Validation of clinical ratings of cervical dystonia using computer-generated avatars

Sebastian Loens; Roland Stenger; Feline Hamami; Alexander Münchau; Theresa Paulus; Anne Weissbach; Gesine M Sallandt; Tatiana Usnich; Max Borsche; Martje G Pauly; Lara M Lange; Markus A Hobert; Rebecca Herzog; Ana Luísa de Almeida Marcelino; Tina Mainka; Friederike Schumann; Lukas L Goede; Johanna Reimer; Kirsten E Zeuner; Julienne Haas; Jos Becktepe; Alexander Baumann; Robin Wolke; Chi Wang Ip; Thorsten Odorfer; Daniel Zeller; Lisa Harder-Rauschenberger; John-Ih Lee; Philipp Albrecht; Petyo Nikolov; Tristan Kölsche; Joachim K Krauss; Johanna M Nagel; Joachim Runge; Jessica Utermarck; Katja Kollewe; Johanna Doll-Lee; Johanne Heine; Linda Veith Sanches; Simone Zittel; Kai Grimm; Pawel Tacik; André Lee; Andrea Henze; Sebastian Fudickar; Tobias Bäumer

doi:10.1016/j.parkreldis.2025.107975

Validation of clinical ratings of cervical dystonia using computer-generated avatars

Sebastian Loens, Roland Stenger, Feline Hamami, Alexander Münchau, Theresa Paulus, Anne Weissbach, Gesine M Sallandt, Tatiana Usnich, Max Borsche, Martje G Pauly, Lara M Lange, Markus A Hobert, Rebecca Herzog, Ana Luísa de Almeida Marcelino, Tina Mainka, Friederike Schumann, Lukas L Goede, Johanna Reimer, Kirsten E Zeuner, Julienne HaasJos Becktepe, Alexander Baumann, Robin Wolke, Chi Wang Ip, Thorsten Odorfer, Daniel Zeller, Lisa Harder-Rauschenberger, John-Ih Lee, Philipp Albrecht, Petyo Nikolov, Tristan Kölsche, Joachim K Krauss, Johanna M Nagel, Joachim Runge, Jessica Utermarck, Katja Kollewe, Johanna Doll-Lee, Johanne Heine, Linda Veith Sanches, Simone Zittel, Kai Grimm, Pawel Tacik, André Lee, Andrea Henze, Sebastian Fudickar, Tobias Bäumer

Abstract

INTRODUCTION: The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Collum-Caput (Col-Cap) concept are tools for clinically assessing cervical dystonia severity. However, the accuracy of human ratings using these scales has not been systematically evaluated due to the lack of objective reference measurements. This study aims to assess and compare the accuracy of human TWSTRS and Col-Cap ratings to evaluate their robustness for clinical and research applications.

METHODS: One hundred pictures of 26 avatars mimicking cervical dystonia were created using the Rocketbox Avatar library. Forty-one movement disorder specialists rated the head and neck positioning of the avatars using either TWSTRS or Col-Cap. Movements were defined around two rotational levels (head, neck) in three rotational axes (pitch, yaw, roll).

RESULTS: Ratings of angular deviations showed a mean absolute error of 5.8° (SD = 7.0). Rating accuracy was primarily influenced by the magnitude of angular deviation, with larger angles leading to greater estimation errors. Direct comparison of the rating scales revealed a higher accuracy through Col-Cap ratings (71 % vs. 63 % for TWSTRS). Years of clinical experience did not significantly affect rating accuracy.

CONCLUSIONS: Both rating systems (TWSTRS and Col-Cap) show moderate accuracy in assessing head and neck positioning from computer-generated avatars, with Col-Cap showing slightly higher overall accuracy but struggling with precise differentiation between head and neck movements. These findings underscore the limitations of current clinical rating scales and highlight the need for more objective, reliable tools to effectively assess cervical dystonia.

Original language	English
Article number	107975
Journal	Parkinsonism and Related Disorders
Volume	142
Pages (from-to)	107975
ISSN	1353-8020
DOIs	https://doi.org/10.1016/j.parkreldis.2025.107975
Publication status	Published - 01.2026

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Research Areas and Centers

Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)
Research Area: Medical Genetics
Academic Focus: Biomedical Engineering

DFG Research Classification Scheme

2.23-06 Molecular and Cellular Neurology and Neuropathology
4.43-05 Image and Language Processing, Computer Graphics and Visualisation, Human Computer Interaction, Ubiquitous and Wearable Computing

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10.1016/j.parkreldis.2025.107975

Cite this

Loens, S., Stenger, R., Hamami, F., Münchau, A., Paulus, T., Weissbach, A., Sallandt, G. M., Usnich, T., Borsche, M., Pauly, M. G., Lange, L. M., Hobert, M. A., Herzog, R., de Almeida Marcelino, A. L., Mainka, T., Schumann, F., Goede, L. L., Reimer, J., Zeuner, K. E., ... Bäumer, T. (2026). Validation of clinical ratings of cervical dystonia using computer-generated avatars. Parkinsonism and Related Disorders, 142, 107975. Article 107975. https://doi.org/10.1016/j.parkreldis.2025.107975

@article{6a1e1722152d4b25af77ee4f83317340,

title = "Validation of clinical ratings of cervical dystonia using computer-generated avatars",

abstract = "INTRODUCTION: The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Collum-Caput (Col-Cap) concept are tools for clinically assessing cervical dystonia severity. However, the accuracy of human ratings using these scales has not been systematically evaluated due to the lack of objective reference measurements. This study aims to assess and compare the accuracy of human TWSTRS and Col-Cap ratings to evaluate their robustness for clinical and research applications.METHODS: One hundred pictures of 26 avatars mimicking cervical dystonia were created using the Rocketbox Avatar library. Forty-one movement disorder specialists rated the head and neck positioning of the avatars using either TWSTRS or Col-Cap. Movements were defined around two rotational levels (head, neck) in three rotational axes (pitch, yaw, roll).RESULTS: Ratings of angular deviations showed a mean absolute error of 5.8° (SD = 7.0). Rating accuracy was primarily influenced by the magnitude of angular deviation, with larger angles leading to greater estimation errors. Direct comparison of the rating scales revealed a higher accuracy through Col-Cap ratings (71 \% vs. 63 \% for TWSTRS). Years of clinical experience did not significantly affect rating accuracy.CONCLUSIONS: Both rating systems (TWSTRS and Col-Cap) show moderate accuracy in assessing head and neck positioning from computer-generated avatars, with Col-Cap showing slightly higher overall accuracy but struggling with precise differentiation between head and neck movements. These findings underscore the limitations of current clinical rating scales and highlight the need for more objective, reliable tools to effectively assess cervical dystonia.",

author = "Sebastian Loens and Roland Stenger and Feline Hamami and Alexander M{\"u}nchau and Theresa Paulus and Anne Weissbach and Sallandt, \{Gesine M\} and Tatiana Usnich and Max Borsche and Pauly, \{Martje G\} and Lange, \{Lara M\} and Hobert, \{Markus A\} and Rebecca Herzog and \{de Almeida Marcelino\}, \{Ana Lu{\'i}sa\} and Tina Mainka and Friederike Schumann and Goede, \{Lukas L\} and Johanna Reimer and Zeuner, \{Kirsten E\} and Julienne Haas and Jos Becktepe and Alexander Baumann and Robin Wolke and Ip, \{Chi Wang\} and Thorsten Odorfer and Daniel Zeller and Lisa Harder-Rauschenberger and John-Ih Lee and Philipp Albrecht and Petyo Nikolov and Tristan K{\"o}lsche and Krauss, \{Joachim K\} and Nagel, \{Johanna M\} and Joachim Runge and Jessica Utermarck and Katja Kollewe and Johanna Doll-Lee and Johanne Heine and Sanches, \{Linda Veith\} and Simone Zittel and Kai Grimm and Pawel Tacik and Andr{\'e} Lee and Andrea Henze and Sebastian Fudickar and Tobias B{\"a}umer",

year = "2026",

month = jan,

doi = "10.1016/j.parkreldis.2025.107975",

language = "English",

volume = "142",

pages = "107975",

journal = "Parkinsonism and Related Disorders",

issn = "1353-8020",

publisher = "Elsevier Ltd",

}

Loens, S, Stenger, R, Hamami, F, Münchau, A , Paulus, T , Weissbach, A, Sallandt, GM, Usnich, T, Borsche, M , Pauly, MG , Lange, LM , Hobert, MA , Herzog, R, de Almeida Marcelino, AL, Mainka, T, Schumann, F, Goede, LL, Reimer, J, Zeuner, KE, Haas, J, Becktepe, J, Baumann, A, Wolke, R, Ip, CW, Odorfer, T, Zeller, D, Harder-Rauschenberger, L, Lee, J-I, Albrecht, P, Nikolov, P, Kölsche, T, Krauss, JK, Nagel, JM, Runge, J, Utermarck, J, Kollewe, K, Doll-Lee, J, Heine, J, Sanches, LV, Zittel, S, Grimm, K, Tacik, P, Lee, A, Henze, A, Fudickar, S & Bäumer, T 2026, 'Validation of clinical ratings of cervical dystonia using computer-generated avatars', Parkinsonism and Related Disorders, vol. 142, 107975, pp. 107975. https://doi.org/10.1016/j.parkreldis.2025.107975

TY - JOUR

T1 - Validation of clinical ratings of cervical dystonia using computer-generated avatars

AU - Loens, Sebastian

AU - Stenger, Roland

AU - Hamami, Feline

AU - Münchau, Alexander

AU - Paulus, Theresa

AU - Weissbach, Anne

AU - Sallandt, Gesine M

AU - Usnich, Tatiana

AU - Borsche, Max

AU - Pauly, Martje G

AU - Lange, Lara M

AU - Hobert, Markus A

AU - Herzog, Rebecca

AU - de Almeida Marcelino, Ana Luísa

AU - Mainka, Tina

AU - Schumann, Friederike

AU - Goede, Lukas L

AU - Reimer, Johanna

AU - Zeuner, Kirsten E

AU - Haas, Julienne

AU - Becktepe, Jos

AU - Baumann, Alexander

AU - Wolke, Robin

AU - Ip, Chi Wang

AU - Odorfer, Thorsten

AU - Zeller, Daniel

AU - Harder-Rauschenberger, Lisa

AU - Lee, John-Ih

AU - Albrecht, Philipp

AU - Nikolov, Petyo

AU - Kölsche, Tristan

AU - Krauss, Joachim K

AU - Nagel, Johanna M

AU - Runge, Joachim

AU - Utermarck, Jessica

AU - Kollewe, Katja

AU - Doll-Lee, Johanna

AU - Heine, Johanne

AU - Sanches, Linda Veith

AU - Zittel, Simone

AU - Grimm, Kai

AU - Tacik, Pawel

AU - Lee, André

AU - Henze, Andrea

AU - Fudickar, Sebastian

AU - Bäumer, Tobias

PY - 2026/1

Y1 - 2026/1

N2 - INTRODUCTION: The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Collum-Caput (Col-Cap) concept are tools for clinically assessing cervical dystonia severity. However, the accuracy of human ratings using these scales has not been systematically evaluated due to the lack of objective reference measurements. This study aims to assess and compare the accuracy of human TWSTRS and Col-Cap ratings to evaluate their robustness for clinical and research applications.METHODS: One hundred pictures of 26 avatars mimicking cervical dystonia were created using the Rocketbox Avatar library. Forty-one movement disorder specialists rated the head and neck positioning of the avatars using either TWSTRS or Col-Cap. Movements were defined around two rotational levels (head, neck) in three rotational axes (pitch, yaw, roll).RESULTS: Ratings of angular deviations showed a mean absolute error of 5.8° (SD = 7.0). Rating accuracy was primarily influenced by the magnitude of angular deviation, with larger angles leading to greater estimation errors. Direct comparison of the rating scales revealed a higher accuracy through Col-Cap ratings (71 % vs. 63 % for TWSTRS). Years of clinical experience did not significantly affect rating accuracy.CONCLUSIONS: Both rating systems (TWSTRS and Col-Cap) show moderate accuracy in assessing head and neck positioning from computer-generated avatars, with Col-Cap showing slightly higher overall accuracy but struggling with precise differentiation between head and neck movements. These findings underscore the limitations of current clinical rating scales and highlight the need for more objective, reliable tools to effectively assess cervical dystonia.

AB - INTRODUCTION: The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and the Collum-Caput (Col-Cap) concept are tools for clinically assessing cervical dystonia severity. However, the accuracy of human ratings using these scales has not been systematically evaluated due to the lack of objective reference measurements. This study aims to assess and compare the accuracy of human TWSTRS and Col-Cap ratings to evaluate their robustness for clinical and research applications.METHODS: One hundred pictures of 26 avatars mimicking cervical dystonia were created using the Rocketbox Avatar library. Forty-one movement disorder specialists rated the head and neck positioning of the avatars using either TWSTRS or Col-Cap. Movements were defined around two rotational levels (head, neck) in three rotational axes (pitch, yaw, roll).RESULTS: Ratings of angular deviations showed a mean absolute error of 5.8° (SD = 7.0). Rating accuracy was primarily influenced by the magnitude of angular deviation, with larger angles leading to greater estimation errors. Direct comparison of the rating scales revealed a higher accuracy through Col-Cap ratings (71 % vs. 63 % for TWSTRS). Years of clinical experience did not significantly affect rating accuracy.CONCLUSIONS: Both rating systems (TWSTRS and Col-Cap) show moderate accuracy in assessing head and neck positioning from computer-generated avatars, with Col-Cap showing slightly higher overall accuracy but struggling with precise differentiation between head and neck movements. These findings underscore the limitations of current clinical rating scales and highlight the need for more objective, reliable tools to effectively assess cervical dystonia.

UR - https://www.scopus.com/pages/publications/105012217664

UR - https://www.mendeley.com/catalogue/aeeb502d-4559-328e-8753-f7cc3737d8c7/

U2 - 10.1016/j.parkreldis.2025.107975

DO - 10.1016/j.parkreldis.2025.107975

M3 - Journal articles

C2 - 40750554

SN - 1353-8020

VL - 142

SP - 107975

JO - Parkinsonism and Related Disorders

JF - Parkinsonism and Related Disorders

M1 - 107975

ER -

Validation of clinical ratings of cervical dystonia using computer-generated avatars

Abstract

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