Gender differences in PTSD severity and pain outcomes: Baseline results from the LAMP trial.

BACKGROUND: Post-traumatic stress disorder (PTSD) and chronic pain are highly prevalent comorbid conditions. Veterans dually burdened by PTSD and chronic pain experience more severe outcomes compared to either disorder alone. Few studies have enrolled enough women Veterans to test gender differences in pain outcomes [catastrophizing, intensity, interference] by the severity of PTSD symptoms. AIM: Examine gender differences in the association between PTSD symptoms and pain outcomes among Veterans enrolled in a chronic pain clinical trial. METHODS: Participants were 421 men and 386 women Veterans with chronic pain who provided complete data on PTSD symptoms and pain outcomes. We used hierarchical linear regression models to examine gender differences in pain outcomes by PTSD symptoms. RESULTS: Adjusted multivariable models indicated that PTSD symptoms were associated with higher levels of pain catastrophizing (0.57, 95% CI [0.51, 0.63]), pain intensity (0.30, 95% CI [0.24, 0.37]), and pain interference (0.46, 95% CI [0.39, 0.52]). No evidence suggesting gender differences in this association were found in either the crude or adjusted models (all interaction p-values<0.05). CONCLUSION: These findings may reflect the underlying mutual maintenance of these conditions whereby the sensation of pain could trigger PTSD symptoms, particularly if the trauma and pain are associated with the same event. Clinical implications and opportunities testing relevant treatments that may benefit both chronic pain and PTSD are discussed.

Exploring Gender Differences in Veterans in a Secondary Analysis of a Randomized Controlled Trial of Mindfulness for Chronic Pain.

Background: Although studies have documented higher rates of chronic pain among women Veterans compared to men Veterans, there remains a lack of comprehensive information about potential contributors to these disparities. Materials and Methods: This study examined gender differences in chronic pain and its contributors among 419 men and 392 women Veterans, enrolled in a mindfulness trial for chronic pain. We conducted descriptive analyses summarizing distributions of baseline measures, obtained by survey and through the electronic health record. Comparisons between genders were conducted using chi-square tests for categorical variables and t-tests for continuous measures. Results: Compared to men, women Veterans were more likely to have chronic overlapping pain conditions and had higher levels of pain interference and intensity. Women had higher prevalence of psychiatric and sleep disorder diagnoses, greater levels of depression, anxiety, post-traumatic stress disorder, fatigue, sleep disturbance, stress and pain catastrophizing, and lower levels of pain self-efficacy and participation in social roles and activities. However, women were less likely to smoke or have a substance abuse disorder and used more nonpharmacological pain treatment modalities. Conclusion: Among Veterans seeking treatment for chronic pain, women differed from men in their type of pain, had greater pain intensity and interference, and had greater prevalence and higher levels of many known biopsychosocial contributors to pain. Results point to the need for pain treatment that addresses the comprehensive needs of women Veterans.Clinical Trial Registration Number: NCT04526158. Patient enrollment began on December 4, 2020.

Effects of Real-Time Pressure Map Feedback on Confidence in Pressure Management in Wheelchair Users With Spinal Cord Injury: Pilot Intervention Study.

BACKGROUND: Wheelchair users with a spinal cord injury (SCI) are at a high risk for developing pressure injuries (PIs). Performing weight shifts is a primary method of pressure management for PI prevention; however, individuals with SCI may lack confidence in their abilities to perform adequate pressure relief due to their lack of sensation. Real-time seat interface pressure mapping feedback may provide partial substitution for sensory feedback such that an individual's confidence is improved. OBJECTIVE: We aim to examine how confidence for pressure management by wheelchair users with SCI was impacted by providing access to real-time, on-demand seat interface pressure mapping feedback. METHODS: Adults with SCI (N=23) completed self-efficacy questions addressing confidence around 4 factors related to performing weight shifts in this longitudinal, repeated-measures study. We evaluated the impact of providing standard PI prevention education and access to live pressure map feedback on confidence levels for performing weight shifts. RESULTS: Access to live pressure map feedback while learning how to perform weight shifts resulted in significantly higher confidence about moving far enough to relieve pressure at high-risk areas. Confidence for adhering to the recommended weight shift frequency and duration was not significantly impacted by in-clinic education or use of pressure map feedback. Confidence that performing weight shifts reduces PI risk increased most following education, with slight additional increase when pressure map feedback was added. CONCLUSIONS: Access to live pressure mapping feedback improves confidence about performing weight shifts that relieve pressure when provided in the clinical setting and demonstrates potential for the same in the home. This preliminary exploration of a smartphone-based pressure mapping intervention highlights the value of access to continuous pressure mapping feedback to improve awareness and confidence for managing pressure. TRIAL REGISTRATION: ClinicalTrials.gov NCT03987243; https://clinicaltrials.gov/study/NCT03987243.

Feasibility testing of a novel prosthetic socket sensor system.

PURPOSE: Poorly fitting prosthetic sockets contribute to decreased quality of life, health, and well-being for persons with amputations. Therefore, improved socket fit is a high clinical priority. METHODS: In this study, we describe the design and testing of a novel sensor system that can be incorporated into a prosthetic socket to measure distal end weight bearing in the socket and can alert a prosthesis user if poor socket fit is suspected. We present the results of testing this device with three Veterans who were new prosthesis users and three Veterans who were experienced prosthesis users. RESULTS AND CONCLUSIONS: We collected sensor data during walking trials while participants wore varying numbers of sock plies and qualitative feedback on the design of the socket fit sensor system. For analysis, peak sensor measurements during walking cycles were identified and combined with socket fit data (i.e., a clinician-determined level of "good," "too tight," or "too loose" and the number of sock ply worn each trial). We found consistent relationships between peak sensor measurements and socket fit in our sample. Also, all users expressed an interest in the device, highlighting its potential benefits during early prosthesis training.Implications for RehabilitationEnsuring socket fit is challenging for many prosthesis users.A novel wearable sensor system can be used to identify socket fit issues for some prosthesis users.This type of system could be most helpful for new prosthesis users and those with sensory and cognitive challenges.

Supine arm cycling during the post-flap recovery period for persons with spinal cord injuries: The multi-purpose arm cycle ergometer (M-PACE) safety and pilot testing.

OBJECTIVE: To describe how using a supine arm cycle ergometer can safely reduce deconditioning experienced by patients with spinal cord injury or disorder (SCI/D) during their four to six weeks of complete bed rest after surgery to close a stage 4 pressure injury. DESIGN: This pilot project used a newly designed arm cycle ergometer (known as the M-PACE) that extends over the bed, allowing a patient to lie completely supine while exercising. SETTING: The M-PACE was designed and built at the Minneapolis Veterans Affairs Health Care System (MVAHCS) and pilot tested at the MVAHCS SCI/D Center. PARTICIPANTS: Patients with SCI/D, recovering from flap surgery and deemed appropriate to use the arm cycle ergometer were enrolled in the pilot study (n = 47). OUTCOME MEASURES: A pre-post six-minute arm test (6MAT), a proxy for conditioning, was conducted on a subset (n = 15) of participants before and after the supine cycling exercise training program. Participants' rating of perceived exertion (RPE) scores were collected at cessation of each 6MAT. Participants gave feedback on their perception of using the M-PACE. RESULTS/CONCLUSIONS: The 6MAT RPE was significantly reduced after training with the M-PACE while on bed rest (P = 0.003). Also, significantly more rotations were performed after completing the training program (P = 0.02). Further, study participants who accessed the M-PACE found using it helped offset the tedium of laying supine during flap surgery recovery. The differences in the 6MAT pre- to post measures indicate the M-PACE should be further studied for offsetting the normal deconditioning that occurs with extended bedrest.

Strategies for graded motor imagery for clients with phantom limb pain and cognitive impairment.

BACKGROUND: Individuals with amputations often experience phantom limb pain (PLP) that can limit their participation in rehabilitation, prosthesis training, desired activities, and roles. One nonpharmacological rehabilitation intervention for PLP is graded motor imagery (GMI). There are several components to GMI, including right/left discrimination or laterality, motor imagery, sensory retraining, and mirror therapy. Successful implementation of GMI requires a range of cognitive skills, such as attention span, working memory, abstract reasoning, and planning. For individuals with PLP who concurrently display cognitive impairments, GMI protocols can be adapted using strategies derived from clinical practice. OBJECTIVES: The purpose of this technical clinical report was to discuss the application of clinically implemented cognitive compensation techniques to GMI instruction. STUDY DESIGN: Not applicable. METHODS: Clinical expert opinion to explore adaptations for GMI. TECHNIQUE: Graded motor imagery can be an effective tool for pain treatment; however, some clients may need greater clinician support due to existing cognitive difficulties. RESULTS: For clients to be successful, active engagement in learning about and implementing GMI techniques is necessary. CONCLUSIONS: When serving the lifetime amputation care needs of patients with cognitive deficits, we find that targeted learning strategies and accommodations can be helpful when introducing GMI concepts and skill development. Enhanced patient education techniques support client learning.

Visualization of user interactions with a pressure mapping mobile application for wheelchair users at risk for pressure injuries.

Pressure injuries for individuals with spinal cord injuries (SCI) are correlated with mortality and are a leading cause for rehospitalizations. The Assisted Weight Shift (AW-Shift©) is a mobile pressure mapping application designed to provide users with a live map view and reminders to perform weight shifts. Novel visualization techniques were used to understand daily distributions of user interaction wit h AW-Shift©. The date and time of system interactions were recorded for six participants with SCI over 7 days (five males/one female, five manual users/one power user, 55.3 ± 17.3 years old, 10.6 ± 6.5 years since injury). Circular frequency plots were created to visualize the time and frequency participants brought the app to the foreground of their phone and received alerts and reminders to complete weight shifts. While some participants used the system regularly throughout the day, others primarily used it before 8am; highlighting the system's importance for regular spot checks and morning wheelchair setup. Participant adherence to weight shift reminders was low suggesting the live pressure map may be more useful. Circular frequency plots can be used by clinicians to more easily review large amounts of patient data. Future work will investigate raw pressure mat data and create a closed-loop weight shift detection algorithm.

Age Predicts Older Adults' Driving Self-Regulation but Not Dangerous Driving Behaviors after Controlling for Executive Function.

OBJECTIVES: The aim of the study was to examine the unique contributions of age to objectively measure driving frequency and dangerous driving behaviors in healthy older adults after adjusting for executive function (EF). METHOD: A total of 28 community-dwelling older adults (mean age = 82.0 years, standard deviation [SD] = 7.5) without dementia who were in good physical health and enrolled in a longitudinal aging study completed several EF and clinical self-report measures at baseline. Participants subsequently had a sensor installed in their vehicle for a mean of 208 (SD = 38, range = 127-257) days. RESULTS: Participants drove for an average of 54 min per day. Mixed-effects models indicated that after controlling for EF, older age was associated with less time driving per day, decreased number of trips, and less nighttime driving. Age was not associated with hard brakes or hard accelerations. DISCUSSION: After accounting for EF, greater age is associated with higher driving self-regulation but not dangerous driving behaviors in healthy older adults. Future studies should recruit larger samples and collect sensor-measured driving data over a more extended time frame to better determine how and why these self-regulation changes take place.

Subtle Changes in Medication-taking Are Associated With Incident Mild Cognitive Impairment.

INTRODUCTION: Medication-taking is a routine instrumental activity of daily living affected by mild cognitive impairment (MCI) but difficult to measure with clinical tools. This prospective longitudinal study examined in-home medication-taking and transition from normative aging to MCI. METHODS: Daily, weekly, and monthly medication-taking metrics derived from an instrumented pillbox were examined in 64 healthy cognitively intact older adults (Mage=85.5 y) followed for a mean of 2.3 years; 9 transitioned to MCI during study follow-up. RESULTS: In the time up to and after MCI diagnosis, incident MCI participants opened their pillbox later in the day (by 19 min/mo; ß=0.46, P<0.001) and had increased day-to-day variability in the first pillbox opening over time (by 4 min/mo) as compared with stable cognitively intact participants (ß=4.0, P=0.003). DISCUSSION: Individuals who transitioned to MCI opened their pillboxes later in the day and were more variable in their medication-taking habits. These differences increased in the time up to and after diagnosis of MCI. Unobtrusive medication-taking monitoring is an ecologically valid approach for identifying early activity of daily living changes that signal transition to MCI.

Learning to Apply Mindfulness to Pain (LAMP): Design for a Pragmatic Clinical Trial of Two Mindfulness-Based Interventions for Chronic Pain.

BACKGROUND: Mindfulness-based interventions (MBIs) are evidence-based nonpharmacological treatments for treating chronic pain. However, the predominant MBI, mindfulness-based stress reduction, has features that pose significant implementation barriers. OBJECTIVES: This study will test two approaches to delivering MBIs for improving Veterans' chronic pain and mental health comorbidities. These two approaches address key implementation barriers. METHODS: We will conduct a four-site, three-arm pragmatic randomized controlled trial, Learning to Apply Mindfulness to Pain (LAMP), to test the effectiveness of two MBIs at improving pain and mental health comorbidities. Mobile+Group LAMP consists of prerecorded modules presented by a mindfulness instructor that are viewed in an online group setting and interspersed with discussions led by a facilitator. Mobile LAMP consists of the same prerecorded modules but does not include a group component. We will test whether either of these MBIs will be more effective than usual care at improving chronic pain and whether the Mobile+Group LAMP will be more effective than Mobile LAMP at improving chronic pain. Comparisons for the primary hypotheses will be conducted with continuous outcomes (Brief Pain Inventory interference score) repeated at 10 weeks, 6 months, and 12 months. The secondary hypotheses are that Mobile+Group LAMP and Mobile LAMP will be more effective than usual care at improving secondary outcomes (e.g., post-traumatic stress disorder, depression). We will also confirm the comparisons for the primary and secondary hypotheses in gender-specific strata. IMPLICATIONS: This trial is expected to result in two approaches for delivering MBIs that will optimize engagement, adherence, and sustainability and be able to reach large numbers of Veterans.

Bimodal ankle-foot prosthesis for enhanced standing stability.

Previous work suggests that to restore postural stability for individuals with lower-limb amputation, ankle-foot prostheses should be designed with a flat effective rocker shape for standing. However, most commercially available ankle-foot prostheses are designed with a curved effective rocker shape for walking. To address the demands of both standing and walking, we designed a novel bimodal ankle-foot prosthesis that can accommodate both functional modes using a rigid foot plate and an ankle that can lock and unlock. The primary objective of this study was to determine if the bimodal ankle-foot system could improve various aspects of standing balance (static, dynamic, and functional) and mobility in a group of Veterans with lower-limb amputation (n = 18). Standing balance was assessed while subjects completed a series of tests on a NeuroCom Clinical Research System (NeuroCom, a Division of Natus, Clackamas, OR), including a Sensory Organization Test, a Limits of Stability Test, and a modified Motor Control Test. Few statistically significant differences were observed between the locked and unlocked ankle conditions while subjects completed these tests. However, in the absence of visual feedback, the locked bimodal ankle appeared to improve static balance in a group of experienced lower-limb prosthesis users whose PLUS-M mobility rating was higher than approximately 73% of the sample population used to develop the PLUS-M survey. Given the statistically significant increase in mean equilibrium scores between the unlocked and locked conditions (p = 0.004), future testing of this system should focus on new amputees and lower mobility users (e.g., Medicare Functional Classification Level K1 and K2 prosthesis users). Furthermore, commercial implementation of the bimodal ankle-foot system should include a robust control system that can automatically switch between modes based on the user's activity.

Microclimate evaluation of strap-based wheelchair seating systems for persons with spinal cord injury: A pilot study.

STUDY PURPOSE: The purpose of this pilot study was to assess microclimate characteristics of two versions of a strap-based wheelchair seating system (perforated and solid straps) and to conduct preliminary microclimate comparisons of subjects' current wheelchair seating systems. MATERIALS AND METHODS: In this pilot study, the microclimate properties of two variations (solid and perforated) of a strap-based seating system were compared with two commonly used seating systems. Six subjects sat on three different seating systems each for 100-min test periods, while temperature and relative humidity were measured with a single sensor adjacent to the skin-seat interface. Additionally, thermal images of the seat interface were collected before and after each test period. RESULTS: The thermal images revealed that the maximum surface temperature of the solid-strap-based seating system was significantly lower than the other seating systems, -1.21 °C. (95% CI -2.11 to -0.30, p = 0.02), immediately following transfer out of the seat. Five minutes after transferring out of the seat, the perforated-strap seat was significantly cooler than the other seats -0.94 °C. (95% CI -1.59 to -0.30), p = 0.01, as was the solid-strap-based seat, -1.66 °C. (95% CI -2.69 to -0.63), p = 0.01. There were no significant differences in interface temperature or relative humidity measured with the single sensor near the skin-seat interface. CONCLUSION: This pilot study offers preliminary evidence regarding the microclimate of the strap-based seating systems compared with other common seating systems. Clinically, the strap-based seating system may offer another option for those who struggle with microclimate management.

Pilot study of strap-based custom wheelchair seating system in persons with spinal cord injury.

Custom wheelchair seats can be used to help prevent pressure ulcers in individuals with spinal cord injury. In this study, a strap-based system was evaluated in three Veterans with spinal cord injury. Interface pressure distributions were measured after transfers, wheeling, and pressure relief maneuvers and after fittings by three different therapists. We found that pressure distribution measures were not generally affected after transfers and wheeling using the strap-based wheelchair and that pressure relief maneuvers were able to be performed. Additionally, all therapists were able to customize the wheelchair seat to clinically acceptable levels in 4 to 40 min for the three subjects. Future studies can test the long-term effects of using the strap-based wheelchair seat and identifying individuals that would most benefit from a rapidly customizable wheelchair seat.

Nanowires precisely grown on the ends of microwire electrodes permit the recording of intracellular action potentials within deeper neural structures.

AIMS: Nanoelectrodes are an emerging biomedical technology that can be used to record intracellular membrane potentials from neurons while causing minimal damage during membrane penetration. Current nanoelectrode designs, however, have low aspect ratios or large substrates and thus are not suitable for recording from neurons deep within complex natural structures, such as brain slices. MATERIALS & METHODS: We describe a novel nanoelectrode design that uses nanowires grown on the ends of microwire recording electrodes similar to those frequently used in vivo. RESULTS & DISCUSSION: We demonstrate that these nanowires can record intracellular action potentials in a rat brain slice preparation and in isolated leech ganglia. CONCLUSION: Nanoelectrodes have the potential to revolutionize intracellular recording methods in complex neural tissues, to enable new multielectrode array technologies and, ultimately, to be used to record intracellular signals in vivo.

Wireless communication with implanted medical devices using the conductive properties of the body.

Many medical devices that are implanted in the body use wires or wireless radiofrequency telemetry to communicate with circuitry outside the body. However, the wires are a common source of surgical complications, including breakage, infection and electrical noise. In addition, radiofrequency telemetry requires large amounts of power and results in low-efficiency transmission through biological tissue. As an alternative, the conductive properties of the body can be used to enable wireless communication with implanted devices. In this article, several methods of intrabody communication are described and compared. In addition to reducing the complications that occur with current implantable medical devices, intrabody communication can enable novel types of miniature devices for research and clinical applications.

An inside look at hippocampal silent cells.

Hippocampal pyramidal cells can be divided into place cells, which fire action potentials when an animal is in specific locations, and silent cells, which are not spatially selective. In this issue of Neuron, Epsztein et al. find intracellular differences between place and silent cells by using whole-cell recordings in freely moving rats.

IBCOM (intra-brain communication) microsystem: wireless transmission of neural signals within the brain.

We report our preliminary work to explore a new method of signal transmission for bio-implantable microsystems. Intra-brain communication or IBCOM is a wireless signal transmission method that uses the brain itself as a conductive medium to transmit the data and commands between neural implants and data processing systems outside the brain. Two miniaturized IBCOM (micro-IBCOM) CMOS chips were designed and fabricated for an in vivo test bed to transmit two prerecorded neural signals at different binary frequency shift keying (BFSK) carrier frequencies to validate the feasibility of IBCOM concept. The chips were packaged for full implantation in a rat brain except for external power delivery. The original neural signal waveforms were successfully recovered after being transmitted between two platinum electrodes separated by 15 mm with transmission power less than 650 pJ/bit for the CMOS implementation.

Creating low-impedance tetrodes by electroplating with additives.

A tetrode is a bundle of four microwires that can record from multiple neurons simultaneously in the brain of a freely moving animal. Tetrodes are usually electroplated to reduce impedances from 2-3 MΩ to 200-500 kΩ (measured at 1 kHz), which increases the signal-to-noise ratio and allows for the recording of small amplitude signals. Tetrodes with even lower impedances could improve neural recordings but cannot be made using standard electroplating methods without shorting. We were able to electroplate tetrodes to 30-70 kΩ by adding polyethylene glycol (PEG) or multi-walled carbon nanotube (MWCNT) solutions to a commercial gold-plating solution. The MWCNTs and PEG acted as inhibitors in the electroplating process and created large-surface-area, low-impedance coatings on the tetrode tips.