Neurorehabilitation and neural repair最新文献

BackgroundThe extent to which the cholinergic system contributes to gait impairments in Parkinson's disease (PD) remains unclear. Electroencephalography (EEG) alpha reactivity, which refers to change in alpha power over occipital electrodes upon opening the eyes, has been suggested as a marker of cholinergic function. We compared alpha reactivity between people with PD and healthy individuals and explored its potential association with gait measures.MethodsEyes-closed and eyes-open resting-state EEG data were recorded from 20 people with idiopathic PD and 19 healthy individuals with a 64-channel EEG system. Alpha reactivity was calculated as the relative change in alpha power (8-13 Hz) over occipital electrodes from eyes-closed to eyes-open. Gait spatiotemporal measures were obtained with an electronic walkway.ResultsAlpha reactivity was reduced in people with PD compared to healthy individuals (U = 105, P = .017); the rank-biserial correlation of .447 indicated a moderate effect size. When controlling for global cognition (Mini Mental State Examination), the group difference in alpha reactivity was no longer significant. Alpha reactivity associated with measures of gait variability only (ρ = -.437 to -.532).ConclusionsResting-state alpha reactivity is reduced in PD, suggesting impaired cholinergic function. Reduced alpha reactivity was associated with greater gait variability, indicating a role of the cholinergic system in the mechanisms underlying gait variability. Therefore, the cholinergic system may represent a target for treatments aiming to reduce gait variability and alpha reactivity should be further explored as an endpoint for clinical trials.

ObjectivesAssessment of sensorimotor cortex and tracts degeneration using novel diffusion tensor imaging (DTI) templates in patients with chronic spinal cord injury (SCI) and its correlation with clinical and neurophysiological findings.MethodsSex and age-matched 29 patients with chronic SCI (paraplegic: p-SCI; tetraplegic: t-SCI) and 29 healthy controls underwent neurophysiological assessment including motor evoked potentials (MEP). DTI was performed on 3 T magnetic resonance imaging scanner and postprocessed using Human Motor Area and Sensorimotor Area Tract Templates. DTI parameters were compared using analysis of covariance with post hoc Scheffé and Bonferroni corrections. Spearman's rank test was used for correlations with P < .05 considered significant.ResultsCompared to controls, all SCI patients showed significantly lower fractional anisotropy (FA) in several tracts (primary motor [M1], somatosensory [S1], pre-supplementary motor area [preSMA], and dorsal premotor [PMd]) and cortices (M1, pre-SMA, and S1). There were no differences in DTI parameters between p-SCI and t-SCI or p-SCI and controls. Compared to controls, t-SCI showed significantly decreased FA within M1 and S1 tracts. In t-SCI higher motor scores were associated with higher FA from ventral premotor area (PMv) tracts and cortex; higher sensory scores were associated with higher FA from S1 tracts. Positive correlations were found between MEP amplitudes from rectus femoris muscles and FA for M1, PMd, PMv, pre-SMA, SMA tracts, and PMv cortex.ConclusionsDTI shows remote degeneration of sensorimotor cortex and supraspinal tracts in SCI correlating with several clinical motor and sensory scores, and MEP parameters. DTI metrics have the potential to become biomarkers of remote degeneration.

BackgroundSpoken language and environmental sounds hold rich and nuanced meaning for the listener, but depend on accurate hearing of the soundscape, including the timing, volume, and contrasts of its component pitches. Sensorineural hearing loss with aging degrades these properties, leading to progressive disability.ObjectivesThis case study and review describe my experience and behavioral accommodations to progressive bilateral hearing loss, limited compensation with hearing aids, and the stuttering evolution of gains after a unilateral cochlear implant (CI).ResultsDespite increasingly powerful hearing aids over 25 years, spoken phonemes and words became increasingly muffled, misheard, and often dissipated into ambient background noise. The cognitive effort to extract meaning and mask my disability grew exhausting. I gradually eliminated many of my usual family, medical career, and social roles. To try to recover some communication-dependent activities, I sought a bionic solution. A right-sided CI initially carried an ambiguous, fizzling code and unrecognizable synthetic voices. With 8 months of auditory rehabilitation, I better deciphered conversational speech and ambient sounds. By audiological testing, I improved from 10% hearing accuracy of single words to 65%, typical of post lingual adult users. Better hearing in ambient noise and for what had been excessively rapid speech evolved out to 18 months, allowing me to re-engage in many of my daily roles.ConclusionsHearing loss beyond the compensation of aids deeply challenges quality of life. Auditory rehabilitation after cochlear implantation engages neuroplasticity to re-establish functional communication.

Background: Physical, cognitive, and psychosocial impairments experienced by individuals post-stroke detrimentally impact health-related quality of life (HRQoL). Rehabilitation interventions targeting the recovery of motor function aim to improve community reintegration and HRQoL. Aerobic exercise has also been shown to have global effects in individuals post-stroke, positively affecting motor and mood-related outcomes.

Objective: To determine the effects of forced-rate aerobic exercise (FE) coupled with upper extremity repetitive task practice (RTP) on HRQoL and mood in individuals post-stroke.

Methods: A rater blinded randomized clinical trial was conducted. Individuals ≥6 months post-stroke received 90-minute sessions of FE+RTP or time-matched RTP alone, 3×/week for 8 weeks. The Stroke Impact Scale (SIS), Patient-Reported Outcomes Measurement Information System (PROMIS-29), and Centers For Epidemiology Studies-Depression Scale (CES-D) were administered at baseline, end of treatment (EOT), EOT+6 months, and EOT+12 months.

Results: Sixty participants enrolled in the study and 57 completed the self-reported questionnaires (FE + RTP, N = 29; RTP alone, N = 28). Both groups improved significantly at each time point in the following SIS domains: physical problems, feelings, activities of daily living, mobility, hand use, meaningful activities, and overall recovery; and in the participation domain of PROMIS-29. Depressive symptomology as measured by CES-D improved from baseline to EOT+6. There were no significant group differences in any of the outcomes.

Conclusions: Both interventions were comparably effective in improving HRQoL despite the FE+RTP group receiving only half the dose of RTP compared to the control group (RTP only). Improvements were maintained up to 1 year post-intervention.

BackgroundPhantom auditory percepts are especially prevalent in healthy persons with hearing loss. No first-person description of the not uncommon illusion called musical hallucinosis (MH) has been published in relation to possible neural mechanisms for its occurrence.ObjectivesThe author presents his personal experience following implantation of a unilateral cochlear neuroprosthesis to try to compensate for progressive sensorineural hearing loss.ResultsThe MH included abrupt onset of persistent, robust singing of the Star-Spangled Banner, then other familiar songs and nursery rhymes by a men's choir without accompanying instrumentals, followed months later by continuous nonsense lyrics sung to a simpler stereotyped tune. The onset was associated with deafness as a complication of electrode placement within the cochlea, the early sizzling, synthetic, monotonal auditory sounds heard using the cochlear implant, and a burst of cacophonous tinnitus following a higher volume adjustment to the device.ConclusionsSeveral physiological alterations, including deafferentation-induced spontaneous auditory pathway activity that triggers higher auditory cortical areas to place the ambiguous inputs within the individual's prior experience of sound patterns, may help explain the evolution of MH and its persistence as a type of maladaptive neuroplasticity.

Background. A single nucleotide polymorphism (SNP) in the catechol-o-methyltransferase (COMT) gene, Val158Met (rs4680), influences cognition in the general population. However, its role in stroke recovery is unclear. In this study, we evaluated the association of Val158Met SNP with stroke functional outcome and recovery. Methods. This is a retrospective study. The MGB Biobank was queried for 570 individuals with stroke and available genomics data. A subset of 164 was curated based on their admission to Spaulding Rehabilitation Hospital (SRH) for inpatient rehabilitation, meeting inclusion/exclusion criteria and receiving a rehabilitation program tailored to their individual needs and goals. Functional independent measures (FIM) were assessed upon admission to SRH and discharge. Multiple tests were performed to identify related clinic characteristics associated with functional outcome, recovery, and independence dichotomization. Logistic and linear regression models adjusted for covariate variables were used to evaluate the association between COMT Val58Met and functional outcome and recovery. Results. Genotype analysis confirmed that COMT Met/Met frequency was higher compared to Val allele frequency in high cognitive functional outcome. Furthermore, after adjusting for covariate variables, COMT Met/Met led to positive cognitive outcome (P = 0.029; OR = 2.43 [0.19-4.56)] in comprehension (P = 0.013, OR = 0.62 [0.15-1.08]) and expression (P = 0.007, OR = 0.74 [0.19-1.25]). In independence dichotomization analysis, high cognitive outcomes (P = 0.04, OR = 0.81 [1.04-4.82]) were found in the sub-domains of comprehension (P = 0.002, OR = 1.21 [1.56-7.17]), expression (P = 0.03, OR = 0.83 [1.08-4.83]), problem solving (P = 0.02, OR = 0.88 [1.15-5.06]), and memory (P = 0.039, OR = 0.78 [1.04-4.58]). Conclusion. Stroke patients with COMT Met/Met were associated with improved cognition, comprehension, and expression functional outcomes..

Background. Closed-loop rhythmic auditory stimulation (RAS) systems show promise for improving gait quality in people with Parkinson disease (PD). Objective: To examine auditory-motor entrainment and spatiotemporal gait responses to system-controlled rhythm tempo increase before and after a community-based RAS walking intervention. Methods. Thirteen persons with PD used an autonomous closed-loop RAS system during 30 walking sessions. Baseline (BL) and post-intervention (POST) gait responses to tempo increase were assessed as participants walked with the system in a clinic hallway. Rhythm tempo, entrainment, cadence, stride length, gait speed, and stride time variability (STV) were measured during the first minute (tempo at preferred walking cadence, prior to increase) and fifth minute (tempo above preferred cadence, following increase) of each assessment. Within- and between-assessment responses of entrainment and spatiotemporal variables to tempo increase were evaluated. Results. During each assessment, participants entrained to rhythmic cues while significantly increasing their cadence and stride length in response to tempo increase. Gait speed increased significantly only during the POST assessment. Nearly 70% of participants had significantly lower mean STV at the POST assessment compared to BL, indicating increased gait rhythmicity. The between-assessment decrease in STV was associated with increased stride length. Conclusions. Study findings supported the potential of an autonomous closed-loop RAS system to induce entrainment and meaningful gait responses to system-controlled tempo increase in persons with PD. The system appeared to promote implicit motor learning processes during use. Associated post-intervention improvements in rhythmicity and stride length in a subset of participants were suggestive of fall prevention effects.Trial registration: Prospectively registered at ClinicalTrials.gov (NCT05421624).

Background. Conventional physical therapy following neurological injury is an arduous task met with minimal returns and quickly plateauing recovery. Unconventional therapies, such as robotic assisted gait training (RAGT) have not produced the robust clinical gains that we all had hoped. Rodent RAGT is a nascent field, but it works on the same principles as the clinical counterpart. Objective. We have previously investigated the ability of RAGT to enhance the recovery of rats following a cervical spinal cord injury and found that training in a resistive field is detrimental, and training in a negative viscosity field is better than actively guiding the limbs through a healthy stepping pattern. Unfortunately, none of these treatments are particularly good at restoring unassisted overground locomotion. Previously we grouped animals based on the RAGT treatment they received. Upon further reflection, these groups are not based on what the animals actually experienced, but how the robot was programmed. Methods. In the work presented here we regrouped and reanalyzed our existing data bi-directionally (does level of overground recovery predict RAGT force profile experienced? does force profile predict recovery?). Results. This method allowed us to uncover a training force profile that optimized overground recovery, specifically, low overall forces (<±6 N), positive Fy and negative Fx during swing, and minimal forces during stance (<±2 N). Conclusions. This work provides new insights into the importance of the specific forces used in rehabilitation, a major shift in current clinical RAGT techniques, and could lead to improvements in patients' lives.

BackgroundCompromised dual-task walking ability reduces functional independence in community-dwelling individuals after stroke. Objective. To examine the influence of mobility task and cognitive task type and complexity, and their interaction on dual-task level-ground walking and obstacle-crossing after stroke.MethodsNinety-three individuals with chronic stroke (mean [SD] age = 62.4 [6.7] years, stroke duration = 67.7 [53.5] months) participated in this observational study with repeated measures. For each dual-task testing condition, a mobility task (level-ground walking or obstacle-crossing) was performed concurrently with 1 of 5 cognitive tasks (serial-subtractions, category naming, clock test, auditory discrimination, and shopping-list recall). Each cognitive task involved low and high complexity levels, yielding 20 dual-task conditions in total. Dual-task effect (DTE = [single-task - dual-task]×100/single-task) on walking distance (mobility-DTE) and number of correct responses (cognitive-DTE) were calculated for each dual-task condition.ResultsMedium to large interaction effects were observed between cognitive task type and complexity on cognitive (F = 12.0-15.8, P < .001, ηp² = 0.12-0.15) and mobility performance (F = 3.2-5.5, P < .05, ηp² = 0.03-0.06) during dual-task level-ground walking and obstacle-crossing. Among the cognitive tasks, serial-subtraction had the greatest interference effect on both cognitive (Mean DTE = -9.2 to -21.5%) and mobility performance (Mean DTE = -18.7 to -19.1%). Overall, "mobility interference" (decrement in walking distance without a decrement in cognitive performance) was the most common dual-task effect pattern observed.ConclusionThe type and complexity level of the mobility and cognitive tasks interact to influence the degree and pattern of dual-task effects, with the serial-subtraction task inducing the greatest effect. Standardized assessments involving distinct cognitive domains are necessary for profiling dual-task interference during walking among individuals with chronic stroke.

BackgroundVariability in movement is critical for performance under dynamic conditions. Stroke causes focal injury to the motor system, disrupts voluntary motor control, and leads to less smooth and more variable upper extremity movements. Few studies have characterized trial-by-trial variation in upper extremity movement smoothness and its clinical and neuroanatomic correlates in the first week post-stroke.ObjectiveTo evaluate trial-by-trial variation in upper extremity movement smoothness during planar reaching and relate it to clinical outcomes and neuroanatomical injury after acute stroke.MethodsTwenty-two patients (4.4 ± 1.7 days post-stroke) and 22 able-bodied adults completed a planar center-out reaching task. Smoothness was quantified with spectral arc length (SPARC). Median and interquartile range (IQR, a quantification of trial-by-trial variation) of SPARC values were assessed. Patients completed a clinical assessment battery acutely and at 90 days post-stroke. MRI-derived stroke lesions were analyzed to estimate basal ganglia, motor cortex, and corticospinal tract injury. Intraclass correlation, Spearman's correlation, and multivariate regression evaluated trial-by-trial variation and its relation to clinical assessments, outcomes, and neuroanatomical injury.ResultsPost-stroke reaching was less smooth and more variable (larger IQR) compared to able-bodied adults. Variability in post-stroke smoothness was primarily driven by within-subject, trial-by-trial variation. More variable smoothness, even after controlling for median smoothness, related to worse performance on clinical assessments and 90-day outcomes. More variable smoothness related to greater corticospinal tract injury (ρ = 0.537, P = .011), but not to basal ganglia or motor cortex injury.ConclusionTrial-by-trial variation of movement is valuable for understanding sensorimotor control post-stroke and has implications for targeted neurorehabilitation.