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    Interventional procedure overview of daytime intraoral neuromuscular electrical tongue stimulation using a removable device for obstructive sleep apnoea

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    Evidence summary

    Population and studies description

    This interventional procedure overview is based on 128 patients with primary snoring and mild OSA from 1 single-arm clinical trial (Baptista 2021; Kotecha 2021; Nokes 2022) and 1 pilot study (Wessolleck 2018). The clinical trial by Baptista (2021) was a multicentred trial with patients recruited from the UK and Spain, and expanded the findings from Kotecha (2021) which included patients from the UK. Nokes (2022) was a secondary analysis of the subgroup of patients with mild OSA included in Baptista (2021). The pilot study by Wessolleck (2018) was a bicentric study, carried out in the UK and Germany. This is a rapid review of the literature, and a flow chart of the complete selection process is shown in figure 1. This overview presents 2 studies (4 papers) as the key evidence in table 2 and table 3, and lists additional relevant studies in table 5.

    Of the 128 patients, 74 patients had the procedure for mild OSA. The clinical trial and the pilot study did not report the recruitment periods. Both studies had 2-week follow ups after the 6-week therapy. The mean age of patients ranged from 43 (Wessolleck 2018) to 46 years (Baptista 2021), and 66% of patients were male. The mean BMI was about 27 kg/m2, and the mean AHI was from 6.47 (Baptista 2021) to 9.3 events per hour (Wessolleck 2018). Table 2 presents study details.

    Figure 1 Flow chart of study selection

    Table 2 Study details

    Study no.

    First author, date

    Country

    Patients (male: female)

    Age (years)

    AHI (events per hour)

    Study design

    Inclusion criteria

    Intervention

    Follow up

    1

    Baptista 2021

    UK and Spain

    115 (73:42)

    (50 primary snoring; 65 mild OSA)

    Mean 46

    Mean 6.47

    Single-arm trial

    (NCT03829956)

    age greater than 18 years, having a live-in partner to report on snoring (VAS), and a history of more than 6 months of habitual snoring of >5 days per week, AHI <15 and BMI ≤35.

    Intraoral neuromuscular electrical tongue stimulation (eXciteOSA device) for 20 minutes once daily for 6 weeks.

    Stimulus intensity (mean): level 5.9 at week 1 to 8.9 at week 6.

    Therapy adherence: 83%

    2 weeks after the 6-week therapy.

    Kotecha 2021

    UK

    70 (44:16)

    (32 primary snoring; 38 mild OSA)

    Mean 46

    Mean 5.95

    Same as Baptista (2021)

    Same as Baptista (2021)

    Intervention: same as Baptista (2021)

    Stimulus intensity (mean): leave 6 at the starting point to level 9.3 at week 6.

    Therapy adherence: 83.3%

    Same as Baptista (2021)

    Nokes 2022 (secondary analysis of patients with mild OSA)

    65 (44:21)

    Median 49

    Median 11.4 (range 5 to 14.9)

    Same as Baptista (2021)

    patients with an AHI ≥5 and <15 events per hour.

    intervention: same as Baptista (2021)

    Therapy adherence: 85%

    Same as Baptista (2021)

    2

    Wessolleck 2018

    UK and Germany

    13 (11:2) (4 primary snoring; 9 mild OSA)

    Mean 43.2

    Mean 9.3

    Pilot study

    Aged 20 to 65 years, history of more than 6 months' continuous snoring (>5 times per week), and bedpartner to document snoring intensity.

    Intraoral neuromuscular electrical tongue stimulation (eXciteOSA device) for 20 minutes twice daily for 6 weeks.

    2 weeks after the 6-week therapy.

    Table 3 Study outcomes

    First author, year

    Efficacy outcomes

    Safety outcomes

    Baptista 2021

    Mean reduction in % time snoring:

    • 40 dB (all snoring): 41% (p<0.001, 95% CI 10.5 to 15.3%)

    • 45 dB (moderate snoring): 52% (p<0.001, 95% CI 4.74 to 8.39%)

    • 50 dB (epic snoring): 54% (p<0.001, 95% CI 2.30 to 5.06%)

    • Partners estimation: 39% reduction (p<0.001)

    AHI (mean, events per hour): pretherapy, 6.85; posttherapy, 5.03; p<0.001

    ODI 4% (mean, events per hour): pretherapy, 5.68; posttherapy, 4.33; p<0.001

    ESS (mean):

    • patients: pretherapy, 8.4; posttherapy, 5.8; mean reduction by week 6, 2.6; p<0.01; 95% CI 1.98 to 3.27

    • partners: pretherapy, 6.2; posttherapy, 5.7; p=0.22

    PSQI (mean):

    • patients: pretherapy, 7.16; posttherapy, 5.75; p<0.001, 95% CI 0.89 to 1.92

    • partners: pretherapy, 6.87; posttherapy, 5.94; p=0.02; 95% CI 0.15 to 1.68

    VAS (mean):

    • pretherapy, 6.1; week 5/6, 3.7; p<0.001; 95% CI 2.0 to 2.69

    • week 7/8, 3.8

    Side effects: n=17 (15%), with the most common side effect of oral pooling of saliva during utilisation (n=12, 10.4%)

    Additional adverse events:

    Tongue discomfort: n=10 (8.7%)

    Tooth discomfort: n=7 (6.1%)

    Tongue tingling: n=7 (6.1%)

    Filling sensitivity: n=4 (3.5%)

    Metallic taste: n=3 (2.6%)

    Gagging: n=2 (1.7%)

    Tightness in the jaw: n=1 (0.9%)

    Kotecha 2021

    Proportion of patients who experienced a >25% reduction in snoring time at >40 dB: 74.3%

    Mean reduction in % time snoring:

    • 40 dB (all snoring): 40.84% (p<0.001, 95% CI 34.3% to 47.4%)

    • 45 dB (moderate snoring): 46.64% (p<0.001, 95% CI 37.60% to 55.67%)

    • 50 dB (epic snoring): 40.94% (p<0.001, 95% CI 30.66% to 51.23%)

    AHI (mean, events per hour):

    • All patients: pretherapy, 5.94; posttherapy, 5.37

    • Mild OSA (n=38): pretherapy, 9.8; posttherapy, 4.7; p<0.001

    ODI (mean, events per hour):

    • All patients: pretherapy, 4.92; posttherapy, 4.73

    • Mild OSA (n=38): pretherapy, 7.8; posttherapy, 4.3; p<0.001

    ESS (mean):

    • All patients: pretherapy, 9.0; posttherapy, 6.5; p<0.001

    • Mild OSA (n=38): pretherapy, 9.0; posttherapy, 5.1; p<0.001

    • Bedpartners: pretherapy, 5.8; posttherapy, 5.0; p=0.205

    PSQI (mean):

    • All patients: pretherapy, 7.0; posttherapy, 5.9; p=0.004

    • Bedpartners: pretherapy, 7.3; posttherapy, 6.3; p=0.029

    VAS (n=61): pretherapy, 5.88; week 5/6, 3.98; p<0.001 (this benefit was sustained at week 7/8)

    Side effects (mild symptoms): n=11

    Excess salivation: n=10 (14.2%)

    Tongue tingling/discomfort: n=7 (10%)

    Filling sensitivity: n=3 (4.2%)

    Metallic taste and gagging sensation: n=3 (4.29%)

    Tightness in the jaw: n=1 (4.3%)

    Nokes 2022

    % time snoring >40 dB:

    • All patients: pretherapy, 36.5%; posttherapy, 21.5%; mean reduction, 15.0±15.4% (95% CI 11.1 to 18.8%), p<0.01

    • Responders (n=51): pretherapy, 37.1%; posttherapy, 20.2%; mean reduction, 16.9±16.7% (95% CI 12.2 to 21.6%), p<0.01

    Patients who experienced some reduction in their AHI were considered "responders".

    • ≥50% reduction in AHI (n=28): pretherapy, 39.0%; posttherapy, 20.7%; mean reduction, 18.3±20.8% (95% CI 10.2 to 26.4%), p<0.01

    AHI (mean[±SD], events per hour):

    • All patients (n=65): pretherapy, 10.2; posttherapy, 6.8; mean reduction, 3.4±5.0 (95% CI 2.2 to 4.7), p<0.01

    • Responders (n=51): pretherapy, 10.4; posttherapy, 5.0; mean reduction, 5.4±2.8 (95% CI 4.7 to 6.2), p<0.01

    • ≥50% reduction in AHI (n=28): pretherapy, 10.8; posttherapy, 3.5; mean reduction, 7.2±2.1 (95% CI 6.4 to 8.0), p<0.01

    ODI 4% (mean[±SD], events per hour):

    • All patients: pretherapy, 8.4; posttherapy, 5.9; mean reduction, 2.5±4.6 (95% CI 1.4 to 3.6), p<0.01

    • Responders (n=51): pretherapy, 8.6; posttherapy, 4.3; mean reduction, 4.3±2.7 (95% CI 3.6 to 5.1), p<0.01

    • ≥50% reduction in AHI (n=28): pretherapy, 9.0; posttherapy, 3.2; mean reduction, 5.8±2.1 (95% CI 5.0 to 6.6), p<0.01

    ESS (mean[±SD]):

    • All patients: pretherapy, 8.7; posttherapy, 5.3; mean reduction, 3.4±4.1 (95% CI 2.4 to 4.4), p<0.01

    • Responders (n=51): pretherapy, 9.3; posttherapy, 5.4; mean reduction, 3.9±3.7 (95% CI 2.8 to 4.9), p<0.01

    • ≥50% reduction in AHI (n=28): pretherapy, 9.5; posttherapy, 5.2; mean reduction, 4.4±4.3 (95% CI 2.7 to 6.0), p<0.01

    PSQI (mean[±SD]):

    • All patients: pretherapy, 7.3; posttherapy, 5.9; mean reduction, 1.4±2.8 (95% CI 0.7 to 2.1), p<0.01

    • Responders (n=51): pretherapy, 7.2; posttherapy, 5.5; mean reduction, 1.7±2.3 (95% CI 1.0 to 2.3), p<0.01

    • ≥50% reduction in AHI (n=28): pretherapy, 6.6; posttherapy, 4.8; mean reduction, 1.8±2.6 (95% CI 0.8 to 2.8), p<0.01

    VAS (mean[±SD]): pretherapy, 6.3; posttherapy, 3.9; mean reduction, 2.4±1.8 (95% CI 1.9 to 2.9), p<0.01

    Adverse events were minor, infrequent, and transient including excess drooling, tongue tingling or discomfort, tooth discomfort, and gagging (exact data was not reported).

    Wessolleck 2018

    VAS (mean±SD):

    • All patients (n=13): pretherapy, 5.66±1.10; week 5/6, 3.16±2.58 (p<0.05 compared with pretherapy); week 7/8, 3.28±2.33

    • AHI <10 (n=6): pretherapy, 5.44±1.16; week 5/6, 1.46±1.03; week 7/8, 1.66±1.11

    • AHI ≥10 (n=7): pretherapy, 5.85±0.94; week 5/6, 4.61±3.16; week 7/8, 4.68±2.05

    A subjective feeling of electrical stimulation in the mouth during the training phase as a short "twitching" or "tingling" (exact data was not reported).

    Procedure technique

    In the 2 studies, the procedure used the eXciteOSA® device (formerly known as SnooZeal©), which consists of 3 components: a control unit, a washable electrode mouthpiece, and a smartphone application. This device works by delivering bipolar biphasic current (0 to 20 Hz) through a washable flexible mouthpiece with 4 electrodes placed in pairs above and below the tongue to ensure vertical and diagonal patterns of stimulation.

    Patients were instructed to use the device during wakefulness for 20 minutes once daily (Baptista 2021) or 20 minutes twice daily (Wessolleck 2018) for 6 weeks. They had full control over the intensity levels during therapy sessions and on/off functionality of the control unit and mouthpiece. They were advised to use the maximal tolerable intensity without discomfort. The clinical trial detailed stimulus intensity (from level 6 at week 1 to level 9 at week 6) and therapy adherence (83%; Baptista 2021; Kotecha 2021).

    Efficacy

    Change in time snoring

    Change in the proportion of time snoring before and after the therapy was reported in the clinical trial. In patients with primary snoring and mild OSA, Baptista (2021) found that there were statistically significant reductions in time snoring louder than 40 dB (mean reduction, 41%), 45 dB (mean reduction, 52%) and 50 dB (mean reduction, 54%) in 115 patients recruited from the UK and Spain. Kotecha 2021 also found statistically significant reductions in time snoring at these thresholds (mean reduction of 41%, 47% and 41%, respectively) in 70 patients selected from the UK only. In patients with mild OSA (n=65), secondary analysis demonstrated a statistically significant reduction in time spent snoring louder than 40 dB, with a mean reduction of 15% (Nokes 2022).

    Respiratory parameters (AHI and ODI)

    Respiratory parameters were assessed before and after the therapy in the clinical trial. In patients with primary snoring and mild OSA, Baptista (2021) reported that there were statistically significant reductions after the therapy in the mean AHI and ODI based on the 4% desaturation threshold (AHI: from 6.85 to 5.03 events per hour; ODI: from 5.68 to 4.33 events per hour). However, Kotecha (2021) described that the reductions in AHI and ODI were not statistically significant (AHI, from 5.94 to 5.37 events per hour; ODI, from 4.92 to 4.73 events per hour). Secondary analysis of patients with mild OSA showed that there were statistically significant reductions in AHI (from 10.2 to 6.8 events per hour; mean reduction, 3.4 events per hour) and ODI 4% (from 8.4 to 5.9 events per hour; mean reduction, 2.5 events per hour) and that the oxygen saturation did not statistically significantly change over time (Nokes 2022).

    Sleep quality (ESS and PSQI)

    Sleep quality questionnaires were completed by both patients and their bedpartners before, and at the end of, the therapy in the clinical trial. The patient-reported outcomes showed a statistically significant reduction in the mean ESS in patients with primary snoring and mild OSA (mean reduction of 2.6 in Baptista 2021; mean reduction of 2.5 in Kotecha 2021), and in patients with mild OSA (mean reduction, 3.4; Nokes 2022). Based on the bedpartner-reported data, the reduction in ESS was not statistically significant (from 6.2 to 5.7 in Baptista 2021; from 5.8 to 5.0 in Kotecha 2021).

    In terms of PSQI, the patient-reported data revealed that there was a statistically significant reduction in patients with primary snoring and mild OSA (from 7.16 to 5.75 in Baptista 2021; from 7.0 to 5.9 in Kotecha 2021), and in patients with mild OSA only (mean reduction, 1.4; Nokes 2022). The data reported by bedpartners also presented a statistically significant reduction in the mean PSQI (from 6.87 to 5.94 in Baptista 2021; from 7.3 to 6.3 in Kotecha 2021).

    Snoring intensity (VAS)

    VAS snoring intensity was evaluated based on bedpartner's perception, and a statistically significant reduction after the therapy was found in 2 studies. In the clinical trial, Baptista (2021) reported that there was a statistically significant reduction in VAS reported by bedpartners of patients with primary snoring and mild OSA at the end of therapy, and this benefit was sustained at 2 weeks after the therapy (pretherapy, 6.1; week 5/6, 3.7; week 7/8, 3.8). Kotecha 2021 found a similar effect in VAS reduction up to 2 weeks post therapy. Secondary analysis of patients with mild OSA also showed a statistically significant reduction in bedpartner-reported VAS at the end of the therapy (mean reduction, 2.4±1.8; Nokes 2022).

    In the pilot study of 13 patients with primary snoring and mild OSA, Wessolleck (2018) reported that the mean VAS statistically significantly decreased at the end of the therapy (pretherapy, 5.66±1.10; week 5/6, 3.16±2.58), and this effect remained stable up to 2 weeks after the therapy (3.28±2.33). In patients with AHI ≥10 events per hour (n=7), the mean VAS decreased from 5.85±0.94 at baseline to 4.61±3.16 at week 5/6, and 4.68±2.05 at 2 weeks after the therapy.

    Safety

    Baptista (2021) reported that side effects were experienced in 17 patients (15%), with the most common side effect being oral pooling of saliva during utilisation (n=12, 10%). Additional adverse events included tongue discomfort (n=10, 9%), tooth discomfort (n=7, 6%), tongue tingling (n=7, 6%), filling sensitivity (n=4, 4%), metallic taste (n=3, 3%), gagging (n=2, 2%) and tightness in the jaw (n=1, 1%). In Wessolleck (2018), patients experienced a subjective feeling of electrical stimulation in the mouth during the training phase as a short 'twitching' or 'tingling'. No serious adverse events were reported in both studies.

    Anecdotal and theoretical adverse events

    Expert advice was sought from consultants who have been nominated or ratified by their professional Society or Royal College. They were asked if they knew of any other adverse events for this procedure that they had heard about (anecdotal), which were not reported in the literature. They were also asked if they thought there were other adverse events that might possibly occur, even if they have never happened (theoretical).

    They listed the following anecdotal and/or theoretical adverse events: nerve injury, failure to work, and initial complications from use.

    Four professional expert questionnaires for this procedure were submitted. Of the 4 professional experts, 3 experts agreed for the information they provided to be published on the website. Find full details of what the professional experts said about the procedure in the specialist advice questionnaires for this procedure.

    Validity and generalisability

    Two studies (4 papers) were included in the key evidence. The clinical trial by Baptista 2021 was suitably powered, even though a potential dropout rate was not compensated. This open-label trial had a follow-up duration of 2 weeks after the 6-week therapy. The proportion of patients with primary snoring and mild OSA who did not complete the study and were excluded from the analyses was 8% (10/125) in Baptista (2021) and 19% (3/16) in Wessolleck (2018). Reasons for withdrawing varied. Both studies were sponsored by the manufacturer.

    Evidence showed improvements in snoring time, respiratory parameters, sleep quality and snoring intensity, with most improvements being statistically significant. All adverse events were minor and short lived. However, the absence of controls (sham comparator) means that the observed improvements might have been a result of a placebo effect. This possibility might be partially mitigated by the inclusion of objectively assessed endpoints. In addition, given the short follow-up duration, hard outcomes such as cardiovascular disease endpoints or neurocognitive performance were not assessed. These outcomes remain the key endpoints to consider and should be evaluated.

    Further studies have been planned to include 3- and 6-month follow-up evaluations to test whether the improvements noted at 2 weeks posttherapy would sustain for a longer duration (Kotecha 2021). To date, there are 4 ongoing trials identified - 1 single-arm trial with an estimated enrolment of 200 patients and 3 trials including parallel arms:

    Despite these ongoing studies, further research is needed to include larger samples, capture long-term outcomes (1 year or longer), and conduct comparative analysis.