Quantitative assessment of cerebella ataxia through automated upper limb functional tests

Neurological disorders typically exhibit movement disabilities and disorders such as cerebellar ataxia (CA) can cause coordination inaccuracies often manifested as disabilities associated with gait, balance and speech. Since the severity assessment of the disorder is based on the expert clinical opinion, it is likely to be subjective. Automated versions of two upper limb tests: Finger to Nose test (FNT) and Diadochokinesia (DDK) test are investigated in this paper. Inertial Measurement Units (IMU) (BioKinTM ) are employed to capture the disability by measuring limb movements. Translational and rotational accelerations considered as kinematic parameters provided the features relevant to characteristic movements intrinsic to the disability. Principal Component Analysis (PCA) and multi-class Linear Discriminant classifier (LDA) were instrumental in dominant features correlating with the clinical scores. The relationship between clinicians assessment and the objective analysis is examined using Pearson Correlation. This study found that although FNT predominantly consist of translational movements, rotation was the dominant feature while for the case of DDK that predominantly consist of rotational movements, acceleration was the dominant feature. The degree of correlation in each test was also enhanced by combining the features in different tests

Swayed by sound: sonic guidance as a neurorehabilitation strategy in the cerebellar ataxias

Cerebellar disease leads to problems in controlling movement. The most common difficulties are dysmetria and instability when standing. Recent understanding of cerebellar function has expanded to include non -motor aspects such as emotional, cognitive and sensory processing. Deficits in the acquisition and processing of sensory information are one explanation for the movement problems observed in cerebellar ataxia. Sensory deficits result in an inability to make predictions about future events; a primary function of the cerebellum. A question therefore, is whether augmenting or replacing sensory information can improve motor performance in cerebellar disease. This question is tested in this thesis by augmenting sensory information through the provision of an auditory movement guide.A variable described in motor control theory (tau) was used to develop auditory guides that were continuous and dynamic. A reaching experiment using healthy individuals showed that the timing of peak velocity, audiomotor coordination accuracy, and velocity of approach, could be altered in line with the movement parameters embedded in the auditory guides. The thesis then investigated the use of these sonic guides in a clinical population with cerebellar disease. Performance on neurorehabilitation exercises for balance control was tested in twenty people with cerebellar atrophy, with and without auditory guides. Results suggested that continuous, predictive, dynamic auditory guidance is an effective way of improving iii movement smoothness in ataxia (as measured by jerk). In addition, generating and swaying with imaginary auditory guides was also found to increase movement smoothness in cerebellar disease.Following the tests of instantaneous effects, the thesis then investigated the longterm consequences on motor behaviour of following a two -month exercise with auditory guide programme. Seven people with cerebellar atrophy were assessed pre - and post -intervention using two measures, weight -shifting and walking. The results of the weight -shifting test indicated that the sonic -guide exercise programme does not initiate long -term changes in motor behaviour. Whilst there were minor, improvements in walking, because of the weight -shifting results, these could not be attributed to the sonic guides. This finding confirms the difficulties of motor rehabilitation in people with cerebellar disease.This thesis contributes original findings to the field of neurorehabilitation by first showing that on -going and predictive stimuli are an appropriate tool for improving motor behaviour. In addition, the thesis is the first of its kind to apply externally presented guides that convey continuous meaningful information within a clinical population. Finally, findings show that sensory augmentation using the auditory domain is an effective way of improving motor coordination in some forms of cerebellar disease

Cognitive-motor interference in people with multiple sclerosis: a kinematic approach to clarify the effect of cognitive load on walking performance

The simultaneous performance of cognitive tasks during locomotion (or cognitive-motor dual-task) is known to cause performance deficits in either one of, or both tasks. Furthermore, these performance decrements are exacerbated by the presence of motor impairments and cognitive dysfunctions characteristic of numerous neurological diseases, such as multiple sclerosis (MS). In this regard the assessment of walking while performing a cognitive task may represent a relevant outcome measure, because it allows measuring, in a laboratory setting, individual’s ability to cope with walking challenging situations similar to everyday living. The first aim of this thesis is to provide an experimental setup, based on the use of optoelectronic stereophotogrammetry, for obtaining quantitative evaluation of walking biomechanics and motor strategies during dual-task performance in both healthy adults and people with MS (pwMS). Then, this experimental methodology is tested as suitable method not only for detecting, measuring and characterizing disability, but also for testing intervention effectiveness in clinical practice. Specifically, the study is focused on the assessment of spatiotemporal parameters and lower limb kinematics during single- (normal pace walking) and dual-task (walking while performing a discrimination and decision-making). This thesis is composed of four experiments. The first two aimed to measure the effect of cognitive-motor interference on walking biomechanics in terms of spatiotemporal parameters and lower limb joint kinematics. In this regard, a sample of pwMS stratified by disability level (low disability, EDSS 1.0-2.5, n=37; mild to moderate disability, EDSS 3.0-6.0, n=44) and a sample of age- and gender-matched healthy adults (n=41) underwent a 3D kinematic evaluation of single- and dual-task performance using a motion capture system. Differences between conditions and groups were investigated using a two-way repeated ANOVA. The results reported that gait speed and stride length were sensitive motor variables in detecting differences from single- to dual-task condition in both pwMS and unaffected individuals, whereas spatiotemporal parameters closely related to balance control (e.g. step width, double support phase duration) were sensitive to changes only in pwMS with moderate disability. Moreover, those patients showed significant changes in the kinematics of distal joint (shank-foot) and proximal joint (hip), including a reduction in ankle plantarflexion and hip extension peak at the terminal stance phase. These observed changes in more impaired patients are compensatory mechanism to stabilize body posture and allow safe locomotion during complicate dual-task activities. Finally, the other two experiments were designed to provide a clinical application of this methodology, as a tool for quantitatively assessing biomechanics changes after an innovative therapeutic intervention. In this regard, a sample of pwMS (n=34) with mild to moderate disability participated in a bicentric clinical trial. As per protocol, pwMS completed an intervention consisting of either active or sham multiple sessions of transcranial direct current stimulation (tDCS) combined with physical activity, aimed to improve walking performance. Following repeated application of active tDCS, the results obtained from the quantitative gait analysis showed greater improvements in gait velocity, step length and walking endurance. This improvement measured in walking had corresponding effects on walking dual-task performance. In fact, the dual-task cost of gait parameters was significantly reduced after the active tDCS intervention. In conclusion, the quantitative assessment of walking impairments during the execution of functional task in pwMS can support a deep learning of both movement features and motor strategies, which should have implications for the design and validation of clinical intervention aimed at improving functional walking

A Logistic Regression Model for Biomechanical Risk Classification in Lifting Tasks

Lifting is one of the most potentially harmful activities for work-related musculoskeletal disorders (WMSDs), due to exposure to biomechanical risk. Risk assessment for work activities that involve lifting loads can be performed through the NIOSH (National Institute of Occupational Safety and Health) method, and specifically the Revised NIOSH Lifting Equation (RNLE). Aim of this work is to explore the feasibility of a logistic regression model fed with time and frequency domains features extracted from signals acquired through one inertial measurement unit (IMU) to classify risk classes associated with lifting activities according to the RNLE. Furthermore, an attempt was made to evaluate which are the most discriminating features relating to the risk classes, and to understand which inertial signals and which axis were the most representative. In a simplified scenario, where only two RNLE variables were altered during lifting tasks performed by 14 healthy adults, inertial signals (linear acceleration and angular velocity) acquired using one IMU placed on the subject's sternum during repeated rhythmic lifting tasks were automatically segmented to extract several features in the time and frequency domains. The logistic regression model fed with significant features showed good results to discriminate "risk" and "no risk" NIOSH classes with an accuracy, sensitivity and specificity equal to 82.8%, 84.8% and 80.9%, respectively. This preliminary work indicated that a logistic regression model-fed with specific inertial features extracted by signals acquired using a single IMU sensor placed on the sternum-is able to discriminate risk classes according to the RNLE in a simplified context, and therefore could be a valid tool to assess the biomechanical risk in an automatic way also in more complex conditions (e.g., real working scenarios)

Bimanual coordination and motor learning in children with unilateral motor disorders

Introduction Appropriate bimanual coordination is essential for many tasks in daily life. Children with unilateral cerebral palsy (uCP) however struggle with the execution of such tasks. Extensive research has been done investigating motor impairments on a functional level using standardized procedures. There is a lack of studies however looking at the specific problem of coordination of a bimanual task, especially with respect to the different underlying neuropathologies. Aims & Methods Within this thesis, kinematics of bimanual hand movement during a role differentiated bimanual box opening task in children with uCP, as well as in typically developing children (TDC) of similar ages, were investigated. The aims were: i) to identify behavioural changes in peak periods of development of the corpus callosum and areas of the prefrontal cortex, both of which are related to bimanual function in typically developing children; ii) to explore the relation between motor impairments of children with uCP and their bimanual coordination and iii) to investigate the impact of various underlying neuropathologies on bimanual coordination in children with uCP. Results For the first study, a total of 37 TDC between 5 and 16 years were included and allocated to their respective age-group: Young Children (YC: 5-6 years), Old Children (OC: 7-9 years) and Adolescents (AD: 10-16 years). The two older groups performed the task significantly faster than YC. Likewise, a trend (yet without reaching significance) towards a more ideal temporal sequencing was shown between YC and the two older groups. In contrast, spatial accuracy as expressed by the path length increased only in the AD group. For the second study, a total of 37 children with uCP between 7 and 17 years were included. Children presented manual impairments between levels I and III (according to the Manual Ability Classification System). It could be shown that task duration increased and spatial accuracy decreased with increasing levels of impairment, especially in children with higher levels of impairment (level III). Furthermore it could be shown that a subgroup of children experienced an involuntary interference when moving their affected hand, limiting the use of their less affected hand. The third study utilised a multiple case study involving nine children diagnosed with uCP with neuroimaging and neurophysiological data. The children were found to have various neuropathological patterns resulting in different forms and severities of motor impairments. It could be shown that grey-matter lesions had the most severe impact on manual abilities. Conclusion In TDC, performance of bimanual hand movements was temporally related to peak developmental periods of the corpus callosum, emphasizing the importance of interhemispheric exchange of information for bimanual coordination. In children with uCP, bimanual performance was related to the level of impairment of the affected hand. In addition it was found however that some children show excessive bimanual interference when using their affected hand in a bimanual task which limits the functionality of the less affected hand, possibly related to i) ipsilateral corticomotor projection patterns from the less affected hemisphere to the affected hand or ii) lack of suppression of interhemispheric crosstalk. It could also be shown that the various neuropathologies can affect bimanual motor control differently. Detailed diagnosis of the neuropathology and motor impairment are thus essential for the planning of tailored therapy interventions

Kinematická analýza rytmických pohybů: aplikace na třes rukou člověka a kmit křídel mušky octomilky.

Rytmický pohyb, pravidelný nebo nepravidelný, je nedílnou součástí motorického chování a to jak ve zdraví, tak v průběhu nemoci. Hlubší pochopení geneze rytmického pohybu je důležité pro porozumění patofyziologii onemocnění, mezi jejichž projevy rytmický pohyb patří. V disertační práci jsem studovala dva konkrétní aspekty rytmického pohybu: bilaterální koordinaci a modulární řízení. První z nich jsem analyzovala na třesu lidských rukou, druhý na pohybu křídel u modelového organismu Drosophila melanogaster (octomilka obecná). Mnoho typů třesu, včetně fyziologického třesu (PT) a esenciálního tremoru (ET), se vyskytuje v končetinách po obou stranách těla, s podobnou základní frekvencí kmitání. To naznačuje, že kontralaterální třesy mohou mít společný zdroj nebo jsou jinak spojené. Ve své studii jsem prozkoumala vazbu mezi třesem levé a pravé ruky. Pomocí 3D- akcelerometrů jsem změřila časový průběh třesu, a použila stacionární i nestacionární (waveletové) výpočetní metody k vyhodnocení bilaterální koherence. Měření na všech třech prostorových osách umožnilo prozkoumat ucelenější sadu kinematických proměnných, než ve většině předešlých studií. Nestacionární analýza usnadnila identifikaci časově transientní koherence, což je scénář, který se v analýze třesu dříve nebral v úvahu. U většiny subjektů s PT...Rhythmic motions, regular or irregular, are an integral part of motor behavior both in health and in disease. Better understanding of its neural control mechanisms helps in developing methods for controlling the progression of diseases manifesting as rhythmic motions. I studied two specific aspects of rhythmic motions: bilateral coordination of hand tremors in human subjects and modular control of locomotion in invertebrates. Many types of tremors, including the physiological tremor (PT) and the essential tremor (ET) occur in limbs on both the sides of the body, with similar fundamental frequency of the oscillation. This raises the possibility that the contralateral tremors may have a common source or are otherwise coupled. However, while significant contralateral interaction is seen in these two types of tremors, only limited evidence of bilateral coherence has been shown in the previous literature. Therefore, in my study I explored the existence of a weak coupling between the left and right oscillators the may lead to intermittent bilateral coherence. I measured triaxial acceleration of the two hands and systematically assessed their bilateral coherence, using both stationary and non-stationary (wavelet-based) analyses methods. Measuring all three axes allowed examination of a more complete set...Institute of Biophysics and Informatics First Faculty of Medicine Charles University in PragueÚstav biofyziky a informatiky 1. LF UK v PrazeFirst Faculty of Medicine1. lékařská fakult

Low-Cost Sensors and Biological Signals

Many sensors are currently available at prices lower than USD 100 and cover a wide range of biological signals: motion, muscle activity, heart rate, etc. Such low-cost sensors have metrological features allowing them to be used in everyday life and clinical applications, where gold-standard material is both too expensive and time-consuming to be used. The selected papers present current applications of low-cost sensors in domains such as physiotherapy, rehabilitation, and affective technologies. The results cover various aspects of low-cost sensor technology from hardware design to software optimization