Quantitative assessment of cerebellar ataxia, through automated limb functional tests

Abstract

Background Cerebellar damage can often result in disabilities affecting the peripheral regions of the body. These include poor and inaccurate coordination, tremors and irregular movements that often manifest as disorders associated with balance, gait and speech. The severity assessment of Cerebellar ataxia (CA) is determined by expert opinion and is likely to be subjective in nature. This paper investigates automated versions of three commonly used tests: Finger to Nose test (FNT), test for upper limb Dysdiadochokinesia Test (DDK) and Heel to Shin Test (HST), in evaluating disability due to CA. Methods Limb movements associated with these tests are measured using Inertial Measurement Units (IMU) to capture the disability. Kinematic parameters such as acceleration, velocity and angle are considered in both time and frequency domain in three orthogonal axes to obtain relevant disability related information. The collective dominance in the data distributions of the underlying features were observed though the Principal Component Analysis (PCA). The dominant features were combined to substantiate the correlation with the expert clinical assessments through Linear Discriminant Analysis. Here, the Pearson correlation is used to examine the relationship between the objective assessments and the expert clinical scores while the performance was also verified by means of cross validation. Results The experimental results show that acceleration is a major feature in DDK and HST, whereas rotation is the main feature responsible for classification in FNT. Combining the features enhanced the correlations in each domain. The subject data was classified based on the severity information based on expert clinical scores. Conclusion For the predominantly translational movement in the upper limb FNT, the rotation captures disability and for the DDK test with predominantly rotational movements, the linear acceleration captures the disability but cannot be extended to the lower limb HST. The orthogonal direction manifestation of ataxia attributed to sensory measurements was determined for each test. Trial registration Human Research and Ethics Committee, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia (HREC Reference Number: 11/994H/16). Electronic supplementary material The online version of this article (10.1186/s12984-019-0490-3) contains supplementary material, which is available to authorized users.

A Comprehensive Scheme for the Objective Upper Body Assessments of Subjects with Cerebellar Ataxia

“…Measures pertaining to this axis can be used to infer the decits in rhythmicity or timing. In the frequency analysis, timing aspects or "how quick is the movement performed" were described by the RF, whereas MR indicated the intensity of the rhythmic movement [13] which was considered as a measure of rhythmicity.…”

“…As recognised by pioneering clinicians such as Holmes [5,6] [12] without the requirement of sophisticated and often complex infrastructure. IMU based systems were also used eectively in FNT [13,14] and DDKT [13] where the axes of movement characterising ataxia were captured, monitored and evaluated. The movement of the nger performing the FCT has been tracked using optoelectronic devices ranging from video cameras [15] to VICON [16] and recently Kinect © in our previous study [4] to assess delay in initiating movement and accuracy in reaching the target.…”

“…, the angular accelerations and linear accelerations can be used to characterise ataxia[13] more eectively. The RF and MR of angular accelerations in the three axes were calculated as well as the linear acceleration in the X axis.…”

“…Only RF was applied to the linear acceleration in the Y and Z axes. In the case of the DDKT, RF and MR of angular acceleration and linear accelerations accelerations in all axes best distinguished between ataxics and controls[13]. To overcome this and improve the prediction power the number of features were reduced using feature selection (FS) techniques.…”

Assessment and Rating of Motor Cerebellar Ataxias With the Kinect v2 Depth Sensor: Extending Our Appraisal

“…Each study confined its point of evaluation to only one part of the body, such as the forelimb [e.g., (5-8, 12, 19)] or gait [e.g., (9)(10)(11)]. Since these studies were not designed to make comprehensive (20). In other words, they evaluated parameters that were not compatible with SARA.…”