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Advanced Optical Imaging in the Study of Acute and Chronic Response to Implanted Neural Interfaces
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Cristin G. Welle, Daniel X. Hammer
Implanted medical devices that interface with the nervous system are currently used to diagnose and treat a wide variety of neurological and psychiatric disorders and impairments. The acceptance of these devices is likely to grow over the next decade to the extent that they are demonstrated to provide benefit to patients who are resistant to treatment by pharmaceutical or other interventions. Neurostimulation devices treat medical conditions such as chronic pain, Parkinson’s disease, essential tremor, epilepsy, hearing loss, and urinary incontinence, among others. There are an estimated 800,000 implanted neurostimulation devices in patients worldwide, and the market share is expected to grow (Medtech Insight 2013). Neural recording devices, which detect neural signals, are currently marketed for epilepsy monitoring and brain mapping. Several medical devices recently approved by the U.S. Food and Drug Administration (FDA) include both stimulation and recording elements. These include a closed-loop system, the NeuroPace Responsive Neurostimulation System for epilepsy, which detects brain electrical signals and provides stimulation to interrupt seizures. Similarly, the Inspire Upper Airway stimulation system to treat sleep apnea detects ventilatory effort and responds with stimulation of the hypoglossal nerve to open the airway. The closed-loop detection/therapy combination of neural sensing and stimulation in a single device platform has the potential to increase the therapeutic potency of future devices.
Drug-induced acute upper airway obstruction
Published in Philippe Camus, Edward C Rosenow, Drug-induced and Iatrogenic Respiratory Disease, 2010
Michael Lippmann, Ganesan Murali
Obstructive sleep apnoea (OSA) is an anatomical problem. A review of the anatomy of the oropharyngeal muscles assists in the understanding of the mechanism of upper airway obstruction during sleep. Movement of the tongue occurs with the help of four strong muscles: genioglossus for protrusion; hypoglossus for depression; styloglossus for pulling the tongue upwards and backwards; and palatoglossus for pulling the posterior part of the tongue upwards. The hypoglossal nerve innervates all the tongue muscles except the palatopharyngeus, which is supplied by the vagus-pharyngeal plexus.
A computational model of upper airway respiratory function with muscular coupling
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Olusegun J. Ilegbusi, Don Nadun S. Kuruppumullage, Matthew Schiefer, Kingman P. Strohl
For the genioglossus (the major upper airway dilator muscle), we assumed that muscle contraction occurred for 3s along an anterior-posterior direction. The strength of the contraction was induced through a time-force function in the FE model. In reality, the contraction of muscle tissues is activated through impulses delivered through the motor nerve network, for instance, the hypoglossal nerve for genioglossus in the tongue (Eisele et al. 1997; Yoo and Durand 2005). Figure 3 shows the activation profile used in this study. The activation duration was chosen to mirror a typical neurostimulation procedure. The magnitude of the force at this stage was chosen through preliminary simulations with varying forces until a profile produced airway openings at the epiglottis level typically observed in trial applications of neurostimulation. The activation profile was used as a distributed load within the region of genioglossus muscle. We assumed the airway structure was initially at rest. Therefore, there was no activation for the first 3s of the simulation in order to allow the airway structure to reach stable condition under gravity in the lateral-posterior direction.
Simulated volume loss in the base of tongue in a virtual swallowing model
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2019
Jing Wang, Andrew Kenneth Ho, Georgina Papadopoulos-Nydam, Jana Rieger, Yoko Inamoto, Sidney Fels, Eiichi Saitoh, Chuanbin Guo, Daniel Aalto
Swallowing problems after oropharyngeal cancer treatment are common and negatively impact quality of life. The main treatment modalities include surgical removal of tumour and/or radiation therapy (with or without chemotherapy). Large lesions in the base of tongue (BOT) often require surgical resection, resulting in a bulk defect that might increase with dehydration, radiotherapy or hypoglossal nerve palsy (Wu et al. 2000; Lin et al. 2002; Urashima et al. 2006). The volume decrease impacts pressure generation between the posterior pharyngeal wall and BOT and thus reduces the driving force of the tongue during swallowing (Walther 1995). Tongue reconstruction can restore volume (Yun et al. 2010; Bittermann et al. 2015; Tarsitano et al. 2016). While there is evidence to establish an association between insufficient BOT volume and swallowing impairment, (McConnel et al. 1994; Zuydam et al. 2000; Kimata et al. 2003; Smith et al. 2008; Yun et al. 2010) it is challenging to tease apart the contribution of the volume loss from other (possibly confounding) variables such as soft tissue sclerosis, impaired muscular movement, discoordination of muscle activity, resistance from the upper esophageal sphincter, compensational failure, negative and positive pressure within the pharynx, and strength and tension of the BOT based on observational data alone (Walther 1995; Pauloski and Logemann 2000). Thus, the biomechanical causes of dysphagia still are not well understood (Kimata et al. 2003; Pauloski 2008; Myers et al. 2012; Al-Qahtani et al. 2015).
Structure and variability in human tongue muscle anatomy
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Maureen Stone, Jonghye Woo, Junghoon Lee, Tera Poole, Amy Seagraves, Michael Chung, Eric Kim, Emi Z. Murano, Jerry L. Prince, Silvia S. Blemker
The only function reflected in the tongue’s neuromuscular organisation is protrusion and retrusion. The protrusor and retrusor muscles are represented separately in the ventral versus dorsal regions of the hypoglossal nucleus (HGN), as well as the lateral versus medial branches of the hypoglossal nerve, consistent with antagonistic behaviour of these two sets of muscles (McClung & Goldberg 1999, 2000). However, these regionalised sections of the HGN are embryologically based, and not functionally important as co-contraction of the tongue musculature develops early for speech. Protrusion is used by newborns who suckle using a tongue-thrust motion. In infancy, however, tongue motion rapidly becomes differentiated for speech (Davis & MacNeilage 1995). In adults, even the simplest speech gestures utilise co-contraction of the tongue muscles (cf. MacNeilage & Sholes 1964; vowels – Miyawaki 1975; Baer et al. 1988). Thus, muscle innervation and muscle function are not tightly linked due to co-activation.