An ambulatory gait analysis method using body-attached gyroscopes to estimate spatio-temporal parameters of gait has been proposed and validated against a reference system for normal and pathologic gait. Later, ten Parkinson's disease (PD) patients with subthalamic nucleus deep brain stimulation (STN-DBS) implantation participated in gait measurements using our device. They walked one to three times on a 20-m walkway. Patients did the test twice: once STN-DBS was ON and once 180 min after turning it OFF. A group of ten age-matched normal subjects were also measured as controls. For each gait cycle, spatio-temporal parameters such as stride length (SL), stride velocity (SV), stance (ST), double support (DS), and gait cycle time (GC) were calculated. We found that PD patients had significantly different gait parameters comparing to controls. They had 52% less SV, 60% less SL, and 40% longer GC. Also they had significantly longer ST and DS (11% and 59% more, respectively) than controls. STN-DBS significantly improved gait parameters. During the stim ON period, PD patients had 31% faster SV, 26% longer SL, 6% shorter ST, and 26% shorter DS. GC, however, was not significantly different. Some of the gait parameters had high correlation with Unified Parkinson's Disease Rating Scale (UPDRS) subscores including SL with a significant correlation (r = -0.90) with UPDRS gait subscore. We concluded that our method provides a simple yet effective way of ambulatory gait analysis in PD patients with results confirming those obtained from much more complex and expensive methods used in gait labs.

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This paper presents a low-voltage low-power high-speed superregenerative receiver operating in the 2.4-GHz industrial-scientific-medical band. The receiver uses an architecture in which, thanks to the presence of a phase-locked loop, the quench oscillator is operated synchronously with the received data at a quench frequency equal to the data rate. This mode of operation has several benefits. Firstly, the traditional problem of poor selectivity in this type of receiver is to a large extent overcome. Secondly, considerably higher data rates can be achieved than with classical receivers. Thirdly, the bit envelope can be matched to the superregenerative oscillator, which improves sensitivity. The receiver includes an RF front end optimized to support high quench frequencies at low supply voltages, responding to today's increasing demand for high speed and low power consumption. The prototype implemented is very simple and achieves a data rate of 11 Mb/s with a current consumption of 1.75 mA at a supply voltage of 1.2 V-an excellent tradeoff between cost, performance, and power consumption.

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Two groups of 10 Parkinson's disease (PD) patients and 10 age-matched Normal subjects performing normal life activities were recorded using a portable recorder and 3D gyroscopes. PD patients had sub-thalamic stimulation implantation for 2043 months. The PD patients performed the test twice: with and without stimulation. Bradykinesia and Tremor of hands in PD patients was quantified and strong correlation between this objective method and UPDRS clinical score was found.

A study on ultrasound link for wireless energy transmission dedicated to deeply implanted medical devices is presented. The selection of the frequency to avoid biological side effects (e.g., cavitations), the choice of the power amplifier to drive the external transducers and the design of the rectifier to maximize the energy extraction from the implanted transducer are described in details. The link efficiency is characterized in water using a phantom material for a transmitter-receiver distance of 105 mm, transducers active area of 30 mm × 96 mm and 5 mm × 10 mm, respectively, and a system efficiency of 1.6% is measured.