Trial Outcomes & Findings for Eye Muscle Needle Electromyogram (EMu) Study (NCT NCT03895632)

NCT ID: NCT03895632

Last Updated: 2022-07-18

Results Overview

The continuous change in the EMG signal as the needle is (a) distal to, (b) approaches, and (c) enters, the target extraocular muscle. Welch's periodogram estimator (Hamming window, 256-point FFT, 50% overlap) was applied to each of the three signal segments described above to obtain an estimate of the PSD of the signal. A robust linear model was fit to estimate the α (slope) parameter of each PSD plot.

• Recruitment status: COMPLETED
• Target enrollment: 25 participants
• Primary outcome timeframe: Approximately 5 minutes, i.e. immediately prior to needle insertion until Botulinum toxin (BTX) delivery and needle withdrawal
• Results posted on: 2022-07-18

Participant Flow

Participant milestones

Measure	Observation Patients with strabismus being treated with injections of Botulinum toxin (BTX). BTX dosage varied from 0.5 to 6.0 Units given in a single injection of fluid.
Overall Study STARTED	25
Overall Study COMPLETED	25
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Sex/Gender data were not collected

Baseline characteristics by cohort

Measure	Observation n=25 Participants Participants who were recruited and had their data recorded for this observational study.
Age, Continuous	55 years n=25 Participants
Rectus muscle Medial rectus	8 Participants n=25 Participants
Rectus muscle Lateral rectus	17 Participants n=25 Participants
Electrode distance	13 mm n=25 Participants

PRIMARY outcome

Timeframe: Approximately 5 minutes, i.e. immediately prior to needle insertion until Botulinum toxin (BTX) delivery and needle withdrawal

The continuous change in the EMG signal as the needle is (a) distal to, (b) approaches, and (c) enters, the target extraocular muscle.

Welch's periodogram estimator (Hamming window, 256-point FFT, 50% overlap) was applied to each of the three signal segments described above to obtain an estimate of the PSD of the signal. A robust linear model was fit to estimate the α (slope) parameter of each PSD plot.

Outcome measures

Measure	Observation n=25 Participants Participants who were recruited and had their data recorded for this observational study.
α (Slope) Parameter of the Electromyogram (EMG) Signal Power Spectral Density (PSD) Plot as Needle Approaches Then Enters Muscle. Off-target	1.49 log (mV^2 / Hz) / log (Hz) Interval 1.22 to 1.76
α (Slope) Parameter of the Electromyogram (EMG) Signal Power Spectral Density (PSD) Plot as Needle Approaches Then Enters Muscle. Approaching-target	2.86 log (mV^2 / Hz) / log (Hz) Interval 2.59 to 3.13
α (Slope) Parameter of the Electromyogram (EMG) Signal Power Spectral Density (PSD) Plot as Needle Approaches Then Enters Muscle. On-target	3.56 log (mV^2 / Hz) / log (Hz) Interval 3.29 to 3.83

SECONDARY outcome

Timeframe: Approximately 5 minutes, i.e. immediately prior to needle insertion until Botulinum toxin (BTX) delivery and needle withdrawal

Clinician's score of the step change from baseline EMG to 'active' EMG level heard immediately prior to delivery of Botulinum toxin (BTX) from 1-5. Value from 1 = no significant step change heard, to 5 = a very clear step change heard.

Outcome measures

Measure	Observation n=25 Participants Participants who were recruited and had their data recorded for this observational study.
Clinical Score of EMG Change	4.6 score on a scale Interval 3.0 to 5.0

SECONDARY outcome

Timeframe: Approximately 5 minutes, i.e. immediately prior to needle insertion until Botulinum toxin (BTX) delivery and needle withdrawal

Clinician's score of their confidence in accurate needle placement with respect to the target muscle. Given as a percentage, a higher score indicates more confidence in accurate needle placement.

Outcome measures

Measure	Observation n=25 Participants Participants who were recruited and had their data recorded for this observational study.
Clinical Score of Needle Placement Accuracy	87.6 percentage of confidence Interval 50.0 to 95.0

SECONDARY outcome

Timeframe: Approximately 5 minutes, i.e. immediately prior to needle insertion until Botulinum toxin (BTX) delivery and needle withdrawal

Clinician's score of overall quality of the EMG signal heard during the procedure. A higher score indicates better quality of EMG signal, and is quantified as 1 to 5, where: 1 indicates signal not present and 5 indicates excellent quality EMG signal.

Outcome measures

Measure	Observation n=25 Participants Participants who were recruited and had their data recorded for this observational study.
Clinical Score of EMG Quality.	4.5 score on a scale Interval 3.0 to 5.0

SECONDARY outcome

Timeframe: 2 weeks

Population: Data was not collected; it was determined before recruitment began that the value of this data did not merit the significant inconvenience to participants of returning for follow-up measurements.

Change in participant's angle of deviation following treatment, measured in prism dioptres.

Outcome measures

Outcome data not reported

Adverse Events

Observation

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Tristan Payne

Medical Physics & Clinical Engineering, Royal Liverpool Hospital

Phone: 0151 7064225

Email: tristan.payne@nhs.net

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place