Celia Clarke - Academia.edu (original) (raw)

Papers by Celia Clarke

Journal of Neuroscience Methods, 2009

A novel method of optimal spectral tracking is presented which permits the characterisation of tr... more A novel method of optimal spectral tracking is presented which permits the characterisation of trial-varying parameters. Many experimental studies suffer from the limitations of available analysis methodologies, which often impose a condition of stationarity. This severely limits our ability to track slow varying or dynamic responses with any statistical certainty. Presented is a complete framework for the non-stationary analysis of trial-varying data. Theory is introduced and developed in the characterisation of speed dependent neural modulation of the locomotor drive to tibialis anterior (TA) during healthy treadmill locomotion. The approach adopts adaptive filter theory while retaining a spectral focus, thus remaining compatible with much of the current literature. Spectral tracking procedures are evaluated using both surrogate and neurophysiological time-series. Confidence intervals are derived in both empiric and numerical form. Analysis of the pre-synaptic drive to TA under the modulation of treadmill belt speed follows, with results demonstrating clear speed dependent influences on the spectral content of TA, suggesting dynamic neural modulation of the locomotor drive. Findings include speed-modulated components at 7-12 Hz (early swing) and 15-20 Hz (pre-stance). Speed invariant components were identified at 8-15 and 15-20 Hz during early and late swing, in agreement with previous studies. Modification to the method permits a sub-optimal alternative, encouraging the exploration of short epoched data.

Annals of the Rheumatic Diseases, 2016

Background: Muscular weakness is a cause of instability that has been reported to contribute to f... more Background: Muscular weakness is a cause of instability that has been reported to contribute to falling. Isokinetic and isometric dynamometry is a method of muscle assessment useful to measure the muscular strength and gives a quantification of the weakness and a comparison of strength across limbs and in reciprocal muscles. Objectives: To compare isokinetic and isometric knee flexion and extension strength between fallers and non-fallers with Rheumatoid Arthritis (RA). Methods: Sixty people with RA who gave informed consent were divided into two groups based on having a fall or not in the period of one year before evaluation, fallers (n=30, age 72.4years 15 males) and non-fallers (n=30, age 72.5 years, 16 males). Knee flexor and extensor strength was assessed using isokinetic and isometric dynamometry. Participants both limbs were tested at three fixed angular velocities isokinetically: 120°/s, 90°/s, and 60°/s and at three fixed positions isometrically, 90°, 60°and 30°. Bilateral comparison was determined by the percent deficit between left and right limbs for each participant. The ipsilateral comparison was determined between reciprocal muscles by the flexion/extension ratio. Independent t-test was used to identify significant differences between the fallers and non-fallers. The significance level was set at p<0.05 Results: 25 fallers and 30 non-fallers completed the isometric tests and 23 fallers and 28 non-fallers completed the isokinetic tests. In the bilateral comparison of the weaker and stronger limb in the fallers and non-fallers groups showed a large percentage deficit (range 22-43%) of isokinetic muscle strength between limbs in flexion and extension. Fallers had a significantly larger percentage deficit than non-fallers of isometric muscle strength between limbs in extension at 90°(p=0.02) and 60°(p=0.01). The ipsilateral comparison shows that the fallers had a significantly (p<0.05) smaller flexion/extension ratio indicating a reduced hamstring strength at all isokinetic speeds (120°/sec F:0.73, NF:0.97, 90°/sec F:0.75, NF:0.94, 60°/sec F:0.74, NF:0.90). The fallers also had a significantly (p<0.05) smaller flexion/extension ratio isometrically at 60°and 30°. Conclusions: These results demonstrate both RA fallers and RA non-fallers showed a large deficit in muscle strength between limbs. RA fallers had a significantly larger limb deficit in isometric extensor strength at 90°and 60°. The RA fallers had a significantly reduced flexion/extension ratio compared to the RA non-fallers indicating an imbalance between quadriceps and hamstring strength. Addressing the weakness in one limb and the imbalance between quadriceps and hamstrings may reduce the number of falls in this population.

Medical Engineering & Physics, 2011

BACKGROUND: The ability to objectively analyze gait in a clinical environment is challenging due ... more BACKGROUND: The ability to objectively analyze gait in a clinical environment is challenging due to time, space and cost constraints. This study investigated the validity of a portable gait assessment tool in objectively assessing the temporal gait parameters in subjects with spinal cord injury. The portable gait assessment tool consisted of a pair of insoles instrumented with force sensing resistors that were strategically positioned over the sole of each foot. AIM: To demonstrate the validity of the gait assessment tool by assessing the change in walking ability in incomplete spinal cord injured (ISCI) subjects, who participated in a robot-assisted gait training program. METHODS: Eighteen subjects with either an acute or chronic ISCI participated in this study (age range 26-63 years). Each subject participated in a robot assisted gait training programme for 6 weeks. Assessments were performed using the gait assessment tool before during and after the intervention. RESULTS: The gait assessment tool showed greater sensitivity to the change in the subject's gait, when compared to clinical assessments such as the walking index in spinal cord injury (WISCI II). Subjects with an acute ISCI showed a statistically significant (p<0.05) change in temporal gait parameters within the first 3 weeks of training. DISCUSSION AND CONCLUSION: This study for the first time has used the gait assessment tool in an ISCI population and has demonstrated that gait parameters can be measured and changes can be quantified within a clinical environment. The statistically significant changes during the first 3 weeks of training may indicate that an effective dose of robotic training can be administered within a relatively short period in ISCI subjects during the acute phase.

Additional file 1. Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 20... more Additional file 1. Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 Checklist.

Rheumatology, 2021

Objective To identify the clinical and biomechanical characteristics associated with falls in peo... more Objective To identify the clinical and biomechanical characteristics associated with falls in people with RA. Methods A total of 436 people ≥60 years of age with RA completed a 1 year prospective survey of falls in the UK. At baseline, questionnaires recorded data including personal and medical history, pain and fatigue scores, health-related quality of life (HRQoL), physical activity and medication history. The occurrence of falls wasmonitored prospectively over 12 months by monthly self-reporting. A nested sample of 30 fallers (defined as the report of one or more falls in 12 months) and 30 non-fallers was evaluated to assess joint range of motion (ROM), muscle strength and gait parameters. Multivariate regression analyses were undertaken to determine variables associated with falling. Results Compared with non-fallers (n = 236), fallers (n = 200) were older (P = 0.05), less likely to be married (P = 0.03), had higher pain scores (P < 0.01), experienced more frequent dizziness ...

Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next... more Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next two decades leading to an associated increase in total knee replacement (TKR) surgery. Although there is little debate regarding the safety and efficacy of modern TKR, up to 20% (Baker et al 2007) of patients report poor functional outcomes following surgery. This study will look at the functional outcome of two TKR; the JOURNEY II Bi Cruciate Stabilised knee, a newer prosthesis designed to provide guided motion and improve knee kinematics by more closely approximating a normal knee and the GENESIS II, a proven existing design. Aim: The aim of the CAPAbility study is to compare the change in patient reported outcome scores, of the JOURNEY II BCS and the GENESIS II from pre-operation to six months post-operation. Methods: CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral knee replacemen...

International Journal of Sports Medicine

The objectives of this randomized, cross-over pilot study were to determine whether isometric pla... more The objectives of this randomized, cross-over pilot study were to determine whether isometric plantarflexion exercises resulted in an immediate change in Achilles tendon pain during a loading task, and whether this differed in knee extension or flexion. Eleven participants with mid-portion Achilles tendinopathy were recruited from NHS community physiotherapy services and local running clubs. Participants were then randomized to complete an isometric calf muscle exercise with the knee fully extended or flexed to 80°. Participants switched to the alternate exercise after a minimum seven-day period. Achilles tendon pain during a specific, functional load test was measured on a 11-point numeric pain rating scale (NPRS) pre- and post-intervention. There was a small, immediate, mean reduction in pain following isometric plantar flexion performed in both knee extension (1.6, 95%CI 0.83 to 2.45, p=0.001) and knee flexion (1.3, 95%CI 0.31 to 2.19, p=0.015). There were no significant differen...

Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next... more Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next two decades leading to an associated increase in total knee replacement (TKR) surgery. Although there is little debate regarding the safety and efficacy of modern TKR, up to 20% of patients report poor functional outcomes following surgery. This study will investigate the functional outcome of two TKR; the JOURNEY II Bi Cruciate Stabilised knee, a newer prosthesis designed to provide guided motion and improve knee kinematics by more closely approximating a normal knee and the GENESIS II, a proven existing design. Aim: To compare the change in patient reported outcome scores of the JOURNEY II BCS and the GENESIS II from pre-operation to six months post-operation. Methods : CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral TKR surgery across two UK hospitals. Eligible participants (n=80)...

NeuroRehabilitation, 2014

Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects ... more Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects with incomplete spinal cord injury (ISCI) has not been quantified using objective outcome measures. To record changes in the force generating capacity of lower limb muscles (recorded as peak voluntary isometric torque at the knee and hip), before, during and after RAGT in both acute and subacute/chronic ISCI subjects using a repeated measures study design. Eighteen subjects with ISCI participated in this study (Age range: 26-63 years mean age = 49.3 ± 11 years). Each subject participated in the study for a total period of eight weeks, including 6 weeks of RAGT using the Lokomat system (Hocoma AG, Switzerland). Peak torques were recorded in hip flexors, extensors, knee flexors and extensors using torque sensors that are incorporated within the Lokomat. All the tested lower limb muscle groups showed statistically significant (p < 0.001) increases in peak torques in the acute subjects. C...

Archives of Physical Medicine and Rehabilitation, 2010

initial inpatient rehabilitation and postdischarge up to the first anniversary of injury. Inpatie... more initial inpatient rehabilitation and postdischarge up to the first anniversary of injury. Inpatient data were collected prospectively by clinicians providing treatment; postdischarge service data were collected retrospectively by patient self-report during follow-up interviews. Results: Of the total hours spent on these rehabilitation interventions during the first year after injury, 46% occurred after discharge from inpatient rehabilitation. Participants received 57% of their PT hours after discharge and 53% of their OT hours, but only a minority received any postdischarge services from other rehabilitation disciplines. While wide variation was found in the total hours of inpatient treatment across all disciplines, the variation in the total hours of postdischarge services was even greater, with the interquartile range of postdischarge services being twice that of the inpatient services. Conclusions: SCI rehabilitation, at least for many individuals, is given in a continuum with inpatient rehabilitation being only the beginning. Reductions in inpatient SCI rehabilitation length of stay are well-documented, but the postdischarge services that replace inpatient treatment appear to be more significant than previously reported. This points to the importance of studying the availability and impact of postdischarge care in greater detail to explain SCI rehabilitation outcomes, and a need for the development of better methods to capture the wide array of postdischarge services.

Journal of Neuroscience Methods, 2009

A novel method of optimal spectral tracking is presented which permits the characterisation of tr... more A novel method of optimal spectral tracking is presented which permits the characterisation of trial-varying parameters. Many experimental studies suffer from the limitations of available analysis methodologies, which often impose a condition of stationarity. This severely limits our ability to track slow varying or dynamic responses with any statistical certainty. Presented is a complete framework for the non-stationary analysis of trial-varying data. Theory is introduced and developed in the characterisation of speed dependent neural modulation of the locomotor drive to tibialis anterior (TA) during healthy treadmill locomotion. The approach adopts adaptive filter theory while retaining a spectral focus, thus remaining compatible with much of the current literature. Spectral tracking procedures are evaluated using both surrogate and neurophysiological time-series. Confidence intervals are derived in both empiric and numerical form. Analysis of the pre-synaptic drive to TA under the modulation of treadmill belt speed follows, with results demonstrating clear speed dependent influences on the spectral content of TA, suggesting dynamic neural modulation of the locomotor drive. Findings include speed-modulated components at 7-12 Hz (early swing) and 15-20 Hz (pre-stance). Speed invariant components were identified at 8-15 and 15-20 Hz during early and late swing, in agreement with previous studies. Modification to the method permits a sub-optimal alternative, encouraging the exploration of short epoched data.

Annals of the Rheumatic Diseases, 2016

Background: Muscular weakness is a cause of instability that has been reported to contribute to f... more Background: Muscular weakness is a cause of instability that has been reported to contribute to falling. Isokinetic and isometric dynamometry is a method of muscle assessment useful to measure the muscular strength and gives a quantification of the weakness and a comparison of strength across limbs and in reciprocal muscles. Objectives: To compare isokinetic and isometric knee flexion and extension strength between fallers and non-fallers with Rheumatoid Arthritis (RA). Methods: Sixty people with RA who gave informed consent were divided into two groups based on having a fall or not in the period of one year before evaluation, fallers (n=30, age 72.4years 15 males) and non-fallers (n=30, age 72.5 years, 16 males). Knee flexor and extensor strength was assessed using isokinetic and isometric dynamometry. Participants both limbs were tested at three fixed angular velocities isokinetically: 120°/s, 90°/s, and 60°/s and at three fixed positions isometrically, 90°, 60°and 30°. Bilateral comparison was determined by the percent deficit between left and right limbs for each participant. The ipsilateral comparison was determined between reciprocal muscles by the flexion/extension ratio. Independent t-test was used to identify significant differences between the fallers and non-fallers. The significance level was set at p<0.05 Results: 25 fallers and 30 non-fallers completed the isometric tests and 23 fallers and 28 non-fallers completed the isokinetic tests. In the bilateral comparison of the weaker and stronger limb in the fallers and non-fallers groups showed a large percentage deficit (range 22-43%) of isokinetic muscle strength between limbs in flexion and extension. Fallers had a significantly larger percentage deficit than non-fallers of isometric muscle strength between limbs in extension at 90°(p=0.02) and 60°(p=0.01). The ipsilateral comparison shows that the fallers had a significantly (p<0.05) smaller flexion/extension ratio indicating a reduced hamstring strength at all isokinetic speeds (120°/sec F:0.73, NF:0.97, 90°/sec F:0.75, NF:0.94, 60°/sec F:0.74, NF:0.90). The fallers also had a significantly (p<0.05) smaller flexion/extension ratio isometrically at 60°and 30°. Conclusions: These results demonstrate both RA fallers and RA non-fallers showed a large deficit in muscle strength between limbs. RA fallers had a significantly larger limb deficit in isometric extensor strength at 90°and 60°. The RA fallers had a significantly reduced flexion/extension ratio compared to the RA non-fallers indicating an imbalance between quadriceps and hamstring strength. Addressing the weakness in one limb and the imbalance between quadriceps and hamstrings may reduce the number of falls in this population.

Medical Engineering & Physics, 2011

BACKGROUND: The ability to objectively analyze gait in a clinical environment is challenging due ... more BACKGROUND: The ability to objectively analyze gait in a clinical environment is challenging due to time, space and cost constraints. This study investigated the validity of a portable gait assessment tool in objectively assessing the temporal gait parameters in subjects with spinal cord injury. The portable gait assessment tool consisted of a pair of insoles instrumented with force sensing resistors that were strategically positioned over the sole of each foot. AIM: To demonstrate the validity of the gait assessment tool by assessing the change in walking ability in incomplete spinal cord injured (ISCI) subjects, who participated in a robot-assisted gait training program. METHODS: Eighteen subjects with either an acute or chronic ISCI participated in this study (age range 26-63 years). Each subject participated in a robot assisted gait training programme for 6 weeks. Assessments were performed using the gait assessment tool before during and after the intervention. RESULTS: The gait assessment tool showed greater sensitivity to the change in the subject's gait, when compared to clinical assessments such as the walking index in spinal cord injury (WISCI II). Subjects with an acute ISCI showed a statistically significant (p<0.05) change in temporal gait parameters within the first 3 weeks of training. DISCUSSION AND CONCLUSION: This study for the first time has used the gait assessment tool in an ISCI population and has demonstrated that gait parameters can be measured and changes can be quantified within a clinical environment. The statistically significant changes during the first 3 weeks of training may indicate that an effective dose of robotic training can be administered within a relatively short period in ISCI subjects during the acute phase.

Additional file 1. Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 20... more Additional file 1. Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 Checklist.

Rheumatology, 2021

Objective To identify the clinical and biomechanical characteristics associated with falls in peo... more Objective To identify the clinical and biomechanical characteristics associated with falls in people with RA. Methods A total of 436 people ≥60 years of age with RA completed a 1 year prospective survey of falls in the UK. At baseline, questionnaires recorded data including personal and medical history, pain and fatigue scores, health-related quality of life (HRQoL), physical activity and medication history. The occurrence of falls wasmonitored prospectively over 12 months by monthly self-reporting. A nested sample of 30 fallers (defined as the report of one or more falls in 12 months) and 30 non-fallers was evaluated to assess joint range of motion (ROM), muscle strength and gait parameters. Multivariate regression analyses were undertaken to determine variables associated with falling. Results Compared with non-fallers (n = 236), fallers (n = 200) were older (P = 0.05), less likely to be married (P = 0.03), had higher pain scores (P < 0.01), experienced more frequent dizziness ...

Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next... more Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next two decades leading to an associated increase in total knee replacement (TKR) surgery. Although there is little debate regarding the safety and efficacy of modern TKR, up to 20% (Baker et al 2007) of patients report poor functional outcomes following surgery. This study will look at the functional outcome of two TKR; the JOURNEY II Bi Cruciate Stabilised knee, a newer prosthesis designed to provide guided motion and improve knee kinematics by more closely approximating a normal knee and the GENESIS II, a proven existing design. Aim: The aim of the CAPAbility study is to compare the change in patient reported outcome scores, of the JOURNEY II BCS and the GENESIS II from pre-operation to six months post-operation. Methods: CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral knee replacemen...

International Journal of Sports Medicine

The objectives of this randomized, cross-over pilot study were to determine whether isometric pla... more The objectives of this randomized, cross-over pilot study were to determine whether isometric plantarflexion exercises resulted in an immediate change in Achilles tendon pain during a loading task, and whether this differed in knee extension or flexion. Eleven participants with mid-portion Achilles tendinopathy were recruited from NHS community physiotherapy services and local running clubs. Participants were then randomized to complete an isometric calf muscle exercise with the knee fully extended or flexed to 80°. Participants switched to the alternate exercise after a minimum seven-day period. Achilles tendon pain during a specific, functional load test was measured on a 11-point numeric pain rating scale (NPRS) pre- and post-intervention. There was a small, immediate, mean reduction in pain following isometric plantar flexion performed in both knee extension (1.6, 95%CI 0.83 to 2.45, p=0.001) and knee flexion (1.3, 95%CI 0.31 to 2.19, p=0.015). There were no significant differen...

Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next... more Background: Osteoarthritis of the knee is a common condition that is expected to rise in the next two decades leading to an associated increase in total knee replacement (TKR) surgery. Although there is little debate regarding the safety and efficacy of modern TKR, up to 20% of patients report poor functional outcomes following surgery. This study will investigate the functional outcome of two TKR; the JOURNEY II Bi Cruciate Stabilised knee, a newer prosthesis designed to provide guided motion and improve knee kinematics by more closely approximating a normal knee and the GENESIS II, a proven existing design. Aim: To compare the change in patient reported outcome scores of the JOURNEY II BCS and the GENESIS II from pre-operation to six months post-operation. Methods : CAPAbility is a pragmatic, blinded, two-arm parallel, randomised controlled trial recruiting patients with primary osteoarthritis due to have unilateral TKR surgery across two UK hospitals. Eligible participants (n=80)...

NeuroRehabilitation, 2014

Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects ... more Strength changes in lower limb muscles following robot assisted gait training (RAGT) in subjects with incomplete spinal cord injury (ISCI) has not been quantified using objective outcome measures. To record changes in the force generating capacity of lower limb muscles (recorded as peak voluntary isometric torque at the knee and hip), before, during and after RAGT in both acute and subacute/chronic ISCI subjects using a repeated measures study design. Eighteen subjects with ISCI participated in this study (Age range: 26-63 years mean age = 49.3 ± 11 years). Each subject participated in the study for a total period of eight weeks, including 6 weeks of RAGT using the Lokomat system (Hocoma AG, Switzerland). Peak torques were recorded in hip flexors, extensors, knee flexors and extensors using torque sensors that are incorporated within the Lokomat. All the tested lower limb muscle groups showed statistically significant (p < 0.001) increases in peak torques in the acute subjects. C...

Archives of Physical Medicine and Rehabilitation, 2010

initial inpatient rehabilitation and postdischarge up to the first anniversary of injury. Inpatie... more initial inpatient rehabilitation and postdischarge up to the first anniversary of injury. Inpatient data were collected prospectively by clinicians providing treatment; postdischarge service data were collected retrospectively by patient self-report during follow-up interviews. Results: Of the total hours spent on these rehabilitation interventions during the first year after injury, 46% occurred after discharge from inpatient rehabilitation. Participants received 57% of their PT hours after discharge and 53% of their OT hours, but only a minority received any postdischarge services from other rehabilitation disciplines. While wide variation was found in the total hours of inpatient treatment across all disciplines, the variation in the total hours of postdischarge services was even greater, with the interquartile range of postdischarge services being twice that of the inpatient services. Conclusions: SCI rehabilitation, at least for many individuals, is given in a continuum with inpatient rehabilitation being only the beginning. Reductions in inpatient SCI rehabilitation length of stay are well-documented, but the postdischarge services that replace inpatient treatment appear to be more significant than previously reported. This points to the importance of studying the availability and impact of postdischarge care in greater detail to explain SCI rehabilitation outcomes, and a need for the development of better methods to capture the wide array of postdischarge services.