<p>Neuroimaging and neurophysiology techniques were used to study some aspects of cortical sensory and motor system reorganisation in patients in the chronic phase after stroke. Using Diffusion Tensor Imaging, we found that the degree of white matter integrity of the corticofugal tracts (CFT) was positively related to grip strength. Structural changes of the CFT were also associated with functional changes in the corticospinal pathways, measured using Transcranial Magnetic Stimulation. This suggests that structural and functional integrity of the CFT is essential for upper limb function after stroke.</p><p>Using functional magnetic resonance imaging (fMRI), to measure brain activity during slow and fast passive hand movements, we found that velocity-dependent brain activity correlated positively with neural contribution to passive movement resistance in the hand in ipsilateral primary sensory (S1) and motor (M1) cortex in both patients and controls. This suggests a cortical involvement in the hyperactive reflex response of flexor muscles upon fast passive stretch.</p><p>Effects of a four week passive-active movement training programme were evaluated in chronic stroke patients. The group improved in range of motion and upper limb function after the training. The patients also reported improvements in a variety of daily tasks requiring the use of the affected upper limb. </p><p>Finally, we used fMRI to explore if brain activity during passive hand movement is related to time after stroke, and if such activity can be affected with intense training. In patients, reduced activity over time was found in supplementary motor area (SMA), contralateral M1 and prefrontal and parietal association areas along with ipsilateral cerebellum. After training, brain activity increased in SMA, ipsilateral S1 and intraparietal sulcus, and contralateral cerebellum in parallel with functional improvements of the upper limb. The findings suggest a use-dependent modification of cortical activation patterns in the affected hand after stroke. </p>

Neuroimaging and neurophysiology techniques were used to study some aspects of cortical sensory and motor system reorganisation in patients in the chronic phase after stroke. Using Diffusion Tensor Imaging, we found that the degree of white matter integrity of the corticofugal tracts (CFT) was positively related to grip strength. Structural changes of the CFT were also associated with functional changes in the corticospinal pathways, measured using Transcranial Magnetic Stimulation. This suggests that structural and functional integrity of the CFT is essential for upper limb function after stroke. Using functional magnetic resonance imaging (fMRI), to measure brain activity during slow and fast passive hand movements, we found that velocity-dependent brain activity correlated positively with neural contribution to passive movement resistance in the hand in ipsilateral primary sensory (S1) and motor (M1) cortex in both patients and controls. This suggests a cortical involvement in the hyperactive reflex response of flexor muscles upon fast passive stretch. Effects of a four week passive-active movement training programme were evaluated in chronic stroke patients. The group improved in range of motion and upper limb function after the training. The patients also reported improvements in a variety of daily tasks requiring the use of the affected upper limb. Finally, we used fMRI to explore if brain activity during passive hand movement is related to time after stroke, and if such activity can be affected with intense training. In patients, reduced activity over time was found in supplementary motor area (SMA), contralateral M1 and prefrontal and parietal association areas along with ipsilateral cerebellum. After training, brain activity increased in SMA, ipsilateral S1 and intraparietal sulcus, and contralateral cerebellum in parallel with functional improvements of the upper limb. The findings suggest a use-dependent modification of cortical activation patterns in the affected hand after stroke.

Study Design: A blinded, prospective diagnostic test study was conducted.<p>Objectives: To assess the inter-tester reliability of clinical examination items for carpal tunnel syndrome (CTS), to assess the validity of individual clinical test items and self-report measures for the diagnosis of CTS and to assess the accuracy of an optimum test item cluster for the diagnosis of CTS.<p>Study Rational: Examination of the diagnostic validity of various clinical tests for the diagnosis of CTS has shown mixed results and the reliability of many of these tests has not been determined. The majority of the diagnostic validity research for CTS has examined tests individually which is in contrast to clinical practice where the results of multiple tests are combined as part of the clinical reasoning process in order to formulate a differential diagnosis: the test item cluster, derived through logistic regression, is proposed as a means to integrate the validity of multiple tests. Methods: 37 subjects (74 hands) were recruited from a convenience sample of consecutive patients referred to for electrodiagnostic (EDX) testing due to upper extremity symptomatic complaints. Subjects underwent EDX testing followed by completion of self-report questionnaires and a standardized clinical examination by examiners blinded to EDX results. Diagnostic validity was determined for both general and restricted CTS classification groupings. <p>Results: Out of 18 clinical test items, 12 had reliability coefficients (i.e. ICC or Kappa) of .40 or greater. There were 10 clinical exam and self-report items that were found to have likelihood point estimates above 2 or below 0.50 for the general diagnostic classification and 6 items had acceptable validity for the restricted classification. The test item cluster (TIC) derived for the general classification included hand numbness and symptom reproduction with the upper limb neurodynamic test 1. The TIC derived for the restricted classification included hand numbness and the overall score of the symptom component of the Bringham Carpal Tunnel Questionnaire. The 95% confidence intervals for most likelihood ratio point estimates were wide. <p>Conclusions: The TICs for both classification groupings did not yield improved diagnostic validity beyond that found with the single best test item (hand numbness). The value of the single best test item hand numbness was in a negative response. Further investigation is required to validate the TIC and the single best test item and to improve the point estimate precision.

Head position signal is crucial for preparing reaching movements because it contributes to specifying the position of body and target in space and relative to each other. However, it is unclear whether sensory information pertaining head position is used to control the movement after movement onset. In this study, nineteen participants performed discrete reaches towards a virtual target while neck vibration was randomly applied before and/or during the movement or not at all. The main dependent variable was the directional bias of the reaching finger. Neck vibration induced early leftward or late rightward trajectory biases. It appears that participants interpreted the sensed head shift as a target or an eye-in-head motion, which can be explained by individual differences in the use of reference frames. Nevertheless, body-centered and head-centered frames of reference appear to be important for the early and late stages of a goal-directed movement, respectively.

Head position signal is crucial for preparing reaching movements because it contributes to specifying the position of body and target in space and relative to each other. However, it is unclear whether sensory information pertaining head position is used to control the movement after movement onset. In this study, nineteen participants performed discrete reaches towards a virtual target while neck vibration was randomly applied before and/or during the movement or not at all. The main dependent variable was the directional bias of the reaching finger. Neck vibration induced early leftward or late rightward trajectory biases. It appears that participants interpreted the sensed head shift as a target or an eye-in-head motion, which can be explained by individual differences in the use of reference frames. Nevertheless, body-centered and head-centered frames of reference appear to be important for the early and late stages of a goal-directed movement, respectively.

Study Design: A blinded, prospective diagnostic test study was conducted.<p>Objectives: To assess the inter-tester reliability of clinical examination items for carpal tunnel syndrome (CTS), to assess the validity of individual clinical test items and self-report measures for the diagnosis of CTS and to assess the accuracy of an optimum test item cluster for the diagnosis of CTS.<p>Study Rational: Examination of the diagnostic validity of various clinical tests for the diagnosis of CTS has shown mixed results and the reliability of many of these tests has not been determined. The majority of the diagnostic validity research for CTS has examined tests individually which is in contrast to clinical practice where the results of multiple tests are combined as part of the clinical reasoning process in order to formulate a differential diagnosis: the test item cluster, derived through logistic regression, is proposed as a means to integrate the validity of multiple tests. Methods: 37 subjects (74 hands) were recruited from a convenience sample of consecutive patients referred to for electrodiagnostic (EDX) testing due to upper extremity symptomatic complaints. Subjects underwent EDX testing followed by completion of self-report questionnaires and a standardized clinical examination by examiners blinded to EDX results. Diagnostic validity was determined for both general and restricted CTS classification groupings. <p>Results: Out of 18 clinical test items, 12 had reliability coefficients (i.e. ICC or Kappa) of .40 or greater. There were 10 clinical exam and self-report items that were found to have likelihood point estimates above 2 or below 0.50 for the general diagnostic classification and 6 items had acceptable validity for the restricted classification. The test item cluster (TIC) derived for the general classification included hand numbness and symptom reproduction with the upper limb neurodynamic test 1. The TIC derived for the restricted classification included hand numbness and the overall score of the symptom component of the Bringham Carpal Tunnel Questionnaire. The 95% confidence intervals for most likelihood ratio point estimates were wide. <p>Conclusions: The TICs for both classification groupings did not yield improved diagnostic validity beyond that found with the single best test item (hand numbness). The value of the single best test item hand numbness was in a negative response. Further investigation is required to validate the TIC and the single best test item and to improve the point estimate precision.

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Upper limb deficits post stroke affect up to 60% of stroke survivors. The assessment of motor deficits post stroke is important for identifying rehabilitation goals and assessing treatment efficacy. Current clinical tools used to assess motor impairment utilize clinical observation to describe the performance of diagnostic motor tasks. However there are some concerns regarding the ability of these scales to fully describe the quality of performance, and detect small but important changes which reflect motor recovery. Kinematic analysis has been increasingly suggested to augment clinical assessment; however, current kinematic tools are not well suited to the time and financial constraints of a clinical environment. The objective of this thesis was to investigate the feasibility of utilizing low-cost, depth sensing technology (Kinect sensor) to augment the current upper limb stroke assessment. Study one characterizes the accuracy of the Kinect sensor, and defines optimal markers and conditions for data collection. Results revealed sufficient ability to quantify metrics for the hand, and the trunk. Study two explored the feasibility of clinical use for the Kinect sensor, specifically its ability to distinguish kinematic performance between the affected and less-affected limbs within an individual, and differences in the affected limb between individuals. Results from study 2 indicated that the Kinect is able to identify interlimb differences and correlations with upper limb impairment scores for some kinematic metrics. Findings from this thesis suggest a potential use for the Kinect in a clinical environment for the purposes of upper limb stroke assessment; however, there are many factors and limitations which need to be considered prior to its use.

Cross-correlation is often used as the primary technique to compare two biological signals. The cross-correlation technique is an effective means to measure the synchronization of two signals if the relative phases at all frequencies are distributed linearly, that is, there is a group delay. The group delay assumption of cross-correlation analysis imposes an unfavourable restriction on signals with relative phase correlation which varies at different frequencies. Traditional Fourier analysis applied to a short data segments, namely the Short Time Fourier Transform (STFT), provides phase information for each frequency component, but it is not suitable for biological signals with non-stationary statistics for which the ideal segment length is unknown. The application of a wavelet based phase analysis technique is discussed in this study. The frequency decomposition and temporally localized nature of the wavelet transform provides localized phase-frequency information for two signals. A wavelet frequency temporal relative phase pattern (WFT-RPP) technique to extract relative phase information at specific frequencies over the time course of a time-varying signal was developed. The technique was tested on simulated data and surface electromyographic (sEMG) data recorded from upper limb muscles in human subjects as they performed a series of dynamic push and pull tasks. Selected sEMG channel pairs are compared against each other using the WFT-RPP technique to extract the relative phase information and repetitive relative phase patterns for certain muscle pairs were observed. The properties of the WFT-RPP and the merits and weaknesses of using the technique for determining intermuscular sEMG synchronization is discussed. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2011-09-13 11:58:16.014