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Lala D, Houghton PE, Kras-Dupuis A, Wolfe DL. Developing a Model of Care for Healing Pressure Ulcers With Electrical Stimulation Therapy for Persons With Spinal Cord Injury. Top Spinal Cord Inj Rehabil 2018; 22:277-287. [PMID: 29339869 DOI: 10.1310/sci2204-277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Background: Electrical stimulation therapy (EST) has been shown to be an effective therapy for managing pressure ulcers in individuals with spinal cord injury (SCI). However, there is a lack of uptake of this therapy, and it is often not considered as a first-line treatment, particularly in the community. Objective: To develop a pressure ulcer model of care that is adapted to the local context by understanding the perceived barriers and facilitators to implementing EST, and to describe key initial phases of the implementation process. Method: Guided by the Knowledge-to-Action (KTA) and National Implementation Research Network (NIRN) frameworks, a community-based participatory research (CBPR) approach was used to complete key initial implementation processes including (a) defining the practice, (b) identifying the barriers and facilitators to EST implementation and organizing them into implementation drivers, and (c) developing a model of care that is adapted to the local environment. Results: A model of care for healing pressure ulcers with EST was developed for the local environment while taking into account key implementation barriers including lack of interdisciplinary collaboration and communication amongst providers between and across settings, inadequate training and education, and lack of resources, such as funding, time, and staff. Conclusions: Using established implementation science frameworks with structured planning and engaging local stakeholders are important exploratory steps to achieve a successful sustainable best practice implementation project.
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Affiliation(s)
- D Lala
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada
| | - P E Houghton
- Department of Health and Rehabilitation Sciences, Western University, London, Ontario, Canada.,School of Physical Therapy, Western University, London, Ontario
| | | | - D L Wolfe
- Parkwood Institute, London, Ontario, Canada
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Noonan VK, Wolfe DL, Thorogood NP, Park SE, Hsieh JT, Eng JJ. Knowledge translation and implementation in spinal cord injury: a systematic review. Spinal Cord 2014; 52:578-87. [PMID: 24796445 DOI: 10.1038/sc.2014.62] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/12/2014] [Accepted: 03/25/2014] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To conduct a systematic review examining the effectiveness of knowledge translation (KT) interventions in changing clinical practice and patient outcomes. METHODS MEDLINE/PubMed, CINAHL, EMBASE and PsycINFO were searched for studies published from January 1980 to July 2012 that reported and evaluated an implemented KT intervention in spinal cord injury (SCI) care. We reviewed and summarized results from studies that documented the implemented KT intervention, its impact on changing clinician behavior and patient outcomes as well as the facilitators and barriers encountered during the implementation. RESULTS A total of 13 articles featuring 10 studies were selected and abstracted from 4650 identified articles. KT interventions included developing and implementing patient care protocols, providing clinician education and incorporating outcome measures into clinical practice. The methods (or drivers) to facilitate the implementation included organizing training sessions for clinical staff, introducing computerized reminders and involving organizational leaders. The methodological quality of studies was mostly poor. Only 3 out of 10 studies evaluated the success of the implementation using statistical analyses, and all 3 reported significant behavior change. Out of the 10 studies, 6 evaluated the effect of the implementation on patient outcomes using statistical analyses, with 4 reporting significant improvements. The commonly cited facilitators and barriers were communication and resources, respectively. CONCLUSION The field of KT in SCI is in its infancy with only a few relevant publications. However, there is some evidence that KT interventions may change clinician behavior and improve patient outcomes. Future studies should ensure rigorous study methods are used to evaluate KT interventions.
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Affiliation(s)
- V K Noonan
- 1] Department of Orthopedics, University of British Columbia, Vancouver, British Columbia, Canada [2] Rick Hansen Institute, Vancouver, British Columbia, Canada
| | - D L Wolfe
- 1] Program of Aging, Rehabilitation and Geriatric Care, Lawson Health Research Institute, London, Ontario, Canada [2] Department of Physical Medicine and Rehabilitation, Western University, London, Ontario, Canada
| | - N P Thorogood
- Rick Hansen Institute, Vancouver, British Columbia, Canada
| | - S E Park
- 1] Department of Orthopedics, University of British Columbia, Vancouver, British Columbia, Canada [2] Rick Hansen Institute, Vancouver, British Columbia, Canada
| | - J T Hsieh
- Program of Aging, Rehabilitation and Geriatric Care, Lawson Health Research Institute, London, Ontario, Canada
| | - J J Eng
- 1] Department of Orthopedics, University of British Columbia, Vancouver, British Columbia, Canada [2] International Collaboration on Repair Discoveries, Vancouver, British Columbia, Canada
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Kawakita H, Kameyama O, Ogawa R, Hayes KC, Wolfe DL, Allatt RD. Reinforcement of motor evoked potentials by remote muscle contraction. J Electromyogr Kinesiol 2012; 1:96-106. [PMID: 20870499 DOI: 10.1016/1050-6411(91)90003-n] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/1991] [Indexed: 11/27/2022] Open
Abstract
We investigated the effects of remote muscle contraction on the amplitude and latency of motor-evoked potentials (MEPs) recorded from tibialis anterior and lateral gastrocnemius after transcranial magnetic stimulation of the motor cortex. In particular, consideration was given to the effects of unilateral handgrip of different strengths, jaw clench, and combined bilateral handgrip (Jendrassik maneuver) and jaw clench. Eight healthy adult volunteer subjects (six women, two men) participated in the main study. The clinical usefulness of this form of facilitation was subsequently demonstrated in three patients with myelopathy. Transcranial magnetic stimulation of the motor cortex was delivered from a Cadwell MES-10 (100% intensity) with a 9.5-cm circular coil positioned with the rim over the vertex. Stimuli were delivered ∼ 1 s after initiation of reinforcement. In the main study of normal subjects, surface recordings of the evoked compound muscle action potentials were made bilaterally from anterior tibialis and lateral gastrocnemius. In the individual studies of patients, MEPs were also recorded from abductor pollicis brevis and other muscles innervated from roots below the level of lesion. The principal results showed that unilateral handgrip (50 and 100% maximum voluntary contraction, MVC) of either hand enhanced the amplitude of MEPs bilaterally in both tibialis anterior and lateral gastrocnemius in all normal subiects (p < 0.05). The mean increase in amplitude associated with 100% MVC unilateral handgrip was >300% of the control value when the subject was relaxed (p < 0.01). The bilateral Jendrassik maneuver and jaw clench were also effective in increasing (p < 0.05) MEP amplitude in both muscle groups. These two procedures did not yield the same degree of reinforcement as 100% unilateral handgrip. Remote muscle contractions induced a reduction in MEP latency of 1-2 ms (p < 0.05). The clinical importance of these observations was demonstrated by the fact that remote muscle reinforcement enabled identification of low-amplitude MEPs that might otherwise have been missed in the three patients with spinal cord trauma.
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Affiliation(s)
- H Kawakita
- Department of Orthopaedic Surgery, Kansai Medical University, Osaka, Japan
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Abstract
STUDY DESIGN Comprehensive review and systematic analyses. OBJECTIVES Assess published psychometric evidence for spinal cord injury (SCI) spasticity outcome measures. Considerations about the influence of spasticity on function have also been identified to understand treatment effects and guide service delivery. SETTING London, Ontario and Vancouver, British Columbia, Canada. METHOD Review of measures was based on availability of psychometric data, application in clinical settings and evaluated in SCI patients. RESULTS Ashworth and Modified Ashworth Scales (AS, MAS), Penn Spasm Frequency Scale (PSFS), Spinal Cord Assessment Tool for Spasticity (SCATS), Visual Analogue Scale self-rated scale of spasticity (VAS) and the Wartenberg Pendulum Test (WPT) were included in this review. The most frequently used tools for SCI spasticity measurement include the AS, MAS, PSFS and VAS, of which the latter two are self-report spasticity measures. The SCATS has been partially validated for SCI, but is not widely used. The WPT has been minimally validated despite its use in a large-scale SCI spasticity randomized controlled trial. CONCLUSIONS Since spasticity is multidimensional, focusing on one or two spasticity outcome measures can misrepresent the extent and influence of spasticity on SCI patients. Different scales measure different aspects of spasticity and individual tools correlate weakly with each other. Spasticity may be better measured with an appropriate battery of tests, including the AS or MAS, along with PSFS. These tools would benefit from further reliability and responsiveness testing. Tools that assess the influence of spasticity on patient activities, participation and quality of life are important, but lacking.
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Affiliation(s)
- J T C Hsieh
- Lawson Health Research Institute, Aging Rehabilitation and Geriatric Care, London, Ontario, Canada.
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Martin Ginis KA, Latimer AE, Buchholz AC, Bray SR, Craven BC, Hayes KC, Hicks AL, McColl MA, Potter PJ, Smith K, Wolfe DL. Establishing evidence-based physical activity guidelines: methods for the Study of Health and Activity in People with Spinal Cord Injury (SHAPE SCI). Spinal Cord 2007; 46:216-21. [PMID: 17646838 DOI: 10.1038/sj.sc.3102103] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Prospective, observational cohort study. OBJECTIVES This paper describes the rationale and methodology for the Study of Health and Activity in People with Spinal Cord Injury (SHAPE SCI). The study aims to (1) describe physical activity levels of people with different injury levels and completeness, (2) examine the relationship between physical activity, risk and/or presence of secondary health complications and risk of chronic disease, and (3) identify determinants of physical activity in the SCI population. SETTING Ontario, Canada. METHODS Seven hundred and twenty men and women who have incurred a traumatic SCI complete self-report measures of physical activity, physical activity determinants, secondary health problems and subjective well-being during a telephone interview. A representative subsample (n=81) participate in chronic disease risk factor testing for obesity, insulin resistance and coronary heart disease. Measures are taken at baseline, 6 and 18 months. CONCLUSION SHAPE SCI will provide much-needed epidemiological information on physical activity patterns, determinants and health in people with SCI. This information will provide a foundation for the establishment of evidence-based physical activity guidelines and interventions tailored to the SCI community.
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Affiliation(s)
- K A Martin Ginis
- Department of Kinesiology, Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada.
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Hayes KC, Katz MA, Devane JG, Hsieh JTC, Wolfe DL, Potter PJ, Blight AR. Pharmacokinetics of an immediate-release oral formulation of Fampridine (4-aminopyridine) in normal subjects and patients with spinal cord injury. J Clin Pharmacol 2003; 43:379-85. [PMID: 12723458 DOI: 10.1177/0091270003251388] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Plasma concentration profiles of the K+ channel-blocking compound Fampridine were obtained from (1) control subjects (n = 6) following oral administration of doses of 10, 15, 20, and 25 mg and (2) patients with spinal cord injury (SCI) (n = 11) following a single oral dose of 10 mg of an immediate-release formulation. Plasma concentrations were determined using a reversed-phase ion-pair high-performance liquid chromatography (HPLC) assay with ultraviolet light detection employing liquid extraction. The drug was rapidly absorbed with a tmax approximately 1 hour for both groups; tmax was independent of dose. Cmax and AUC0-infinity were linearly related to dose, and t 1/2 was 3 to 4 hours for both groups. There were no obvious differences in the (10-mg) plasma concentration profiles between control subjects and SCI patients. The drug was well tolerated, with only mild and transient side effects of light-headedness, dysesthesias, and dizziness.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine and Rehabilitation, University of Western Ontario, Program of Rehabilitation and Geriatric Care, Lawson Health Research Institute, St. Joseph's Health Care London, London, Ontario, Canada
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Cotler SJ, Reddy KR, McCone J, Wolfe DL, Liu A, Craft TR, Ferris MW, Conrad AJ, Albrecht J, Morrissey M, Ganger DR, Rosenblate H, Blatt LM, Jensen DM, Taylor MW. An analysis of acute changes in interleukin-6 levels after treatment of hepatitis C with consensus interferon. J Interferon Cytokine Res 2001; 21:1011-9. [PMID: 11798458 DOI: 10.1089/107999001317205132] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cytokine production has been implicated in the antiviral response to interferon-alpha (IFN-alpha) in hepatitis C and in the development of IFN-alpha-related side effects. We characterized acute changes in serum cytokine levels following administration of a single dose of consensus IFN (IFN-con1) and during continuous treatment of chronic hepatitis C patients. Serum samples were collected at baseline, at multiple times early after IFN administration, and weekly thereafter. Viral RNA titers were assessed by RT-PCR, and viral kinetics were followed. ELISA assays were used to measure IFN-gamma, tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), IL-4, IL-6, and IL-16. Serum cytokine levels were low at baseline. IL-6 was detected in patients with hepatitis C but not in healthy control subjects by either ELISA or RT-PCR, indicating that low levels of circulating IL-6 were associated with hepatitis C infection. None of the cytokines measured increased significantly after IFN administration except for IL-6. IL-6 levels rose rapidly, peaked at 6-15 h in a dose-dependent manner, and returned to baseline by 48 h in both patients receiving a single dose of IFN and those receiving continuous treatment. This was confirmed by RT-PCR. Pretreatment IL-6 levels were directly correlated with area under the curve (AUC) for IL-6 during the 24 h after IFN dosing (r = 0.611, p = 0.007). Viral titers decreased within 24-48 h after a single dose of IFN-con1. Changes in hepatitis C RNA titers were not significantly associated with pretreatment IL-6 levels or with changes in IL-6 levels. In conclusion, (1) baseline serum cytokine levels, except for IL-6, were low or within the normal range in patients with hepatitis C, (2) IL-6 levels were detected in some patients with hepatitis C before treatment but not in healthy controls, (3) IL-6 levels increased acutely after a single dose of IFN-alpha, and IL-6 induction was related to baseline IL-6 level, and (4) changes in IL-6 levels did not correlate with the early virologic response to IFN.
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Affiliation(s)
- S J Cotler
- Section of Hepatology and Department of Preventive Medicine, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, USA
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Wolfe DL, Hayes KC, Hsieh JT, Potter PJ. Effects of 4-aminopyridine on motor evoked potentials in patients with spinal cord injury: a double-blinded, placebo-controlled crossover trial. J Neurotrauma 2001; 18:757-71. [PMID: 11526982 DOI: 10.1089/089771501316919120] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
4-Aminopyridine (4-AP) is a potassium (K+) channel blocking agent that has been shown to reduce the latency and increase the amplitude of motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation (TMS) in patients with chronic spinal cord injury (SCI). These effects on MEPs are thought to reflect enhanced conduction in long tract axons brought about by overcoming conduction deficits due to focal demyelination and/or by enhancing neuroneuronal transmission at one or more sites of the neuraxis. The present study was designed to obtain further evidence of reduced central motor conduction time (CMCT) and to determine whether MEPs could be recorded from paretic muscles in which they were not normally elicited. MEPs were elicited with TMS being delivered to subjects (n = 25) pre- and post-administration of 4-AP (10 mg capsule) or placebo. The principal finding was that 4-AP lowered the stimulation threshold, increased the amplitude and reduced the latency of MEPs in all muscles tested, including those that were unimpaired, but did not alter measures of the peripheral nervous system (i.e., M-wave, H-reflex, F-wave). These 4-AP-induced changes in MEPs were significantly greater than those seen with placebo (p < 0.05). The primary implication of these results is that a low dose of 4-AP (immediate-release formulation) appears to improve the impaired central motor conduction of some patients with incomplete SCI. This is most likely attributable to overcoming conduction deficits at the site of injury but may also involve an increase in cortical excitability.
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Affiliation(s)
- D L Wolfe
- Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, Canada.
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Wolfe DL, Stanton TJ. Legal liability under an IDM program. Empl Benefits J 2000; 25:9-16. [PMID: 11188408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
Integrated disability management (IDM) programs offer employers a simple, strategic approach to managing health and lost time. However, components of these programs also present potential liabilities under federal, and sometimes, state law. This article reviews the sources of these liabilities and summarizes techniques for minimizing the risk of employers (and managers individually).
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Affiliation(s)
- D L Wolfe
- Chicago Office, Gardner, Carton & Douglas, USA
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Hayes KC, Hsieh JT, Wolfe DL, Potter PJ, Delaney GA. Classifying incomplete spinal cord injury syndromes: algorithms based on the International Standards for Neurological and Functional Classification of Spinal Cord Injury Patients. Arch Phys Med Rehabil 2000; 81:644-52. [PMID: 10807106 DOI: 10.1016/s0003-9993(00)90049-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To develop an objective and uniform means for classifying patients with incomplete spinal cord injury (SCI) according to SCI syndromes. DESIGN Criteria for assigning the syndromes (defined by the International Standards for Neurological and Functional Classification of SCI Patients) were operationalized by means of sensory and motor scores and were incorporated into a set of six independent algorithms and two composite algorithms. SETTING A regional SCI rehabilitation center in Canada. PATIENTS SCI patients (n = 56) with incomplete injuries (American Spinal Injury Association classes B, C, D) and stable neurologic deficits. RESULTS Individual algorithms allowed the highest classification rate but with some patients meeting the criteria for more than one syndrome. A composite, differential allocation algorithm, with selected thresholds at decision nodes, yielded a classification rate approximating that of the individual algorithms but without double classifications. CONCLUSIONS The composite algorithm provided an objective and standardized means of assigning patients to syndromes based on clinically measurable sensory and motor scores. The thresholds used to implement criteria and the order of decision nodes greatly influenced the outcomes and may be adjusted to suit the needs of the classification, that is, embracing liberal or stringent criteria. Controversy remains about the interpretation of some syndromes, and many patients remain unclassifiable because of mixed clinical presentation.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine and Rehabilitation, Parkwood Hospital/St. Joseph's Health Centre, University of Western Ontario, London, Canada
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Abstract
OBJECTIVE To examine the utility of quantitative sensory testing (QST) to characterize sensory dysfunction in patients with spinal cord injury (SCI). DESIGN Perceptual thresholds to warm, cold, cold pain, and vibratory stimuli were investigated using a modified method of "limits." METHOD Three QST trials were administered to six lower leg dermatomes, on two different days, to estimate the reliability of measurement. SETTING Regional Spinal Cord Injury Rehabilitation Center in Ontario, Canada. SUBJECTS Twenty-one SCI patients with incomplete neurologic deficits and 14 able-bodied controls of similar age. RESULTS ANOVA revealed significantly (p < .05) reduced perceptual threshold values (hypoesthesia) for warm, cold, and vibratory sensation in the SCI group. There were no differences between group mean values for cold pain because of the inclusion of patients with hypoalgesia and hyperalgesia. Intraclass correlation coefficient estimates of reliability revealed large between-subject variability in the SCI patients associated with relatively small trial-to-trial variability within each day of testing, and appreciable between-day variances. CONCLUSIONS With QST in SCI there is a need for repeated measurements across days to establish stable baseline measures or outcomes following intervention. QST is a useful adjunct to clinical examination for assessment of preserved sensation.
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Affiliation(s)
- A Krassioukov
- Department of Physical Medicine & Rehabilitation, Parkwood Hospital/St. Joseph's Health Centre, The University of Western Ontario, London, Canada
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Wolfe DL, Hayes KC, Potter PJ, Delaney GA. Conditioning lower limb H-reflexes by transcranial magnetic stimulation of motor cortex reveals preserved innervation in SCI patients. J Neurotrauma 1996; 13:281-91. [PMID: 8835796 DOI: 10.1089/neu.1996.13.281] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Conditioning of lower limb H-reflexes by transcranial magnetic stimulation of motor cortex was used to detect preserved innervation in patients with long-standing spinal cord injury (SCI). Cortical stimulation was delivered at intensities suprathreshold or subthreshold for evoking motor evoked potentials (MEPs). The conditioning (C) cortical stimulation preceded the test (T) H-reflex stimulus at intervals between C-T: 10-300 msec. Conditioned H-reflex profiles in control subjects (n = 10), following both suprathreshold and subthreshold cortical conditioning, yielded evidence of early (C-T: 10-30 msec) and late arriving (C-T: 60-130 msec) excitatory inputs to the lateral gastrocnemius (LG) motoneuron pool. Demonstration of late inputs following subthreshold cortical conditioning suggested the inputs are mediated by slow conducting or oligosynaptic descending motor tracts, as distinct from afferent consequences of short latency MEPs. In SCI patients (n = 11) the conditioned H-reflex profile varied according to the patients' ASIA impairment rating. Higher functioning SCI patients (ASIA level C and D) revealed evidence of both early and late arriving inputs to the lumbosacral motoneuron pool whereas patients with more severe impairments (ASIA levels A and B) most often failed to exhibit early or late periods of H-reflex facilitation in LG. In three patients (i.e., 1 ASIA B; 2 ASIA C) the cortical modulation of H-reflex amplitudes yielded evidence of preserved corticospinal innervation that was not detectable by other MEP reinforcement procedures. These results introduce the cortical conditioning procedure as a sensitive means of detecting latent corticospinal and/or bulbospinal innervation in SCI patients consistent with the emerging neuropathological picture of preserved axonal integrity in descending motor tracts in the face of extensive functional loss.
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Affiliation(s)
- D L Wolfe
- Program in Neuroscience, University of Western Ontario, London, Canada
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Wolfe DL, Hayes KC. Conditioning effects of sural nerve stimulation on short and long latency motor evoked potentials in lower limb muscles. Electroencephalogr Clin Neurophysiol 1995; 97:11-7. [PMID: 7533716 DOI: 10.1016/0924-980x(94)00239-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The effects of conditioning sural nerve stimulation on motor evoked potentials (MEPs) in relaxed muscles of the lower limb were examined in 11 healthy adults. The study tested the hypothesis that cutaneous afferent stimulation, in the absence of muscle afferent input, facilitates the short latency MEPs evoked in lower limb muscles following transcranial magnetic stimulation of motor cortex. Non-painful (3.6 x sensory threshold) percutaneous electrical stimulation was delivered to the sural nerve at conditioning (C)-test (T) intervals of 0-150 msec. MEPs were elicited bilaterally in the tibialis anterior (TA) and lateral gastrocnemius (LG) muscles with and without preceding cutaneous stimulation. Mean MEP amplitudes were facilitated in the ipsilateral TA by 258% (n = 10 of 11), the ipsilateral LG by 275% (n = 7 of 8) and the contralateral TA by 313% (n = 7 of 7) within C-T: 60-100 msec. These results establish that cutaneous afferent stimulation per se does lead to a facilitation of short latency MEPs. In addition, two subjects who were examined at higher stimulation intensities both exhibited late responses (70-95 msec) at C-T: 0-15 msec. These responses, which were independent of the amplitude and appearance of short latency MEPs, suggest a convergence of the cutaneous stimulation with late arriving descending cortical or cortico-bulbospinal inputs to the target motoneuron pool.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D L Wolfe
- Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, Canada
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Hayes KC, Potter PJ, Wolfe DL, Hsieh JT, Delaney GA, Blight AR. 4-Aminopyridine-sensitive neurologic deficits in patients with spinal cord injury. J Neurotrauma 1994; 11:433-46. [PMID: 7837283 DOI: 10.1089/neu.1994.11.433] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
4-Aminopyridine (4-AP) is a potassium channel blocking agent with the ability to restore conduction in demyelinated internodes of axons of the spinal cord. The present investigation sought to obtain electrophysiologic evidence of the effect of 4-AP in ameliorating central conduction deficits in a group of patients (n = 6) with spinal cord injury (SCI). The group was selected on the basis of having temperature-dependent central conduction deficits. 4-AP (24-25 mg total dose) was delivered intravenously at 6 mgh-1 or 15 mgh-1 while somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) were recorded as indices of central conduction. Two patients exhibited marked increases in the amplitude of cortical SEPs, and in one of these, 4-AP brought about a reduced central conduction time from L1 to cortex. Four patients revealed increased amplitude MEPs with concomitant reduction in latency indicative of enhanced conduction in corticospinal or corticobulbospinal pathways. Two of these patients demonstrated increased voluntary motor unit recruitment following 4-AP. Clinical examination revealed reduced spasticity (n = 2), reduced pain (n = 1), increased sensation (n = 1), improved leg movement (n = 3), and restored voluntary control of bowel (n = 1). These results support the hypothesis that 4-AP induces neurologic benefits in some patients with SCI. They are also consistent with the emerging concept that pharmaceutical amelioration of central conduction deficits caused by focal demyelination may contribute to the management of a select group of patients with compressive or contusive SCI.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine & Rehabilitation, Parkwood Hospital, University of Western Ontario, London, Canada
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Hayes KC, Hsieh JT, Potter PJ, Wolfe DL, Delaney GA, Blight AR. Effects of induced hypothermia on somatosensory evoked potentials in patients with chronic spinal cord injury. Paraplegia 1993; 31:730-41. [PMID: 8295782 DOI: 10.1038/sc.1993.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have investigated the effects of mild whole body hypothermia on the amplitude and latency of somatosensory evoked potentials (SEPs) in control subjects (n = 12) and patients (n = 15) with chronic compressive or contusive spinal cord injury (SCI). Mild hypothermia (-1 degree C) was induced by controlled circulation of propylene glycol through a 'microclimate' head and vest garment while reductions in oral and limb temperatures were monitored. Cooling induced a delayed onset and reduced amplitude of tibial nerve SEPs in control subjects. All SCI patients with recordable SEPs (n = 11) showed similarly delayed onset of the cortical response. In contrast to the controls, nine of the 11 SCI patients showed an increase in amplitude of cortical SEPs. In three of these patients the increase in amplitude exceeded 100% of the precooling values. The cooling-induced changes in SEP amplitude and latency reversed on rewarming for both groups. The cooling-induced increases in cortical SEP amplitude support the a priori hypothesis that cooling would enhance central conduction in some SCI patients with conduction deficits due to focal demyelination.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine & Rehabilitation, Parkwood Hospital, London, Ontario, Canada
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Hayes KC, Blight AR, Potter PJ, Allatt RD, Hsieh JT, Wolfe DL, Lam S, Hamilton JT. Preclinical trial of 4-aminopyridine in patients with chronic spinal cord injury. Paraplegia 1993; 31:216-24. [PMID: 8493036 DOI: 10.1038/sc.1993.40] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
4-Aminopyridine (4-AP) is a K+ channel blocking agent that enhances nerve conduction through areas of demyelination by prolonging the duration of the action potential and increasing the safety factor for conduction. We have investigated the effects of 4-AP (24 mg total dose-intravenous) in 6 patients with spinal cord injury (3 complete, 3 incomplete) with the intent of overcoming central conduction block, or slowing, due to demyelination. Vital signs remained stable and only mild side effects were noted. The 3 patients with incomplete injuries all demonstrated enhanced volitional EMG interference patterns and one patient exhibited restored toe movements. The changes were reversed on drug washout. There were no changes in segmental reflex activities. These results are consistent with those obtained from 4-AP trials with animal models of spinal cord injury, showing modest therapeutic benefit attributable to enhanced central conduction.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine & Rehabilitation, Parkwood Hospital, London, Ontario, Canada
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Hayes KC, Allatt RD, Wolfe DL, Kasai T, Hsieh J. Reinforcement of subliminal flexion reflexes by transcranial magnetic stimulation of motor cortex in subjects with spinal cord injury. ACTA ACUST UNITED AC 1992; 85:102-9. [PMID: 1373362 DOI: 10.1016/0168-5597(92)90075-m] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A 20 msec train (500 Hz; 0.1-0.2 msec duration) of percutaneous electrical stimulation (ES) applied to the plantar surface was used to condition muscle responses evoked in tibialis anterior (TA) by transcranial magnetic stimulation of the motor cortex in 8 subjects with traumatic spinal cord injury (SCI). The intensity of conditioning ES was adjusted to just subthreshold for evoking flexion reflexes in TA and was delivered at conditioning-test (C-T) intervals of 15-60 msec prior to cortical stimulation. Four subjects with clinically complete SCI revealed no muscle response to cortical stimulation or following combined subliminal percutaneous ES and cortical stimulation. Four subjects (3 clinically incomplete and 1 complete injury) demonstrated muscle responses with a latency of 70-80 msec time-locked to the percutaneous ES when the conditioning subliminal stimulation was delivered at C-T: 15-40 msec. These responses, resembling suprathreshold flexion reflexes, reflect the convergence of excitatory afferent and cortical inputs and provide evidence of preserved corticospinal innervation to the L4-5 segmental motoneuron or interneuron pools. In 3 of the subjects this preserved corticospinal influence was evident despite absence of motor evoked potentials (MEPs) following cortical stimulation. The effect of the combined electrical and cortical stimulation in yielding suprathreshold flexion reflexes, instead of the facilitated MEPs seen in control subjects, appears to be related to slowed central conduction, prolonged temporal dispersion of the motoneuron facilitation following cortical stimulation and segmental reflex changes associated with disrupted modulation of interneuronal pathways. The results show this conditioning paradigm to be useful in revealing preserved corticospinal innervation in some SCI subjects with absent MEPs.
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Affiliation(s)
- K C Hayes
- Department of Physical Medicine and Rehabilitation, Parkwood Hospital, London, Ont., Canada
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Kasai T, Hayes KC, Wolfe DL, Allatt RD. Afferent conditioning of motor evoked potentials following transcranial magnetic stimulation of motor cortex in normal subjects. ACTA ACUST UNITED AC 1992; 85:95-101. [PMID: 1373371 DOI: 10.1016/0168-5597(92)90074-l] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study determined the effects of percutaneous electrical stimulation of the plantar surface on motor evoked potentials (MEPs) in tibialis anterior (TA) and soleus (SOL) of normal subjects following transcranial magnetic stimulation of motor cortex. The conditioning stimulation consisted of a 20 msec train of electrical pulses (500 Hz; 0.1 msec rectangular) delivered to the medial border of the sole of the foot at an intensity just subthreshold for evoking a flexion reflex. The conditioning (C) stimulation preceded the test (T) cortical stimulation by intervals of 20-130 msec. Magnetic stimulation of motor cortex (Cadwell MES-10) was delivered through a 9.5 cm focal point coil positioned tangential to the scalp and located with the rim over vertex. Five healthy adults served as subjects and each was investigated on at least 2 occasions. At C-T intervals 20-50 msec there was a mild inhibition of MEPs in both TA and SOL. This was followed by marked facilitation (greater than 300%) of MEPs at C-T intervals 50-85 msec in both TA and SOL in all subjects. At longer C-T intervals greater than 110 msec, there was an inhibition of MEPs in TA but not in SOL. Based on the time course of these 3 phases of MEP amplitude modulation, and different stimulation thresholds for each phase, it appears that separate neurophysiological processes underlie each phase of MEP modulation. These observations also suggest that percutaneous electrical stimulation may be useful as a means of enhancing low amplitude or subliminal MEPs in normal subjects or patients with myelopathy.
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Affiliation(s)
- T Kasai
- Department of Physical Medicine and Rehabilitation, Parkwood Hospital, University of Western Ontario, London, Canada
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Abstract
A heart rate radio-transmitter was surgically implanted in the abdomen of a captive adult male polar bear (Thalarctos maritimus), but within five weeks a purulent discharge was observed at the incision site. The transmitter was surgically removed along with many fragments of the fractured encapsulation material. The skin incision healed, but a large hernia remained. Repeated localized trauma to the hernia sac necessitated surgical repair.
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Maher JT, Deniiston JC, Wolfe DL, Cymerman A. Mechanism of the attenuated cardiac response to beta-adrenergic stimulation in chronic hypoxia. J Appl Physiol Respir Environ Exerc Physiol 1978; 44:647-51. [PMID: 649464 DOI: 10.1152/jappl.1978.44.5.647] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A blunting of the chronotropic and inotropic responses of the heart to beta-adrenergic stimulation occurs following chronic exposure to hypobaric hypoxia. To pursue the mechanism(s) involved, observations were made in six intact, conscious goats at sea level and in another six goats maintained in a decompression chamber at 445 Torr (approximately 4,300m) for 10 days (Pao2 = 43 Torr). No significant group differences in cardiac frequency and various indices of myocardial performance (peak dP/dt, time-to-peak dP/dt, Vmax) were demonstrable either before or after cholinergic blockade with intravenous atropine methyl bromide, 1 mg/kg. Following hemodynamic studies, thoracotomies were performed and full-thickness biopsies were obtained from the free wall of each of the cardiac chambers. Neither monoamine oxidase activity nor norepinephrine level of any region of the heart was altered by chronic hypoxia. However, a twofold increase (P less than 0.001) in catechol O-methyltransferase activity above sea-level values was found in both the atria and ventricles of the hypoxic animals. Thus, the attenuation in cardiac responsiveness to beta-adrenoceptor stimulation in chronic hypoxia appears unrelated to the level of vagal activity, but may be attributable to enhanced enzymatic inactivation of catecholamines.
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Maher JT, Manchanda SC, Cymerman A, Wolfe DL, Hartley LH. Cardiovascular responsiveness to beta-adrenergic stimulation and blockade in chronic hypoxia. Am J Physiol 1975; 228:477-81. [PMID: 235220 DOI: 10.1152/ajplegacy.1975.228.2.477] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Previous studies have shown that exposure to high altitude results in an initial increase in heart rate, followed by a return to sea-level values within several days; circulating catecholamines rise progressively during this time. Nine conscious dogs were studied in normoxia (N) and after 10 days' exposure to 445 torr (CH). The mean (plus or minus SE) hematocrit was higher in CH (50 plus or minus 2 vs. 42 plus or minus 1%) while Pa-o2 (53 plus or minus 1 vs. 97 plus or minus 2 torr) and PaCO2 (27 plus or minus 1 vs. 35 plus or minus 1 torr) were lower than in N. A 3.5-fold increase in plasma norepinephrine above the N value was found in CH. Arterial pH, heart rate (HR), and mean femoral arterial pressure (MAP) did not differ significantly in N and CH. Isoproterenol (ISO), 0.5 mug/kg iv, produced an average increase in HR of 92 plus or minus 9 beats/min in N, but only 66 plus or minus 8 beats/min in CH (P smaller than .02). Reduction in MAP after ISO were similar. Pretreatment with propranolol, 0.15 mg/kg iv, reduced HR equally in N and CH without affecting MAP, but diminished the HR response to ISO significantly more in CH than in N. The attenuated chronotropic response to beta-adrenoceptor stimulation following chronic hypobaric hypoxia suggests a relative cardiac refractoriness secondary to an increased level of sympathetic activity.
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Wolfe DL, Forland SC, Benet LZ. Drug transfer across intact rat intestinal mucosa following surgical removal of serosa and muscularis externa. J Pharm Sci 1973; 62:200-5. [PMID: 4686389 DOI: 10.1002/jps.2600620203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Finocchio EJ, Hales WS, Wolfe DL. Persistent median wall of the Mullerian duct system in a two-year-old filly. Vet Med Small Anim Clin 1968; 63:622. [PMID: 5185605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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