Inertial Gait Sensors to Measure Mobility and Functioning in Hereditary Spastic Paraplegia

Abstract

Background and objectives:Hereditary spastic paraplegia (HSP) causes progressive spasticity and weakness of the lower limbs. As neurological examination and the clinical Spastic Paraplegia Rating Scale (SPRS) are subject to potential patient- and clinician-dependent bias, instrumented gait analysis bears the potential to objectively quantify impaired gait. The aim of the present study was to investigate gait cyclicity parameters by application of a mobile gait analysis system in a cross sectional cohort of HSP patients and a longitudinal fast progressing subcohort.Methods:Using wearable sensors attached to the shoes, HSP patients and controls performed a 4x10 meters walking test during regular visits in three outpatient centers. Patients were also rated according to the SPRS and in a subset, questionnaires on quality of life and fear of falling were obtained. An unsupervised segmentation algorithm was employed to extract stride parameters and respective coefficients of variation.Results:Mobile gait analysis was performed in a total of 112 ambulatory HSP patients and 112 age and gender matched controls. While swing time was unchanged compared to controls, there were significant increases in the duration of the total stride phase and the duration of the stance phase, both regarding absolute values and coefficients of variation values. While stride parameters did not correlate to age, weight or height of the patients, there were significant associations of absolute stride parameters to single SPRS items reflecting impaired mobility (|r| > 0.50), to patients’ quality of life (|r| > 0.44), and notably to disease duration (|r| > 0.27). Sensor-derived coefficients of variation, on the other hand, were associated with patient-reported fear of falling (|r| > 0.41) and cognitive impairment (|r| > 0.40). In a small 1-year follow-up analysis of patients with complicated HSP and fast progression, absolute values of mobile gait parameters had significantly worsened compared to baseline.Discussion:The presented wearable sensor system provides parameters of stride characteristics which appear clinically valid to reflect gait impairment in HSP. Due to the feasibility with regard to time, space and costs, the present study forms the basis for larger scale longitudinal and interventional studies in HSP.

Digital gait outcomes for ARSACS: discriminative, convergent and ecological validity in a multi-center study (PROSPAX)

“…We identified 14 measures discriminating ARSACS patients from HC with large effect sizes (|δ| > 0.8), with the top three measures – Lateral Step Deviation, SPcmp and Swing CV – all capturing aspects of spatiotemporal stride variability. This finding corroborates and extends previous studies, demonstrating that measures of spatiotemporal stride variability are increased in ataxia, with effect sizes similar to those observed in this study (6, 7, 30); and – with, however only one study ever reported so far – also in HSP (11). Here, we demonstrate the discriminative validity of these measures the first time for ARSACS, a particular multisystemic disease combining not only ataxia and HSP features, but also severe neuropathy.…”

“…Digital gait outcomes obtained through wearable sensors have shown promising results in other genetic ataxias, with several cross-sectional studies demonstrating reliable discrimination between patients and controls, and correlation with clinical measures of disease severity(6–8); and first longitudinal studies also demonstrating sensitivity to change(5, 9). In contrast, wearable sensor-based gait studies are still scarce in hereditary spastic paraplegias (HSPs)(10, 11), and no genotype-specific studies on sensor-based gait measures have been conducted in spastic ataxias, let alone in spastic ataxias with prominent multi-systemic involvement like ARSACS. Moreover, multi-center studies – as inevitably required for trials in such rare diseases – are very scarce in ataxias(7) and HSPs, demonstrating the urgent need for multi-center validation of performance and outcome validity.…”

Mobile digital gait analysis objectively measures progression in hereditary spastic paraplegia

“…Moreover, gait variability was significantly associated with changes in mental health functioning as measured by the SF-12 mental component score. In conjunction with the previously reported application of the present mobile gait analysis system in a cross-sectional multicenter HSP cohort, 16 the present study paves the ground for future application of mobile gait analysis in interventional studies, genotype specific natural history studies, and in the patients' home environments.…”

“…Mobile gait analysis was performed during a 4 × 10 m walking test. Gait cyclicity parameters (stride time, stance time, and swing duration) and their respective coefficient of variation (CV) values were obtained as previously described 16 . In addition, we measured the times to complete the first 10 m and to complete the Timed Up and Go test (TUG) 20 .…”

“…14,15 Using this system in a large multi-center study of HSP patients, we showed that gait cyclicity measures correlated with SPRS mobility subitems and the self-rated fear of falling and quality of life. 16 The aims of this study were (1) to investigate whether gait parameters, clinical scores, and self-rating questionnaires change in a defined longitudinal HSP cohort over time, (2) to analyze correlations between changes in gait parameters and SPRS, and (3) to explore which gait parameters most suitably reflect HSP progression or correlate best to longitudinal changes of SPRS clinical subitems. 3 years AE 3 months: exclusion of 29 patients).…”