Background
Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the phrenic nerves using invasive electrodes has shown promise in maintaining diaphragm condition by inducing intermittent diaphragm muscle contraction. However, the widespread application of these methods may be limited by their risks as well as the technical and environmental requirements of placement and care. Non‐invasive stimulation would offer a valuable alternative method to maintain diaphragm health while overcoming these limitations.
Methods
We applied non‐invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. Respiratory pressure and flow, diaphragm electromyography and mechanomyography, and ultrasound visualization were used to assess the diaphragmatic response to stimulation. The electrode positions and stimulation parameters were systematically varied in order to investigate the influence of these parameters on the ability to induce diaphragm contraction with non‐invasive stimulation.
Results
We demonstrate that non‐invasive capture of the phrenic nerve is feasible using surface electrodes without the application of pressure, and characterize the stimulation parameters required to achieve therapeutic diaphragm contractions in healthy volunteers. We show that an optimal electrode position for phrenic nerve capture can be identified and that this position does not vary as head orientation is changed. The stimulation parameters required to produce a diaphragm response at this site are characterized and we show that burst stimulation above the activation threshold reliably produces diaphragm contractions sufficient to drive an inspired volume of over 600 ml, indicating the ability to produce significant diaphragmatic work using non‐invasive stimulation.
Conclusion
This opens the possibility of non‐invasive systems, requiring minimal specialist skills to set up, for maintaining diaphragm function in the intensive care setting.
Falls represent a major public health problem in the elderly population. The Timed Up & Go test (TU & Go) is the most used tool to measure this risk of falling, which offers a unique parameter in seconds that represents the dynamic balance. However, it is not determined in which activity the subject presents greater difficulties. For this, a feature-based segmentation method using a single wireless Inertial Measurement Unit (IMU) is proposed in order to analyze data of the inertial sensors to provide a complete report on risks of falls. Twenty-five young subjects and 12 older adults were measured to validate the method proposed with an IMU in the back and with video recording. The measurement system showed similar data compared to the conventional test video recorded, with a Pearson correlation coefficient of 0.9884 and a mean error of 0.17 ± 0.13 s for young subjects, as well as a correlation coefficient of 0.9878 and a mean error of 0.2 ± 0.22 s for older adults. Our methodology allows for identifying all the TU & Go sub–tasks with a single IMU automatically providing information about variables such as: duration of sub–tasks, standing and sitting accelerations, rotation velocity of turning, number of steps during walking and turns, and the inclination degrees of the trunk during standing and sitting.
There is a lack of commercially available low-cost technologies to assess gait clinically in non-controlled environments. As a consequence of this, there has been poor massification of motion measurement technologies that are both objective and reliable in nature. Advances about the study of gait and its interpretation in recent years using inertial sensors have allowed proposing acceptable alternatives for the development of portable and low-cost systems that contribute to people’s health in places and institutions that cannot acquire or maintain the operation of commercially available systems. A system based on a custom single Inertial Measurement Unit and a mobile application is proposed. Thus, an investigation is carried out using methodologies and algorithms found in the literature in order to get the main gait events and the spatial-temporal gait parameters. Twenty healthy Chilean subjects were assessed using a motion capture system simultaneously with the proposed tool. The results show that it is possible to estimate temporal gait parameters with slight differences respect gold--standard. We reach maximum mean differences of -2.35±5.02[step/min] for cadence, 0.03±0.04[sec] for stride time,0.02±0.03[sec] for step time, ±0.02[sec] for a single support time, 0.01±0.02[sec] for double support time and 0.01±0.03[m] for step length. As a result of experimental findings, we propose a new technological tool that can perform gait analysis. Our proposed system is user-friendly, low-cost, and portable. Therefore, we suggest that it could be an attractive technological tool that healthcare professionals could harness to objectively measure gait in environments that are either within the community or controlled. We also suggest that the tool could be used in countries where advanced clinical tools cannot be acquired. Therefore, we propose in this paper that our system is an attractive, alternative system that can be used for gait analysis by health professionals worldwide.
Background
A dry mouth or xerostomia is one of the most common long-term complications following radiotherapy for head and neck cancer and has a negative impact on quality of life in cancer survivors. Transcutaneous electrical nerve stimulation (TENS) is a novel approach to improving saliva flow in these patients.
Objective
To perform a systematic review of studies evaluating TENS in the treatment of radiotherapy induced xerostomia in head and neck cancer patients.
Data collection and analysis
A comprehensive electronic search was performed in PubMed/MEDLINE, the Cochrane Library, and Google Scholar databases for appropriate published studies. The last search was conducted in January 2020. Two review authors assessed all studies identified by the search strategy and carried out data extraction.
Results
Five studies were included in the systematic review which analysed a total of 280 patients with head and neck cancer. Methodological quality and outcomes were evaluated in every study included. The outcome measure was either subjectively assessed or objectively measured. Three studies used conventional TENS therapy to stimulate parotid glands which produced a significant increase in saliva production following therapy. Two studies used acupunctured TENS type to electrically stimulate acupuncture points scattered in the body and they reported improvement in saliva production at the same level as medical treatment. No reported adverse effect of TENS was identified.
Conclusions
This systematic review confirms the safety and feasibility of TENS in the treatment of xerostomia. It is established that commencing daily TENS therapy simultaneously with radiotherapy has the most efficacy. Given the nonspecific parameters used in the included studies, further evidence is needed in order to establish optimal settings and parameters of TENS for treatment of xerostomia.
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