properties. Under controlled conditions (e.g., constant posture, slowly force-varying, lower-force contractions), these techniques can identify individual MUs in the vicinity of the recording electrode. Limitations of these invasive techniques include some risk of infection, possible subject/patient discomfort, and the need to record from a small portion of the muscle. Thus, recordings must be obtained at numerous muscle locations to obtain representative MU discharge behavior samples. Invasive electrodes are unsuitable for monitoring the spread of electrical excitation along the muscle, which can reveal dynamic properties of the muscle fiber membrane. Recently, tightly-spaced surface electrode arrays have demonstrated sufficient spatial resolution to monitor the activity of individual MUs. Our overall objective is to develop novel apparatus and analysis methods to permit MU action potential detection and tracking in noninvasive surface EMG arrays. This new technique would relax several restrictions of invasive techniques by allowing simultaneous recording from numerous muscle areas, as well as numerous sites along the muscle fiber membrane. This technique would have the additional advantage of providing estimates of the muscle fiber conduction velocity (MFCV) of muscle fibers comprising individual MUs. The specific aims of this project are to (a) develop a novel surface electrode array recording system that provides both high-fidelity and flexible electrode montage selection (existing systems are either high-fidelity or flexible, but not both), (b) use the array to develop noninvasive methods to measure standard discharge properties along with MFCV (a MU parameter that is not presently measured clinically) and MU size (noninvasive macro-EMG), and (c) validate standard discharge information versus simultaneously measured needle EMG in a pilot experiment comparing MU properties between younger and aged healthy subjects over a range of forces. The array recording system will identify many of the MUs simultaneously obtained from the indwelling electrodes. In the experimental portion of this work, we hypothesize that (a) during lower force levels, the active MUs will tend to have slower firing rates, smaller size (as measured by macroEMG) and slower MFCV than those MUs that are recruited at higher force levels and (b) compared to aged subjects, younger subjects will tend to have higher firing rates, faster MFCVs, and a greater dispersion of MFCVs. The long-term goal is to develop a non-invasive system for recording a complete set of MU discharge characteristics. This system should lead to applications in areas such as ergonomics, clinical EMG, and basic motor control research.