Lewis Richard F, Haburcakova Csilla, Gong Wangsong, Lee Daniel, Wall Conrad, Thompson Lara, Merfeld Daniel M
Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary, Department of Otology and Laryngology at the Harvard Medical School, Boston, MA 02114, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:2277-9. doi: 10.1109/IEMBS.2011.6090573.
We are studying the effectiveness of a semicircular canal prosthesis to improve postural control, perception of spatial orientation, and the VOR in rhesus monkeys with bilateral vestibular hypofunction. Balance is examined by measuring spontaneous sway of the body during quiet stance and postural responses evoked by head turns and rotation of the support surface; perception is measured with a task derived from the subjective visual vertical (SVV) test during static and dynamic rotation in the roll plane; and the angular VOR is measured during rotation about the roll, pitch, and yaw axes. After the normal responses are characterized, bilateral vestibular loss is induced with intratympanic gentamicin, and then multisite stimulating electrodes are chronically implanted into the ampullae of all three canals in one ear. The postural, perceptual, and VOR responses are then characterized in the ablated state, and then bilateral, chronic electrical stimulation is applied to the ampullary nerves using a prosthesis that senses angular head velocity in three-dimensions and uses this information to modulate the rate of current pulses provided by the implanted electrodes. We are currently characterizing two normal monkeys with these paradigms, and vestibular ablation and electrode implantation are planned for the near future. In one prior rhesus monkey tested with this approach, we found that a one-dimensional (posterior canal) prosthesis improved balance during head turns, perceived head orientation during roll tilts, and the VOR in the plane of the instrumented canal. We therefore predict that the more complete information provided by a three-dimensional prosthesis that modulates activity in bilaterally-paired canals will exceed the benefits provided by the one-dimensional, unilateral approach used in our preliminary studies.
我们正在研究一种半规管假体对改善双侧前庭功能减退的恒河猴姿势控制、空间定向感知和前庭眼反射（VOR）的有效性。通过测量安静站立时身体的自发摆动以及头部转动和支撑面旋转引发的姿势反应来检查平衡；通过在横滚平面静态和动态旋转期间进行的一项源自主观视觉垂直（SVV）测试的任务来测量感知；通过在绕横滚、俯仰和偏航轴旋转期间测量角前庭眼反射。在确定正常反应特征后，通过鼓室内注射庆大霉素诱导双侧前庭丧失，然后将多部位刺激电极长期植入一只耳朵的所有三个半规管壶腹。然后在失神经状态下确定姿势、感知和前庭眼反射反应特征，接着使用一种能三维感知头部角速度并利用该信息调节植入电极提供的电流脉冲频率的假体，对壶腹神经进行双侧慢性电刺激。我们目前正在用这些范式研究两只正常猴子，并且计划在不久的将来进行前庭切除和电极植入。在之前用这种方法测试的一只恒河猴中，我们发现一维（后半规管）假体改善了头部转动时的平衡、横滚倾斜时的头部定向感知以及在植入半规管平面内的前庭眼反射。因此，我们预测，一种能调节双侧配对半规管活动的三维假体所提供的更完整信息，将超过我们初步研究中使用的一维单侧方法所带来的益处。
