Jul 10, 2025
Effect of Tetrabenazine on Stroop Interference in Huntington’s Disease
- Robert Fekete, M.D.1
- 1Department of Neurology, New York Medical College, United States of America
- Dr. Robert Fekete
External link: https://doi.org/10.21203/rs.3.rs-6755188/v1
Protocol Citation: Robert Fekete, M.D. 2025. Effect of Tetrabenazine on Stroop Interference in Huntington’s Disease. protocols.io https://dx.doi.org/10.17504/protocols.io.e6nvw4647lmk/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: July 10, 2025
Last Modified: July 10, 2025
Protocol Integer ID: 222162
Keywords: Huntington’s disease, tetrabenazine, Stroop test, Stroop interference, stroop interference in huntington, effect of partial dopaminergic depletion, effect of tetrabenazine, tetrabenazine withdrawal study in patient, tetrabenazine withdrawal study, partial dopaminergic depletion, interfering visual stimuli, stroop interference score, stroop interference, huntington, interference, visual stimuli
Abstract
The protocol describes a tetrabenazine withdrawal study in patients with Huntington's disease which aims to understand the effect of partial dopaminergic depletion on masking out interfering visual stimuli. ON and OFF Stroop interference scores are measured. Golden's formula to calculate Stroop interference will be used.
Image Attribution
Image was created by ChatGPT OpenAI GPT-4o mini on 7/9/2025 at the following link
Guidelines
Researchers will adhere to all safety and training protocols required by the New York Medical College including but not limited to:
Collaborative Institutional Training Initiative (CITI program) certification
Materials
Subjects who are nursing home residents nursing home and have an established diagnosis of Huntington disease will be recruited by the principal investigator for participation in this study. Written informed consent will be obtained from the subjects and also from next of kin given cognitive disturbance in HD.
Troubleshooting
Safety warnings
Side effect warnings of tetrabenazine listed in Prescribing Information apply.
Ethics statement
The study was registered at the National Institutes of Health Protocol Registration and Results system as NCT01834911 on April 15th, 2013. The study was approved by the New York Medical College Office of Research Administration Institutional Review Board under tracking number L-10,830. There was no funding support for the trial.
Methods
Stroop test was administered to patients in the morning to patients who are off tetrabenazine (de novo or three-day withdrawal). 12.5 mg of TBZ will be administered just after the first Stroop test and also 3 hours later. On Stroop test was to be administered 6 hours after the off Stroop test. The raw Stroop word reading, color reading, and interference scores were recorded and used for further analysis.
Inclusion Criteria
Study specific Inclusion Criteria
1. Established diagnosis of Huntington disease by movement disorders expert
2. Patients not currently taking tetrabenazine as well as those off tetrabenazine for at
least three days
3. Patients should not have taken dopamine receptor blocking medication for at least three
days (as this has been shown to affect the Stroop score in normals).
Citation
LINK
Protocol
2m 15s
Patient in OFF tetrabenazine state
Utilize official Stroop test booklet
Citation
LINK
00:00:45 Administer Stroop Word test and obtain W raw score
45s
00:00:45 Administer Stroop Color test and obtain C raw score
45s
00:00:45 Administer Stroop Color-Word test and obtain CW raw score
45s
Calculate interference score using formula
Interference score = CW − [(W × C)/(W + C)]
where C, W, and CW correspond to raw scores
Citation
LINK
Patient in ON tetrabenazine state
Utilize official Stroop test booklet
Citation
LINK
00:00:45 Administer Stroop Word test and obtain W raw score
00:00:45 Administer Stroop Color test and obtain C raw score
00:00:45 Administer Stroop Color-Word test and obtain CW raw score
Calculate interference score using formula
Interference score = CW − [(W × C)/(W + C)]
where C, W, and CW correspond to raw scores
Citation
LINK
Proposed statistical analysis
Given that a study examining effect on Stroop scores in
the setting of low dose tetrabenazine administration has not been previously
performed, the size of the potential effect is not known and hence direct power
analysis is not possible.
The closest study from which to obtain effect size on
Stroop test for power analysis is a three day withdrawal of steady state tetrabenazine.
Citation
LINK
Using Glass’s delta formula:
delta = | averagea- averageb | / stdevcontrol
delta = |14.3-7.72| / 7.5 = 0.8773
alpha=0.05 for single tailed t test power=1-beta
error=0.95 with sample size of 8 as calculated by G Power software.
Citation
LINK
Protocol references
Fekete R, Davidson, A, Cohen HS, Ondo WG. Effects of tetrabenazine on computerized dynamic posturography in Huntington disease patients. Park Rel Dis Epub: May 2012 doi:10.1016/j.parkreldis.2012.04.029
Williams JH, Wellman NA, Geaney DP, et al. Haloperidol reduces Stroop interference and increases negative priming in healthy people. Schizophr Res 1996, 18, 223.
Fekete R, Davidson A, Jankovic J. Clinical assessment of the effectof tetrabenazine on functional scales in Huntington disease: a pilot open label study. Tremor Other Hyperkinet Mov 2012, 2, http://tremorjournal.org/article/view/86
Faul F, Erdfelder E., Lang,AG, Buchner A. G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods. 2007, 39, 175-91.
Citations
Step 2.3
Williams JH, Wellman NA, Geaney DP, Cowen PJ, Feldon J, Rawlins JNP. . Haloperidol reduces Stroop interference and increases negative priming in healthy people.
https://doi.org/10.1016/0920-9964(96)85686-6Step 3
Golden C, Freshwater SM, Golden Z. Stroop Color and Word Test
https://doi.org/10.1037/t06065-000Step 3.4
Scarpina F, Tagini S. The Stroop Color and Word Test.
https://doi.org/10.3389/fpsyg.2017.00557Step 4
Golden C, Freshwater SM, Golden Z. Stroop Color and Word Test
https://doi.org/10.1037/t06065-000Step 4.4
Scarpina F, Tagini S. The Stroop Color and Word Test.
https://doi.org/10.3389/fpsyg.2017.00557Step 5
Fekete R, Davidson A, Jankovic J. Clinical assessment of the effect of tetrabenazine on functional scales in huntington disease: a pilot open label study.
https://doi.org/pii:tre-02-86-476-4.10.7916/D8DN43SCStep 5
Faul F, Erdfelder E., Lang,AG, Buchner A.. G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences.
https://doi.org/10.3758/bf03193146