Computer-based assessment of upper-limb incoordination in autosomal recessive spastic ataxia of Charlevoix-Saguenay patients: A pilot study Hung Tien Bui a,c , Olivier Audet d , Jean Mathieu b,c , Cynthia Gagnon b,c,e , Mario Leone a,c, ⁎ a Université du Québec à Chicoutimi, Canada b Université de Sherbrooke, Canada c Groupe de recherche interdisciplinaire sur les maladies neuromusculaires, Centre intégré universitaire de santé et de services sociaux du Saguenay-Lac-St-Jean, Canada d Université Laval, Canada e Centre de recherche Charles-Le-Moyne, Canada abstract article info Article history: Received 14 December 2016 Received in revised form 12 June 2017 Accepted 7 July 2017 Available online 09 July 2017 Ataxia refers to a group of neurological disorders characterized by a lack of coordination during voluntary move- ments. One of the most commonly used tests to assess upper-limb coordination is the Archimedes spiral test. The purpose of this research is to present an innovative computer-based Archimedes spiral test that can accurately assess coordination. Forty nine individuals (age: 25.2 ± 7.1 years) were recruited including thirteen patients di- agnosed with Autosomal Recessive Spastic Ataxia of Charlevoix/Saguenay (ARSACS). Participants were instructed to trace a spiral on the touch-screen with the tip of their index finger at a self-paced velocity by following an on- screen spiral template. Mean error and maximum error as well as frequency analysis were calculated to classify healthy and ARSACS participants. While mean and maximum errors provided good results, the highest classifica- tion success rate was obtained using frequency analysis, particularly between f = 1.2 Hz and f = 1.7 Hz. Interpre- tation of traditional paper-drawn Archimedes spirals is limited, and several computerized versions have been reported. Herein, we present a custom-made tool that allows discrimination of measures assessing ataxia in ARSACS. This utilizes a proposed frequency method that may have the potential to track the evolution of upper-limb incoordination in patients and therefore help clinicians and scientists to better monitor their patients. © 2017 Elsevier B.V. All rights reserved. Keywords: Ataxia Coordination Computer-based system Upper-limbs Frequency analysis Outcome measure 1. Introduction Recessive ataxias are a heterogeneous group of neurodegenerative disorders affecting the cerebellum and/or the spinal cord. Autosomal re- cessive spastic ataxia of Charlevoix/Saguenay (ARSACS) falls into this family of neurological diseases [1]. This particular neurological condi- tion was first described by Bouchard and colleagues in 1978 [2]. Clinical- ly, ARSACS is a mixed picture of progressive upper motor neuron, cerebellar and peripheral neuropathy with variable intensity of these three components [3]. The progressive loss of coordination in the upper limbs is a key feature of the disease [4]. The assessment of coordi- nation is greatly influenced by the presence of the peripheral neuropa- thy where a progressive loss of strength is clinically observed in the thumb abductor and the intrinsic muscles of the hand. It often limits the choice of assessment methods as most of them imply some type of fine prehension. A common test for assessing upper-limb incoordina- tion is the Archimedes spiral [5,6]. This test has been established to show quantitative changes in essential tremor, Parkinson Disease, Niemann-Pick disease, psychogenic movement disorders and ataxia [5,7–10]. 1.1. The Archimedes spiral test There are several ways of performing the Archimedes spiral test. The standard Archimedes spiral test used in neurology consists of drawing a free form spiral [11]. Another method proposes drawing between two standardized spiral lines [12]. Finally, the method used in this paper consists in tracing over a standardized spiral [13–16] In its original form, the spiral is traced using pen and the result is analyzed qualita- tively to classify the participant in one of five possible levels ranging from 0 to 4 [17]. In addition, it is also possible to measure the deviations between the standardized shape and the drawn spiral by using a ruler. A participant's coordination can then be evaluated according to the num- ber and magnitude of these deviations. However, this method has limi- tations: the use a standard ruler only allows for limited accuracy of the measurement and the evaluation of the spiral trace only considers the sections containing the largest errors and thus, provides an incomplete picture. Although this procedure is regularly used in the evaluation of several ataxic syndromes and other movement disorders, the level of Journal of the Neurological Sciences 380 (2017) 68–73 ⁎ Corresponding author at: Département des Sciences de la santé, Programmes de kinésiologie, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Saguenay, Québec G7H 2B1, Canada. E-mail address: mario.leone@uqac.ca (M. Leone). http://dx.doi.org/10.1016/j.jns.2017.07.013 0022-510X/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns