Featured Articles #005: Stroke, Hyperkyphosis and Geriatric Low Back Pain
Previously featured articles #005: December 29, 2021 – February 15, 2022.
Critical Period After Stroke Study (CPASS): A phase II clinical trial testing an optimal time for motor recovery after stroke in humans
Abstract
Background
Restoration of human brain function after injury is a signal challenge for translational neuroscience. Rodent stroke recovery studies identify an optimal or sensitive period for intensive motor training after stroke: near-full recovery is attained if task-specific motor training occurs during this sensitive window. We extended these findings to adult humans with stroke in a randomized controlled trial applying the essential elements of rodent motor training paradigms to humans.
Methods
Stroke patients were adaptively randomized to begin 20 extra hours of self-selected, task-specific motor therapy at ≤30 d (acute), 2 to 3 mo (subacute), or ≥6 mo (chronic) after stroke, compared with controls receiving standard motor rehabilitation. Upper extremity (UE) impairment assessed by the Action Research Arm Test (ARAT) was measured at up to five time points. The primary outcome measure was ARAT recovery over 1 y after stroke.
Results
By 1 y we found significantly increased UE motor function in the subacute group compared with controls (ARAT difference = +6.87 ± 2.63, P = 0.009). The acute group compared with controls showed smaller but significant improvement (ARAT difference = +5.25 ± 2.59 points, P = 0.043). The chronic group showed no significant improvement compared with controls (ARAT = +2.41 ± 2.25, P = 0.29). Thus task-specific motor intervention was most effective within the first 2 to 3 mo after stroke.
Conclusion
The similarity to rodent model treatment outcomes suggests that other rodent findings may be translatable to human brain recovery. These results provide empirical evidence of a sensitive period for motor recovery in humans.
Step Number and Aerobic Minute Exercise Prescription and Progression in Stroke: A Roadmap
Abstract
Background
While higher therapeutic intensity improves motor recovery after stroke, translating findings from successful studies is challenging without clear exercise intensity targets. We show in the DOSE trial more than double the steps and aerobic minutes within a session can be achieved compared with usual care and translates to improved long-term walking outcomes.
Objective
We modeled data from this successful higher intensity multi-site RCT to develop targets for prescribing and progressing exercise for varying levels of walking impairment after stroke.
Methods
In twenty-five individuals in inpatient rehabilitation, twenty sessions were monitored for a total of 500 one-hour physical therapy sessions. For the 500 sessions, step number and aerobic minute progression were modeled using linear mixed effects regression. Using formulas from the linear mixed effects regression, targets were calculated.
Results
The model for step number included session number and baseline walking speed, and for aerobic minutes, session number and age. For steps, there was an increase of 73 steps per session. With baseline walking speed, for every 0.1 m/s increase, a corresponding increase of 302 steps was predicted. For aerobic minutes, there was an increase of .56 minutes of aerobic activity (ie, 34 seconds) per session. For every year increase in age, a decrease of .39 minutes (ie, 23 seconds) was predicted.
Conclusion
Using data associated with better walking outcomes, we provide step number and aerobic minute targets that future studies can cross-validate. As walking speed and age are collected at admission, these models allow for uptake of routine measurement of therapeutic intensity..
Abstract
Background
We reviewed exercise trials in men and women ≥ 45 years with hyperkyphosis at the baseline and performed meta-analyses for kyphosis and health-related outcomes.
Methods
Multiple databases were searched to May 2020. Randomized controlled trials (RCTs), non-RCT, and pre-post intervention studies that had at least one group with a mean kyphosis angle of at least 40° at the baseline were included.
Results
Twenty-four studies were included. Exercise or physical therapy improved kyphosis outcomes (SMD − 0.31; 95% confidence intervals [CI] − 0.46, − 0.16; moderate certainty evidence), back extensor muscle strength (MD 10.51 N; 95% CI 6.65, 14.38; very low certainty evidence), and endurance (MD 9.76 s; 95% CI 6.40, 13.13; low certainty evidence). Meta-analyses showed improvements in health-related quality of life (HRQoL) (SMD 0.21; 95% CI 0.06, 0.37; moderate certainty of evidence), general pain (MD − 0.26; 95% CI − 0.39, − 0.13; low certainty of evidence), and performance on the timed up and go (TUG) test (MD − 0.28 s; 95% CI − 0.48, − 0.08; very low certainty of evidence). The effects on the rate of falls (incidence rate ratio [IRR] 1.15; 95% CI 0.64, 2.05; low certainty evidence) or minor adverse events (IRR 1.29; 95% CI 0.95, 1.74; low certainty evidence) are uncertain. No serious adverse events were reported in the included studies.
Conclusion
Interventions targeting hyperkyphosis may improve kyphosis outcomes in adults with hyperkyphosis.
Classification of Geriatric Low Back Pain Based on Hip Characteristics With a 12-Month Longitudinal Exploration of Clinical Outcomes: Findings From Delaware Spine Studies
Abstract
Objective
The purpose of this study is to identify geriatric chronic low back pain (LBP) subgroups based on the presence of potentially modifiable hip impairments, using Latent Variable Mixture Modeling (LVMM), and to examine the prospective relationship between these subgroups and key outcomes over time.
Methods
Baseline, 3-month, 6-month, and 12-month data were collected from a prospective cohort of 250 community-dwelling older adults with chronic LBP. Comprehensive hip (symptoms, strength, range of motion, and flexibility), LBP (intensity and disability), and mobility function (gait speed and 6-Minute Walk Test) examinations were performed at each timepoint. Baseline hip measures were included in LVMM; observed classes/subgroups were compared longitudinally on LBP and mobility function outcomes using mixed models.
Results
Regarding LVMM, a model with 3 classes/subgroup fit best. Broadly speaking, subgroups were differentiated best by hip strength and symptom presence: subgroup 1 = strong and nonsymptomatic, subgroup 2 = weak and nonsymptomatic, and subgroup 3 = weak and symptomatic (WS). Regarding longitudinal mixed models, all subgroups improved in most outcomes over time. Specifically, over 12 months, the nonsymptomatic subgroups had lower LBP intensity and disability levels compared with the WS subgroup, whereas the strong and nonsymptomatic subgroup had better mobility function than the 2 “weak” subgroups.
Conclusion
These subgroup classifications may help in tailoring specific interventions in future trials. Special attention should be given to the WS subgroup given their consistently poor LBP and mobility function outcomes.
Impact
Among older adults with chronic low back pain, there are 3 hip subgroups: “strong and nonsymptomatic,” “weak and nonsymptomatic,” and “weak and symptomatic.” People in these subgroups demonstrate different outcomes and require different treatment; proper identification will result in tailored interventions designed to benefit individual patients. In particular, people in the WS subgroup deserve special attention, because their outcomes are consistently poorer than those in the other subgroups.
