Task-dependent neural control of regions within human genioglossus

Anatomical and imaging evidence suggests neural control of oblique and horizontal compartments of the genioglossus differs. However, neurophysiological evidence for differential control remains elusive. This study aimed to determine whether there are differences in neural drive to the oblique and horizontal regions of the genioglossus during swallowing and tongue protrusion. Adult participants (N=63; 48M) were recruited from a sleep clinic; 41 had Obstructive Sleep Apnoea (OSA: 34M, 8F). Electromyographic (EMG) was recorded at rest (awake, supine) using 4 intramuscular fine-wire electrodes inserted percutaneously into the anterior oblique, posterior oblique, anterior horizontal and posterior horizontal genioglossus. Epiglottic pressure and nasal airflow were also measured. During swallowing, two distinct EMG patterns were observed- a monophasic response (single EMG peak) and a biphasic response (two bursts of EMG). Peak EMG and timing of the peak relative to epiglottic pressure were significantly different between patterns (linear mixed models, p<0.001). Monophasic activation was more likely in the horizontal than oblique region during swallowing (OR=6.83, CI=3.46-13.53, p<0.001). In contrast, during tongue protrusion, activation patterns and EMG magnitude were not different between regions. There were no systematic differences in EMG patterns during swallowing or tongue protrusion between OSA and non-OSA groups. These findings provide evidence for functional differences in the motoneuronal output to the oblique and horizontal compartments, enabling differential task-specific drive. Given this, it is important to identify the compartment from which EMG is acquired. We propose that the EMG patterns during swallowing may be used to identify the compartment where a recording electrode is located.

Beyond Usual Care: A Multidisciplinary Approach Towards the Treatment of Obstructive Sleep Apnoea

Obstructive Sleep Apnoea (OSA) is common and characterised by repeated apnoeas and hypopnoeas while asleep due to collapse of the upper airway. OSA can have a significant impact on physical and mental health and, when left untreated, is associated with increased risk of developing cardiovascular ill health. Besides cardiorespiratory implications excessive daytime sleepiness, morning headaches, limited memory function and lack of concentration are some further symptoms caused by OSA. Continuous Positive Airway Pressure (CPAP) therapy is the evidence-based treatment to maintain upper airway patency in patients with moderate to severe OSA. Proper adherence to CPAP therapy successfully abolishes nocturnal apnoeas and hypopnoeas, and diminishes consequences of uncontrolled OSA, such as treatment resistant hypertension. However, long term adherence to CPAP remains an unresolved limitation of this method. Although alternatives to CPAP therapy may be less efficacious, there is a variety of non-CPAP treatments that includes conventional lifestyle advice, postural advice, the use of mandibular advancement devices (MADs), surgical treatment options, such as uvulopalatopharyngoplasty, tonsillectomy, or maxillomandibular advancement, and the use of electrical stimulation of the upper airway dilator muscles. Hypoglossal Nerve Stimulation is available as an invasive (HNS) and a transcutaneous (TESLA) approach. For the management of “difficult-to-treat” patients with OSA, particularly in those in whom first line therapy proved to be unsuccessful, a multidisciplinary team approach may be helpful to incorporate the available options of non-CPAP therapy and provide appropriate choices. Symptom control, patient-related outcome measures and long-term cardiovascular health should be prioritised when choosing long-term therapies to treat OSA. The inclusion of patients in the choice of successful management options of their condition will facilitate better long-term adherence. Advancing clinical trials in the field will further help to resolve the relative lack of evidence for effective non-CPAP methods.

Factors Affecting Long-Term Compliance of CPAP Treatment—A Single Centre Experience

Continuous positive airway pressure (CPAP) has been the standard treatment of obstructive sleep apnoea/hypopnoea syndrome (OSA) for almost four decades. Though usually effective, this treatment suffers from poor long-term compliance. Therefore, the aim of our one centre retrospective study was to assess factors responsible for treatment failure and long-term compliance. Four hundred subsequent patients diagnosed with OSA and qualified for CPAP treatment were chosen from our database and compliance data were obtained from medical charts. Many differing factors kept patients from starting CPAP or led to termination of treatment. Overall, almost half of patients ended treatment during the mean time of observation of 3.5 years. Survival analysis revealed that 25% of patients failed at a median time of 38.2 months. From several demographic and clinical covariates in Cox’s hazard model, only the presence of a mild OSA, i.e., AHI (apnoea/hypopnoea index) below 15/h was a factor strongly associated with long term CPAP failure. The compliance results of our study are in line with numerous studies addressing this issue. Contrary to them, some demographic or clinical variables that we used in our survival model were not related to CPAP adherence.

Osteopathic Manipulation of the Sphenopalatine Ganglia Versus Sham Manipulation, in Obstructive Sleep Apnoea Syndrom: A Randomised Controlled Trial

(1) Background: osteopathic manipulation of the sphenopalatine ganglia (SPG) blocks the action of postganglionic sensory fibres. This neuromodulation can reduce nasal obstruction and enhance upper airway stability. We investigated the manipulation of the SPG in 31 patients with obstructive sleep apnoea syndrome (OSAS); (2) Methods: Randomised, controlled, double-blind, crossover study. Participants received active (AM), then sham manipulation (SM), or vice versa. The primary endpoint was apnoea-hypopnoea index (AHI). Secondary endpoints were variation of nasal obstruction evaluated by peak nasal inspiratory flow (PNIF) and upper airways stability evaluated by awake critical closing pressure [awake Pcrit]), at 30 min and 24 h. Schirmer’s test and pain were assessed immediately post-manipulation. Tactile/gustatory/olfactory/auditory/nociceptive/visual sensations were recorded. Adverse events were collected throughout. (3) Results: SPG manipulation did not reduce AHI (p = 0.670). PNIF increased post-AM but not post-SM at 30 min (AM-SM: 18 [10; 38] L/min, p = 0.0001) and 24 h (23 [10; 30] L/min, p = 0.001). There was no significant difference on awake Pcrit (AM-SM) at 30 min or 24 h). Sensations were more commonly reported post-AM (100% of patients) than post-SM (37%). Few adverse events and no serious adverse events were reported. (4) Conclusions: SPG manipulation is not supported as a treatment for OSAS but reduced nasal obstruction. This effect remains to be confirmed in a larger sample before using this approach to reduce nasal congestion in CPAP-treated patients or in mild OSAS.