A Non-Invasive Medical Device for Parkinson's Patients with Episodes of Freezing of Gait.

A critical symptom of Parkinson's disease (PD) is the occurrence of Freezing of Gait (FOG), an episodic disorder that causes frequent falls and consequential injuries in PD patients. There are various auditory, visual, tactile, and other types of stimulation interventions that can be used to induce PD patients to escape FOG episodes. In this article, we describe a low cost wearable system for non-invasive gait monitoring and external delivery of superficial vibratory stimulation to the lower extremities triggered by FOG episodes. The intended purpose is to reduce the duration of the FOG episode, thus allowing prompt resumption of gait to prevent major injuries. The system, based on an Android mobile application, uses a tri-axial accelerometer device for gait data acquisition. Gathered data is processed via a discrete wavelet transform-based algorithm that precisely detects FOG episodes in real time. Detection activates external vibratory stimulation of the legs to reduce FOG time. The integration of detection and stimulation in one low cost device is the chief novel contribution of this work. We present analyses of sensitivity, specificity and effectiveness of the proposed system to validate its usefulness.

The impact of bilateral subthalamic deep brain stimulation on long-latency event-related potentials.

The analysis of long-latency event-related potentials (ERPs) is of importance in the evaluation of certain cognitive functions and in following their subsequent changes. The aim of the present study was to investigate whether deep brain stimulation (DBS) itself can cause changes in the configuration of the ERPs. Using a standard oddball auditory paradigm, we elicited auditory cognitive ERPs in 23 Parkinson's disease patients (in both DBS-ON and DBS-OFF conditions) and in 14 healthy controls. The P200 and P300 amplitudes and latencies, the motor reaction times and the accuracy of button pressing were compared between the DBS-ON and DBS-OFF states and subsequently correlated with the applied stimulation voltage and disease duration. Comparison of the DBS-ON and DBS-OFF conditions revealed that neither the amplitude nor the latency of the examined ERP components changed significantly. However, the behavioral and attentional aspects (e.g. the accuracy of the button pressing responses to the target signal) definitely improved after the DBS was turned on. Positive correlations were demonstrated between the P300 amplitudes over the central and frontal regions and the optimal stimulation voltage and between the disease duration and P300 latencies over the Cz and Fz sites. In conclusion, our data indicate that DBS may have different impacts on various electrophysiological parameters during the oddball paradigm.

Implanted deep brain stimulator and 1.0-Tesla magnetic resonance imaging.

There is a great need for MRI examinations of patients who have previously undergone deep brain stimulator (DBS) implantation. The current guidelines pertain only to a 1.5-Tesla horizontal-bore scanner complying with strict safety regulations. Moreover, almost all published in vitro and in vivo studies concerning patient safety are carried out on 1.5 Tesla MR scanners. The aim of our work is to share our clinical experience of 1.0-Tesla brain MR imaging. During the past four years, 34 patients with different types of implanted DBS systems underwent 1.0-Tesla MR examinations to answer diagnostic or clinical questions. Apart from the scanner type applied, all other safety instructions were strictly followed. The MRI itself made no significant difference to the measured impedances or the stimulation parameters required to achieve the optimal therapeutic results. From theoretical considerations, it may be assumed that 1.0-Tesla MRI can be performed safely on DBS-implanted patients, provided that all other recommendations are adhered to.