Official Title

Effects of Octanoic Acid for Treatment of Essential Voice Tremor
  • Phase

    Phase 1/Phase 2
  • Study Type

    Interventional
  • Intervention/Treatment

    octanoic acid ...
  • Study Participants

    17
Essential voice tremor is a neurological condition that produces a regular, shaking quality in the voice. One form of drug treatment that produces some improvement in tremor of the hands is octanoic acid, which is a food additive that is similar to alcohol. Research suggests that octanoic acid may reduce tremor in the hands/arms with few side effects and no intoxication effects. This study will determine whether octanoic acid may be useful for reducing tremor when it affects the voice. Researchers are hypothesizing that octanoic acid will reduce the effects of tremor on the voice.
Background:

Essential tremor of the voice produces regular shaking and hoarseness in the voice, making it difficult speech difficult to understand
Several previous studies have found that octanoic acid and octanol, which are related to alcohol, can improve tremor in some people without producing many side effects and without producing intoxication
Researchers are interested in determining whether octanoic acid can improve tremor that affects the voice

Objectives:

To determine the effects of octanoic voice using voice recordings and listener ratings of voice
To determine the effects of octanoic acid on level of voice disability experienced by people with essential voice tremor
Study Started
Jul 31
2013
Primary Completion
Dec 22
2016
Study Completion
Mar 31
2017
Results Posted
Aug 20
2018
Last Update
Aug 20
2018

Drug Octanoic acid

  • Other names: Caprylic acid

Drug Inactive capsule

  • Other names: Placebo

Inactive capsule Placebo Comparator

Participants will receive a pill/capsule with an inactive ingredient during the placebo arm of this study.

Octanoic acid Experimental

Participants will receive a pill/capsule with octanoic acid (amount determined by the participant's weight) during the experimental arm of this study.

Criteria

Inclusion Criteria:

Participants have a diagnosis of essential voice tremor and show signs of tremor during the endoscopy examination (when pictures of the voice box are obtained)during screening appointment
Participants show measurable voice tremor from recordings of the voice during screening appointment

Exclusion Criteria:

Participants have a diagnosis or show signs of Parkinson's Disease or another non-essential tremor movement disorder
Participants have a diagnosis or show signs of spasmodic dysphonia (a different neurological voice disorder)
Participants have a diagnosis of a severe, non-stable medical condition, such as kidney or liver failure, severe heart disease, severe lung disease, severe metabolic disease, uncontrolled hyperthyroidism, or other life-threatening disease such as active cancer
Participants have a diagnosis of diabetes mellitus
Participants are unable to suspend/stop a medication that they are currently taking for tremor or voice disorder for 12 weeks to complete this study
Participants have a dependence on alcohol or allergy to alcohol
Participants are pregnant or lactating
Participants have an allergy to soy
Participants have Irritable Bowel Syndrome

Summary

Placebo

Octanoic Acid

All Events

Event Type Organ System Event Term Placebo Octanoic Acid

Magnitude of Acoustic Amplitude Tremor and Magnitude of Acoustic Frequency Tremor

Voice recordings were used to measure the degree of tremor in the voice. Mean post-test values for each acoustic measure were compared after the octanoic acid and placebo conditions, with and without consideration of baseline values. Mean values represent the average of two testing days. Degree of amplitude tremor shows the extent of amplitude variation as a percent of the mean signal amplitude, with lower numbers indicating less amplitude tremor. Baseline values for magnitude of amplitude tremor across all participants and conditions ranged from 4.06 to 27.09, and post-test values ranged from 1.94 to 26.02. Degree of frequency tremor shows the extent of fundamental frequency variation as a percent of the mean signal frequency, with lower numbers indicating less frequency tremor. Baseline values for magnitude of frequency tremor across all participants and conditions ranged from 1.21 to 15.31, and post-test values ranged from 0.60 to 13.86.

Placebo

Baseline Magnitude of Acoustic Amplitude Tremor

12.91
percentage of voice signal with tremor (Mean)
Standard Deviation: 6.46

Baseline Magnitude of Acoustic Frequency Tremor

5.57
percentage of voice signal with tremor (Mean)
Standard Deviation: 4.29

Post-test Magnitude of Acoustic Amplitude Tremor

12.43
percentage of voice signal with tremor (Mean)
Standard Deviation: 7.37

Post-test Magnitude of Acoustic Frequency Tremor

5.35
percentage of voice signal with tremor (Mean)
Standard Deviation: 3.76

Octanoic Acid

Baseline Magnitude of Acoustic Amplitude Tremor

13.49
percentage of voice signal with tremor (Mean)
Standard Deviation: 6.48

Baseline Magnitude of Acoustic Frequency Tremor

5.19
percentage of voice signal with tremor (Mean)
Standard Deviation: 3.58

Post-test Magnitude of Acoustic Amplitude Tremor

9.35
percentage of voice signal with tremor (Mean)
Standard Deviation: 5.42

Post-test Magnitude of Acoustic Frequency Tremor

3.98
percentage of voice signal with tremor (Mean)
Standard Deviation: 2.94

Auditory-perceptual Tremor Severity Ratings

Three experienced listeners independently rated each participant's voice from paired sample recordings comparing the baseline to post-test samples in randomized order for each condition. Sustained vowel and sentence-level recordings were rated, with decoded samples later analyzed for 1=better for post-test compared to baseline, 0= no difference between post-test and baseline. Maximum score for each participant was 3 (post-test was better for each of three raters). The range of possible scores was the sum of each of three raters' scores (0 to 3), with 0 indicating no difference between baseline and post-test voice tremor severity rating, and 3 indicating better voice (less tremor severity) at post-testing compared to pre-testing. Mean post-test values for task were compared for the octanoic acid and placebo conditions, and all raters were blind to which sample was a baseline versus a post-test recording, and which samples were associated with the [placebo or octanoic acid conditions.

Placebo

Sentence-level, summed binary ratings (0-3)

1.63
units on a scale (Mean)
Standard Deviation: 1.12

Sustained vowel, summed binary ratings (0-3)

1.25
units on a scale (Mean)
Standard Deviation: 1.13

Octanoic Acid

Sentence-level, summed binary ratings (0-3)

1.19
units on a scale (Mean)
Standard Deviation: 0.87

Sustained vowel, summed binary ratings (0-3)

1.53
units on a scale (Mean)
Standard Deviation: 1.13

Total

17
Participants

Age, Continuous

69.53
years (Mean)
Standard Deviation: 9.01

Ethnicity (NIH/OMB)

Race (NIH/OMB)

Sex: Female, Male

Overall Study

Inactive Capsule First

Octanoic Acid First

Drop/Withdrawal Reasons

Inactive Capsule First