Category: Tremor
Objective: To explore the features on free hand spirals drawn by patients with essential tremor and essential tremor plus.
Background: The 2018 consensus statement on classification of tremors classifies essential tremor syndromes into essential tremor (ET) and essential tremor plus (ET Plus). It is debated whether ET and ET Plus are distinct manifestations of the same disorder or two different disorders with similar overlapping features. Spiral drawings are used by clinicians worldwide to identify unique patterns in several tremor syndromes. There is very limited data available on spiral signatures of ET and ET Plus.
Method: We recruited 72 patients with upper extremity tremor (ET, n= 16; ETP, n=35; Dystonic Tremor (DT), n=21). Participants drew clockwise spirals on a standard template without supporting their arms on the table. Images were scanned and processed by an in-house developed automated algorithm to compute the mean deviation (MD), tremor variability (TV), intra loop width and inter loop width. Tremor severity was assessed using the Fahn Tolosa Marin Tremor Rating Scale (FTM-TRS). Spiral parameters were compared among the groups DT, ET and ETP.
Results: Mean age of the study population was 47.7±16.1 years (p=0.014). Patients with ET were younger (p=0.014) compared to ET Plus and DT. Mean duration of illness was 9.5±6.7 years, without any significant differences among the groups (p=0.714). FTM-TRS total score was 31.1±14.1, with less severe tremor in ET (p=0.020) compared to the ETP and DT groups. MD [ET: 37.3±17.3, ET Plus: 41.9±21.3, DT: 47.4±22.7; (p=0.343)] and TV [ET: 70.9± 25.0, ET Plus: 70.4± 9.7, DT: 74.8±9.2; (p=0.524)] were similar among the groups. There was no difference in the intraloop widths (F=0.465, p=0.630) and interloop widths (F=0.465, p=0.630) among the groups.
Conclusion: In this cohort, spiral drawing features were similar between ET, ET Plus and DT. Additional features such as spiral axis may be explored in future studies for further characterising the tremor in these syndromes.
To cite this abstract in AMA style:
R. Anandapadmanabhan, A. Vishnoi, A. Latorre, N. Thirugnanasambandam, A. Dipani, D. Biswas, A. Srivastava, K. Bhatia, R. Rajan. Spiral drawing features are similar between essential tremor and essential tremor plus [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/spiral-drawing-features-are-similar-between-essential-tremor-and-essential-tremor-plus/. Accessed May 16, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/spiral-drawing-features-are-similar-between-essential-tremor-and-essential-tremor-plus/