The Graph-DCK Scale: a measure of dorsal column function after spinal cord injury.

STUDY DESIGN: Cohort/psychometric study. OBJECTIVES: Assessment of dorsal column medial lemniscus (DCML) function is important for the clinical evaluation of people with spinal cord injury (SCI) because it provides useful information to guide rehabilitation and for prognosticating outcomes. For example, research suggests that damage to the DCML pathway may be associated with neuropathic pain after SCI. Tests for graphesthesia and directional cutaneous kinesthesia (DCK) are commonly used clinically to assess DCML function. However, the reliability and validity of these assessments in people with SCI have not been investigated. Moreover, there is a poor consistency between studies in the methodology of graphesthesia and DCK assessment. The purpose of this study was to determine the psychometric properties of the Graph-DCK Scale, which is a simple and potentially useful scale for assessing graphesthesia and DCK. The Graph-DCK Scale does not require expensive equipment and it takes less than 5 min to administer. SETTING: A university-based laboratory in Miami, FL, USA. METHODS: Sixty-seven people with chronic SCI and neuropathic pain were included in this study. The Graph-DCK Scale and vibration detection were measured twice in each participant, with a two- to four-week period between measurement sessions. RESULTS: The scale demonstrated an excellent internal consistency (Cronbach's alpha > 0.90) and test-retest reliability (ICC values > 0.80). Further, convergent validity was supported by moderate and significant positive correlations to vibration detection (r values > 0.40). CONCLUSION: The Graph-DCK Scale is quick and easy to administer, and it provides a reliable and valid assessment of DCML function in people with SCI. SPONSORSHIP: Craig Neilsen Foundation.

Paraquat neurotoxicity is mediated by the dopamine transporter and organic cation transporter-3.

The herbicide paraquat (PQ) has increasingly been reported in epidemiological studies to enhance the risk of developing Parkinson's disease (PD). Furthermore, case-control studies report that individuals with genetic variants in the dopamine transporter (DAT, SLC6A) have a higher PD risk when exposed to PQ. However, it remains a topic of debate whether PQ can enter dopamine (DA) neurons through DAT. We report here a mechanism by which PQ is transported by DAT: In its native divalent cation state, PQ(2+) is not a substrate for DAT; however, when converted to the monovalent cation PQ(+) by either a reducing agent or NADPH oxidase on microglia, it becomes a substrate for DAT and is accumulated in DA neurons, where it induces oxidative stress and cytotoxicity. Impaired DAT function in cultured cells and mutant mice significantly attenuated neurotoxicity induced by PQ(+). In addition to DAT, PQ(+) is also a substrate for the organic cation transporter 3 (Oct3, Slc22a3), which is abundantly expressed in non-DA cells in the nigrostriatal regions. In mice with Oct3 deficiency, enhanced striatal damage was detected after PQ treatment. This increased sensitivity likely results from reduced buffering capacity by non-DA cells, leading to more PQ(+) being available for uptake by DA neurons. This study provides a mechanism by which DAT and Oct3 modulate nigrostriatal damage induced by PQ(2+)/PQ(+) redox cycling.

Massage Therapy: A Person-Centred Approach to Chronic Pain.

Person-centred care is an emergent movement within evidence-based medicine that has the potential to transform the health care system. Person-centred care is a collaborative approach in which health care professionals partner with patients to co-design and deliver personalized care with a focus on physical comfort, emotional well-being, and patient empowerment. By embracing person-centred care through two-way communication, patient engagement, and self-management strategies, massage therapists have the potential to further reduce suffering associated with chronic pain in our society.

Spasticity and Pain after Spinal Cord Injury: Impact on Daily Life and the Influence of Psychological Factors.

BACKGROUND: Spasticity and pain frequently co-occur in persons with spinal cord injury (SCI), yet, how these sequelae interact in daily life is unclear. Additionally, little is known about how psychological factors relate to the perception of spasticity and its impacts on daily life. OBJECTIVES: (1) Characterize relationships between spasticity and chronic pain with regard to perceived severity, difficulty dealing, and life interference. (2) Determine the extent to which perceived spasticity severity and physiological, psychological, and pain-related factors contribute to impacts of spasticity on daily life (difficulty in dealing, life interference). (3) Determine the effects of painful spasticity on aspects of chronic pain and spasticity (severity, life interference, interference with sleep, and spasm duration). DESIGN: Observational study. SETTING: University laboratory. PARTICIPANTS: Twenty participants with SCI and lower extremity spasticity. METHODS: Measures included International SCI Pain Basic Data Set, Pain and Spasticity Inventories, Difficulty Dealing with Pain/Spasticity, SCI-Spasticity Evaluation Tool, Connor-Davidson Resilience and Moorong Self-Efficacy Scales, Spinal Cord Assessment Tool for Spastic Reflexes, spasm duration, and injury-related and demographic factors. Bivariate correlations, multiple regression analyses, and pairwise comparisons were performed. RESULTS: Spasticity and chronic pain were directly related, with respect to perceived severity, difficulty dealing, and life interference (rho = 0.514-0.673, P < .05). Shorter injury duration, greater perceived spasticity severity, and greater difficulty dealing with pain explained 61% of variance in difficulty dealing with spasticity. Greater perceived spasticity severity and lower resilience explained 72% of variance in life interference of spasticity. Spasm duration was not significantly associated with perceived spasticity severity. Participants with painful spasticity had significantly greater chronic pain severity (P = .02) and sleep-related impact of spasticity (P = .03) than participants without painful spasticity. CONCLUSIONS: Perceived severity of spasticity, injury duration, ability to deal with chronic pain, resilience, and painful spasms appear to play important roles in the negative impacts of spasticity on life after SCI. LEVEL OF EVIDENCE: III.

Impact of spasticity on transfers and activities of daily living in individuals with spinal cord injury.

CONTEXT/OBJECTIVE: For persons with spinal cord injury, spasticity commonly interferes with activities of daily living such as transfers. Electromyography can be used to objectively measure muscle spasms during transfers, but how electromyographic measures relate to the impact spasticity has on life, or to clinically-rated spasticity, is unclear. We aimed to characterize relationships among spasm duration and magnitude, impact of spasticity on daily life, and a clinical measure of extensor spasticity, as well as to determine reliability of the electromyographic measures. DESIGN: Participants (N=19) underwent electromyographic measurements of involuntary muscle activity (spasm duration and magnitude) evoked in quadriceps muscles during transfers on two days. Impact of spasticity on daily life was measured with the Spinal Cord Injury Spasticity Evaluation Tool. Clinically-rated spasticity severity was measured with the Spinal Cord Assessment Tool for Spastic reflexes. RESULTS: No significant associations were found between impact of spasticity and spasm duration, spasm magnitude, or clinical extensor spasticity score. Absolute and normalized spasm duration were positively associated with clinical extensor spasticity score (rho=0.510-0.667, P < 0.05). Spasm measures during transfers had good to excellent day-to-day reliability (rho=0.656-0.846, P < 0.05). CONCLUSIONS: Electromyographic and clinical measures of involuntary activity in the lower extremity do not significantly relate to perceived impact of spasticity on daily life. However, quadriceps spasm duration during transfers is related to clinically-rated extensor spasticity. Electromyography is a reliable method of quantifying quadriceps spasms during transfers. Future investigations should identify factors that influence the impact of spasticity on life, which may help direct treatment strategies to reduce problematic impact.

Multidimensional Neuropathic Pain Phenotypes after Spinal Cord Injury.

Identifying clinical neuropathic pain phenotypes is a first step to better understand the underlying pain mechanisms after spinal cord injury (SCI). The primary purpose of the present study was to characterize multidimensional neuropathic pain phenotypes based on quantitative sensory testing (QST), pain intensity, and utilization of catastrophizing coping strategies. Thermal perception, thermal pain, and vibratory perception thresholds were assessed above and below the level of injury (LOI) in 101 persons with SCI and neuropathic pain, 18 persons with SCI and no neuropathic pain, and 50 able-bodied, pain-free controls. Cluster analysis of QST z-scores below the LOI, pain intensity ratings, and the Coping Strategies Questionnaire (CSQ) catastrophizing subscale scores in subjects with neuropathic pain resulted in two phenotypes: severe neuropathic pain (SNP) with greater pain intensity (7.39 ± 1.57) and thermal and vibratory sensitivity compared with the moderate neuropathic pain (MNP; 5.40 ± 1.43). A factor analysis including all CSQ subscales, the Neuropathic Pain Symptom Inventory (NPSI) total score, and thermal pain sensitivity above and below the LOI resulted in three factors: (1) adaptive pain coping including increasing activities, diverting attention, and reinterpreting pain sensations; (2) catastrophizing, neuropathic pain, and thermal sensitivity including greater NPSI total score, thermal pain sensitivity below the LOI, and catastrophizing; and (3) general pain sensitivity including greater thermal pain sensitivity above the LOI and lower catastrophizing. Our results suggest that neuropathic pain symptom severity post-SCI is significantly associated with residual spinothalamic tract function below the LOI and catastrophizing pain coping.

Priming for Improved Hand Strength in Persons with Chronic Tetraplegia: A Comparison of Priming-Augmented Functional Task Practice, Priming Alone, and Conventional Exercise Training.

Many everyday tasks cannot be accomplished without adequate grip strength, and corticomotor drive to the spinal motoneurons is a key determinant of grip strength. In persons with tetraplegia, damage to spinal pathways limits transmission of signals from motor cortex to spinal motoneurons. Corticomotor priming, which increases descending drive, should increase corticospinal transmission through the remaining spinal pathways resulting in increased grip strength. Since the motor and somatosensory cortices share reciprocal connections, corticomotor priming may also have potential to influence somatosensory function. The purpose of this study was to assess changes in grip (precision, power) force and tactile sensation associated with two different corticomotor priming approaches and a conventional training approach and to determine whether baseline values can predict responsiveness to training. Participants with chronic (≥1 year) tetraplegia (n = 49) were randomized to one of two corticomotor priming approaches: functional task practice plus peripheral nerve somatosensory stimulation (FTP + PNSS) or PNSS alone, or to conventional exercise training (CET). To assess whether baseline corticospinal excitability (CSE) is predictive of responsiveness to training, in a subset of participants, we assessed pre-intervention CSE of the thenar muscles. Participants were trained 2 h daily, 5 days/week for 4 weeks. Thirty-seven participants completed the study. Following intervention, significant improvements in precision grip force were observed in both the stronger and weaker hand in the FTP + PNSS group (effect size: 0.51, p = 0.04 and 0.54, p = 0.03, respectively), and significant improvements in weak hand precision grip force were associated with both PNSS and CET (effect size: 0.54, p = 0.03 and 0.75, p = 0.02, respectively). No significant changes were observed in power grip force or somatosensory scores in any group. Across all groups, responsiveness to training as measured by change in weak hand power grip force was correlated with baseline force. Change in precision grip strength was correlated with measures of baseline CSE. These findings indicate that corticomotor priming with FTP + PNSS had the greatest influence on precision grip strength in both the stronger and weaker hand; however, both PNSS and CET were associated with improved precision grip strength in the weaker hand. Responsiveness to training may be associated with baseline CSE.