The Association of Tremor and Clinical Measures in Persons with Multiple Sclerosis Utilizing the Movalyzer® Software

Background: Tremor, a symptom of MS, is prevalent in 45.0-46.8% of NARCOMS registrants. There are many tests used to identify tremor, but only a few objective tests able to quantify and characterize tremor which can be easily performed in a clinical setting. The Archimedes spiral, a common clinical test, in conjunction with a digital tablet and software to analyze the drawing, allows for the collection of an objective measure of tremor severity. The MovAlyzeR^®software may be useful to obtain quantitative variables (MVar) to characterize tremor in persons with Multiple Sclerosis (pwMS). 

Objectives: The objective of this study is to describe the relationship between variables describing tremor, obtained by the MovAlyzeR^® software during a spiral drawing task, and clinical measures in pwMS. 

Methods: Of 267 participants recruited into a larger ongoing study, data on 258 were analyzed. Clinical measures included: Finger to Nose (FTN), Box and Block (BBT), Nine Hole Peg Test (NHPT), Written Archimedes Spiral (WAS), and visually observed tremor (VOT) during FTN. The MVar included: segment rate (SEGRT), absolute velocity (VABS), absolute acceleration (AABS), peak frequency (PFRQ), and peak power (PPWR). Bivariate Correlations of clinical measures and MVar were calculated using Spearman rank order correlation due to non-normality, with a two-tailed test for significance (p<0.05) on the clinical measures and the MVar. SEGRT was analyzed for 258 participants, but other MVar were correlated for 214 participants due to incomplete data.

Results: The following significant correlations were found: SEGRT was negatively correlated with the FTN (r=-0.332) and BBT (r=-0.352), and positively correlated with the NHPT(r=0.362), VOT (r=0.256), and WAS (r=0.210). AABS was negatively correlated with the FTN (r=-0.211) and BBT (r=-0.169), and positively correlated with NHPT (r=0.159), VOT (r=0.166), and WAS (r=0.143). No significant correlation was found between VABS, PFRQ, and PPWR and the clinical measures. 

Conclusions: SEGRT demonstrates a significant, moderate correlation with VOT and increased impairment in FTN, BBT, NHPT, and WAS. These results indicate an increased rate of tremor is correlated with decreased performance in the FTN, BBT, NHPT, and WAS clinical measures. AABS was correlated with FTN, BBT, NHPT, VOT, and WAS which indicates that an increased rate of change in speed in the spiral drawing is correlated with decreased performance in those clinical measures.