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1.
Neuroimage ; 263: 119644, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36170952

RESUMEN

White matter (WM) neuroplasticity in the human brain has been tracked non-invasively using advanced magnetic resonance imaging techniques, with increasing evidence for improved axonal transmission efficiency as a central mechanism. The current study is the culmination of a series of studies, which characterized the structure-function relationship of WM transmission efficiency in the cortico-spinal tract (CST) during motor learning. Here, we test the hypothesis that increased transmission efficiency is linked directly to increased myelination using myelin water imaging (MWI). MWI was used to evaluate neuroplasticity-related improvements in the CST. The MWI findings were then compared to diffusion tensor imaging (DTI) results, with the secondary hypothesis that radial diffusivity (RD) would have a stronger relationship than axial diffusivity (AD) if the changes were due to increased myelination. Both MWI and RD data showed the predicted pattern of significant results, strongly supporting that increased myelination plays a central role in WM neuroplasticity.


Asunto(s)
Sustancia Blanca , Humanos , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patología , Imagen de Difusión Tensora/métodos , Encéfalo/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética , Imagen por Resonancia Magnética , Agua
2.
J Neurol Phys Ther ; 44(2): 164-172, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32168159

RESUMEN

BACKGROUND AND PURPOSE: Therapeutic exercise improves balance and walking ability in individuals after stroke. The extent to which motor planning improves with therapeutic exercise is unknown. This case series examined how outpatient physical therapy affects motor planning and motor performance for stepping. CASE DESCRIPTION: Individuals poststroke performed self-initiated stepping before (baseline), after (postintervention), and 1 month after (retention) intervention. Amplitude and duration of the movement-related cortical potential (MRCP) was measured using an electroencephalograph from the Cz electrode. Electromyography (EMG) of biceps femoris (BF) was collected. Additionally, clinical measures of motor impairment and function were evaluated at all 3 time points by a blinded assessor. INTERVENTION: Two types of outpatient physical therapy were performed for 6 weeks: CONVENTIONAL (n = 3) and FAST (n = 4, Fast muscle Activation and Stepping Training). OUTCOMES: All 7 participants reduced MRCP duration, irrespective of the type of physical therapy. The MRCP amplitude and BF EMG onset changes were more variable. Clinical outcomes improved or were maintained for all participants. The extent of motor impairment was associated with MRCP amplitude. DISCUSSION: Changes in MRCP duration suggest that outpatient physical therapy may promote neuroplasticity of motor planning of stepping movements after stroke; however, a larger sample is needed to determine whether this finding is valid.This case series suggests motor planning for initiating stepping may improve after 6 weeks of outpatient physical therapy for persons with stroke.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A307).


Asunto(s)
Corteza Cerebral/fisiopatología , Terapia por Ejercicio , Plasticidad Neuronal/fisiología , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular/fisiopatología , Caminata/fisiología , Anciano , Anciano de 80 o más Años , Electroencefalografía , Electromiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología
3.
J Neuroeng Rehabil ; 17(1): 158, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-33261623

RESUMEN

BACKGROUND: In a recent high-profile case study, we used functional magnetic resonance imaging (fMRI) to monitor improvements in motor function related to neuroplasticity following rehabilitation for severe traumatic brain injury (TBI). The findings demonstrated that motor function improvements can occur years beyond current established limits. The current study extends the functional imaging investigation to characterize neuromodulation effects on neuroplasticity to further push the limits. METHODS: Canadian Soldier Captain (retired) Trevor Greene (TG) survived a severe open-TBI when attacked with an axe during a 2006 combat tour in Afghanistan. TG has since continued intensive daily rehabilitation to recover motor function, experiencing an extended plateau using conventional physical therapy. To overcome this plateau, we paired translingual neurostimulation (TLNS) with the continuing rehabilitation program. RESULTS: Combining TLNS with rehabilitation resulted in demonstrable clinical improvements along with corresponding changes in movement evoked electro-encephalography (EEG) activity. High-density magneto-encephalography (MEG) characterized cortical activation changes in corresponding beta frequency range (27 Hz). MEG activation changes corresponded with reduced interhemispheric inhibition in the post-central gyri regions together with increased right superior/middle frontal activation suggesting large scale network level changes. CONCLUSIONS: The findings provide valuable insight into the potential importance of non-invasive neuromodulation to enhance neuroplasticity mechanisms for recovery beyond the perceived limits of rehabilitation.


Asunto(s)
Lesiones Traumáticas del Encéfalo/rehabilitación , Encéfalo/fisiopatología , Terapia por Estimulación Eléctrica/métodos , Plasticidad Neuronal/fisiología , Recuperación de la Función/fisiología , Adulto , Canadá , Terapia por Estimulación Eléctrica/instrumentación , Electroencefalografía , Humanos , Imagen por Resonancia Magnética , Magnetoencefalografía/métodos , Masculino , Modalidades de Fisioterapia
4.
Mov Disord ; 34(12): 1891-1900, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31584222

RESUMEN

BACKGROUND: The objective of this study was to examine the effects of aerobic exercise on evoked dopamine release and activity of the ventral striatum using positron emission tomography and functional magnetic resonance imaging in Parkinson's disease (PD). METHODS: Thirty-five participants were randomly allocated to a 36-session aerobic exercise or control intervention. Each participant underwent an functional magnetic resonance imaging scan while playing a reward task before and after the intervention to determine the effect of exercise on the activity of the ventral striatum in anticipation of reward. A subset of participants (n = 25) completed [11 C] raclopride positron emission tomography scans to determine the effect of aerobic exercise on repetitive transcranial magnetic stimulation-evoked release of endogenous dopamine in the dorsal striatum. All participants completed motor (MDS-UPDRS part III, finger tapping, Timed-up-and-go) and nonmotor assessments (Starkstein Apathy Scale, Beck Depression Inventory, reaction time, Positive and Negative Affect Schedule, Trail Making Test [A and B], and Montreal Cognitive Assessment) before and after the interventions. RESULTS: The aerobic group exhibited increased activity in the ventral striatum during functional magnetic resonance imaging in anticipation of 75% probability of reward (P = 0.01). The aerobic group also demonstrated increased repetitive transcranial magnetic stimulation-evoked dopamine release in the caudate nucleus (P = 0.04) and increased baseline nondisplaceable binding potential in the posterior putamen of the less affected repetitive transcranial magnetic stimulation-stimulated hemisphere measured by position emission tomography (P = 0.03). CONCLUSIONS: Aerobic exercise alters the responsivity of the ventral striatum, likely related to changes to the mesolimbic dopaminergic pathway, and increases evoked dopamine release in the caudate nucleus. This suggests that the therapeutic benefits of exercise are in part related to corticostriatal plasticity and enhanced dopamine release. © 2019 International Parkinson and Movement Disorder Society.


Asunto(s)
Núcleo Caudado/metabolismo , Dopamina/metabolismo , Ejercicio Físico/fisiología , Enfermedad de Parkinson/metabolismo , Estriado Ventral/metabolismo , Anciano , Anciano de 80 o más Años , Núcleo Caudado/diagnóstico por imagen , Terapia por Ejercicio , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/diagnóstico por imagen , Enfermedad de Parkinson/psicología , Tomografía de Emisión de Positrones , Estudios Prospectivos , Tomografía Computarizada por Rayos X , Estimulación Magnética Transcraneal , Estriado Ventral/diagnóstico por imagen
5.
J Neuroeng Rehabil ; 16(1): 60, 2019 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-31133021

RESUMEN

BACKGROUND: Despite growing evidence of a critical link between neuromodulation technologies and neuroplastic recovery, the underlying mechanisms of these technologies remain elusive. OBJECTIVE: To investigate physiological evidence of central nervous system (CNS) changes in humans during translingual neurostimulation (TLNS). METHODS: We used high-density electroencephalography (EEG) to measure changes in resting brain activity before, during, and after high frequency (HF) and low frequency (LF) TLNS. RESULTS: Wavelet power analysis around Cz and microstate analysis revealed significant changes after 20 min of stimulation compared to baseline. A secondary effect of exposure order was also identified, indicating a differential neuromodulatory influence of HF TLNS relative to LF TLNS on alpha and theta signal power. CONCLUSIONS: These results further our understanding of the effects of TLNS on underlying resting brain activity, which in the long-term may contribute to the critical link between clinical effect and changes in brain activity.


Asunto(s)
Encéfalo/fisiología , Estimulación Eléctrica/métodos , Lengua , Adulto , Electroencefalografía , Femenino , Humanos , Masculino , Plasticidad Neuronal/fisiología , Descanso/fisiología
6.
Exp Brain Res ; 235(1): 293-304, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27709269

RESUMEN

While concurrent augmented visual feedback of the center of pressure (COP) or center of gravity (COG) can improve quiet standing balance control, it is not known whether such feedback improves reactive balance control. Additionally, it is not known whether feedback of the COP or COG is superior. This study aimed to determine whether (1) concurrent augmented feedback can improve reactive balance control, and (2) feedback of the COP or COG is more effective. Forty-eight healthy older adults (60-75 years old) were randomly allocated to one of three groups: feedback of the COP, feedback of the COG, or no feedback. The task was to maintain standing while experiencing 30 s of continuous pseudo-random perturbations delivered by a moving platform. Participants completed 25 trials with or without feedback (acquisition), immediately followed by 5 trials without feedback (immediate transfer); 5 trials without feedback were completed after a 24-h delay (delayed transfer). The root mean square error (RMSE) of COP-COG, electrodermal level, and co-contraction index were compared between the groups and over time. All three groups reduced RMSE and co-contraction index from the start of the acquisition to the transfer tests, and there were no significant between-group differences in RMSE or co-contraction on the transfer tests. Therefore, all three groups learned the task equally well, and improved balance was achieved with practice via a more efficient control strategy. The two feedback groups reduced electrodermal level with practice, but the no-feedback group did not, suggesting that feedback may help to reduce anxiety.


Asunto(s)
Envejecimiento/fisiología , Retroalimentación Sensorial/fisiología , Equilibrio Postural/fisiología , Transferencia de Experiencia en Psicología/fisiología , Anciano , Análisis de Varianza , Electromiografía , Femenino , Gravitación , Humanos , Masculino , Persona de Mediana Edad , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Presión , Factores de Tiempo
7.
Neural Plast ; 2016: 7526135, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27293906

RESUMEN

Experience-dependent structural changes are widely evident in gray matter. Using diffusion weighted imaging (DWI), the neuroplastic effect of motor training on white matter in the brain has been demonstrated. However, in humans it is not known whether specific features of white matter relate to motor skill acquisition or if these structural changes are associated to functional network connectivity. Myelin can be objectively quantified in vivo and used to index specific experience-dependent change. In the current study, seventeen healthy young adults completed ten sessions of visuomotor skill training (10,000 total movements) using the right arm. Multicomponent relaxation imaging was performed before and after training. Significant increases in myelin water fraction, a quantitative measure of myelin, were observed in task dependent brain regions (left intraparietal sulcus [IPS] and left parieto-occipital sulcus). In addition, the rate of motor skill acquisition and overall change in myelin water fraction in the left IPS were negatively related, suggesting that a slower rate of learning resulted in greater neuroplastic change. This study provides the first evidence for experience-dependent changes in myelin that are associated with changes in skilled movements in healthy young adults.


Asunto(s)
Aprendizaje/fisiología , Destreza Motora/fisiología , Vaina de Mielina/fisiología , Plasticidad Neuronal/fisiología , Sustancia Blanca/fisiología , Adulto , Imagen de Difusión por Resonancia Magnética/métodos , Femenino , Humanos , Masculino , Desempeño Psicomotor/fisiología , Adulto Joven
8.
J Neurol Phys Ther ; 39(1): 43-51, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25522236

RESUMEN

A wide array of neuroimaging technologies are now available that offer unprecedented opportunities to study the brain in health and disease. Each technology has associated strengths and weaknesses that need to be considered to maximize their utility, especially when used in combination. One imaging technology, electroencephalography (EEG), has been in use for more than 80 years, but as a result of recent technologic advancements EEG has received renewed interest as an inexpensive, noninvasive and versatile technique to evaluate neural activity in the brain. In part, this is due to new opportunities to combine EEG not only with other imaging modalities, but also with neurostimulation and robotics technologies. When used in combination, noninvasive brain stimulation and EEG can be used to study cause-and-effect relationships between interconnected brain regions providing new avenues to study brain function. Although many of these approaches are still in the developmental phase, there is substantial promise in their ability to deepen our understanding of brain function. The ability to capture the causal relationships between brain function and behavior in individuals with neurologic disorders or injury has important clinical implications for the development of novel biomarkers of recovery and response to therapeutic interventions. The goals of this paper are to provide an overview of the fundamental principles of EEG; discuss past, present, and future applications of EEG in the clinical management of stroke; and introduce the technique of combining EEG with a form of noninvasive brain stimulation, transcranial magnetic stimulation, as a powerful synergistic research paradigm to characterize brain function in both health and disease.Video Abstract available (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A87) for more insights from the authors.


Asunto(s)
Encéfalo/fisiopatología , Electroencefalografía , Accidente Cerebrovascular/fisiopatología , Humanos
9.
Rev Neurosci ; 25(5): 687-97, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24854534

RESUMEN

The ability to maintain balance is critical for daily activities such as walking and fall avoidance. The contemporary models of postural control emphasize the central and somatic interactions engaged in maintaining balance; however, there is emerging evidence that the autonomic nervous system (ANS) - the sympathetic division, in particular - routinely participates in postural control. The purpose of this paper is to review the evidence demonstrating the autonomic interactions in postural control. These interactions are presented in two broad categories: those that conceptualize the maintenance of postural equilibrium as a component of bodily homeostasis and those that illustrate how changes in affective states link cognitive perceptions and physiological responses (in this case, balance). The shared commonalities between postural and autonomic pathways are presented, pointing to the areas of overlap and the potential sources of the interaction. Although the specific function of autonomic engagement in postural control remains unknown, the potential roles are explored and highlight the directions for continued study.


Asunto(s)
Sistema Nervioso Autónomo/fisiología , Equilibrio Postural , Sistema Nervioso Central/fisiología , Humanos
10.
Front Hum Neurosci ; 18: 1358551, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38628971

RESUMEN

Objective, rapid evaluation of cognitive function is critical for identifying situational impairment due to sleep deprivation. The present study used brain vital sign monitoring to evaluate acute changes in cognitive function for healthy adults. Thirty (30) participants were scanned using portable electroencephalography before and after either a night of regular sleep or a night of total sleep deprivation. Brain vital signs were extracted from three established event-related potential components: (1) the N100 (Auditory sensation); (2) the P300 (Basic attention); and (3) the N400 (Cognitive processing) for all time points. As predicted, the P300 amplitude was significantly reduced in the sleep deprivation group. The findings indicate that it is possible to detect situational cognitive impairment due to sleep deprivation using objective, rapid brain vital sign monitoring.

11.
Exp Brain Res ; 230(3): 261-70, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23897132

RESUMEN

Evoked autonomic nervous system (ANS) activity may be an important modulator of rapid reactions, generated in the face of urgency and may serve to augment the parallel somatosensory processing to adjust speed of processing. The primary objective of the current study was to temporally pair auditory stimuli with whole body perturbations to determine if conditioning could 'prime' the central nervous system (CNS) to respond faster and with greater ANS reactivity to the auditory stimulus alone. Healthy young participants (n = 19) were seated in a custom chair, which tilted backwards upon the release of an electromagnet and were instructed to reach to grasp a handle located in front of their arm as fast as possible following an auditory cue. Three conditions were completed in the following order: (1) baseline-auditory cue alone (5 trials); (2) paired-auditory cue, followed by a chair tilt 110 ms later (20 trials); and (3) post-pairing-auditory cue alone (5 trials). Participants were not informed of the switch from paired to auditory-only stimuli in the first trial of the post-pairing task condition. Reaction time was measured using electromyography, and autonomic nervous system activity was monitored via the electrodermal response (EDR). The first trial post-pairing had significantly faster reaction time (Δ = 21 ms) and significantly greater EDR amplitude compared to the last trial prior to pairing (baseline). The amplitude of contraction and overall time to handle contact were not significantly different between the first trial post-pairing and the last trial prior to pairing. This study demonstrates that the CNS can be 'primed' to generate rapid reactions and an elevated autonomic response in the absence of whole body instability. This indicates that afferent volume generated following whole body instability is not the only determinant of rapid reactions and emphasizes the importance of physiologic measures of autonomic activity with respect to stimulus-evoked reaction time.


Asunto(s)
Encéfalo/fisiología , Extremidad Superior/fisiología , Estimulación Acústica , Adulto , Sistema Nervioso Autónomo/fisiología , Electromiografía , Potenciales Evocados Auditivos/fisiología , Femenino , Respuesta Galvánica de la Piel , Fuerza de la Mano/fisiología , Humanos , Masculino , Movimiento/fisiología , Músculo Esquelético/fisiología , Estimulación Física , Tiempo de Reacción/fisiología , Procesamiento de Señales Asistido por Computador , Adulto Joven
13.
Arch Phys Med Rehabil ; 93(7): 1179-84, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22480548

RESUMEN

OBJECTIVE: To investigate the determinants of limb preference for initiating compensatory stepping poststroke. DESIGN: Retrospective chart review. SETTING: Inpatient rehabilitation. PARTICIPANTS: Convenience sample of individuals admitted to inpatient rehabilitation with poststroke hemiparesis. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Compensatory stepping responses were evoked using a lean-and-release postural perturbation. The limb used to initiate compensatory stepping was determined. The relationships between stepping with the paretic limb and premorbid limb dominance, weight bearing on the paretic limb in quiet standing, ability to bear weight on the paretic limb, preperturbation weight bearing on the paretic limb, and lower-limb motor recovery scores were determined. RESULTS: The majority (59.1%) of responses were steps initiated with the nonparetic limb. Increased lower-limb motor recovery scores and preperturbation weight bearing on the nonparetic limb were significantly related to increased frequency of stepping with the paretic limb. When the preferred limb was physically blocked, an inappropriate response was initiated in 21% of trials (ie, nonstep responses or an attempt to step with the blocked limb). CONCLUSIONS: This study reveals the challenges that individuals with poststroke hemiparesis face when executing compensatory stepping responses to prevent a fall after a postural perturbation. The inability or challenges to executing a compensatory step with the paretic limb may increase the risk for falls poststroke.


Asunto(s)
Trastornos Neurológicos de la Marcha/rehabilitación , Paresia/rehabilitación , Equilibrio Postural/fisiología , Trastornos de la Sensación/rehabilitación , Rehabilitación de Accidente Cerebrovascular , Accidentes por Caídas/prevención & control , Adaptación Fisiológica , Estudios de Cohortes , Terapia por Ejercicio/métodos , Femenino , Estudios de Seguimiento , Trastornos Neurológicos de la Marcha/diagnóstico , Humanos , Pacientes Internos/estadística & datos numéricos , Extremidad Inferior/fisiopatología , Masculino , Paresia/etiología , Paresia/fisiopatología , Prioridad del Paciente , Tiempo de Reacción , Centros de Rehabilitación , Estudios Retrospectivos , Trastornos de la Sensación/etiología , Trastornos de la Sensación/fisiopatología , Índice de Severidad de la Enfermedad , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico , Análisis y Desempeño de Tareas , Resultado del Tratamiento , Caminata/fisiología
14.
Neurorehabil Neural Repair ; 36(6): 381-389, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35533214

RESUMEN

BACKGROUND: Myelin asymmetry ratios (MARs) relate and contribute to motor impairment and function after stroke. Physical activity (PA) may induce myelin plasticity, potentially mitigating hemispheric myelin asymmetries that can occur after a stroke. OBJECTIVE: The aim of this study was to determine whether individuals with higher levels of PA showed lower MAR compared to individuals with lower levels of PA. METHODS: Myelin water fraction was obtained from 5 bilateral motor regions in 22 individuals with chronic stroke and 26 healthy older adults. Activity levels were quantified with wrist accelerometers worn for a period of 72 hours (3 days). Higher and lower PA levels were defined by a cluster analysis within each group. RESULTS: MAR was similar regardless of PA level within the older adult group. Compared to the higher PA stroke group, lower PA stroke participants displayed greater MAR. There was no difference in MAR between the stroke and older adult higher PA groups. Within the lower PA groups, individuals with stroke showed greater MAR compared to the older adults. Arm impairment, lesion volume, age, time since stroke, and preferential arm use were not different between the PA stroke groups, suggesting that motor impairment severity and extent of brain damage did not drive differences in PA. CONCLUSION: Individuals who have had a stroke and are also physically active display lower MAR (i.e., similar myelin in both hemispheres) in motor regions. High levels of PA may be neuroprotective and mitigate myelin asymmetries once a neurological insult, such as a stroke, occurs. Alternately, it is possible that promoting high levels of PA after a stroke may reduce myelin asymmetries.


Asunto(s)
Vaina de Mielina , Accidente Cerebrovascular , Anciano , Ejercicio Físico , Humanos , Extremidad Superior , Muñeca
15.
Neurorehabil Neural Repair ; 35(6): 513-524, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33825574

RESUMEN

OBJECTIVE: Activity patterns across brain regions that can be characterized at rest (ie, resting-state functional connectivity [rsFC]) are disrupted after stroke and linked to impairments in motor function. While changes in rsFC are associated with motor recovery, it is not clear how rsFC is modulated by skilled motor practice used to promote recovery. The current study examined how rsFC is modulated by skilled motor practice after stroke and how changes in rsFC are linked to motor learning. METHODS: Two groups of participants (individuals with stroke and age-matched controls) engaged in 4 weeks of skilled motor practice of a complex, gamified reaching task. Clinical assessments of motor function and impairment, and brain activity (via functional magnetic resonance imaging) were obtained before and after training. RESULTS: While no differences in rsFC were observed in the control group, increased connectivity was observed in the sensorimotor network, linked to learning in the stroke group. Relative to healthy controls, a decrease in network efficiency was observed in the stroke group following training. CONCLUSIONS: Findings indicate that rsFC patterns related to learning observed after stroke reflect a shift toward a compensatory network configuration characterized by decreased network efficiency.


Asunto(s)
Corteza Cerebral/fisiopatología , Conectoma , Destreza Motora/fisiología , Red Nerviosa/fisiopatología , Práctica Psicológica , Accidente Cerebrovascular/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Cerebelo/diagnóstico por imagen , Cerebelo/fisiopatología , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Corteza Sensoriomotora/diagnóstico por imagen , Corteza Sensoriomotora/fisiopatología , Accidente Cerebrovascular/diagnóstico por imagen
16.
Front Neurosci ; 15: 670563, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34434084

RESUMEN

Background: Prior concussion studies have shown that objective neurophysiological measures are sensitive to detecting concussive and subconcussive impairments in youth ice-hockey. These studies monitored brain vital signs at rink-side using a within-subjects design to demonstrate significant changes from pre-season baseline scans. However, practical clinical implementation must overcome inherent challenges related to any dependence on a baseline. This requires establishing the start of normative reference data sets. Methods: The current study collected specific reference data for N = 58 elite, youth, male ice-hockey players and compared these with a general reference dataset from N = 135 of males and females across the lifespan. The elite hockey players were recruited to a select training camp through CAA Hockey, a management agency for players drafted to leagues such as the National Hockey League (NHL). The statistical analysis included a test-retest comparison to establish reliability, and a multivariate analysis of covariance to evaluate differences in brain vital signs between groups with age as a covariate. Findings: Test-retest assessments for brain vital signs evoked potentials showed moderate-to-good reliability (Cronbach's Alpha > 0.7, Intraclass correlation coefficient > 0.5) in five out of six measures. The multivariate analysis of covariance showed no overall effect for group (p = 0.105), and a significant effect of age as a covariate was observed (p < 0.001). Adjusting for the effect of age, a significant difference was observed in the measure of N100 latency (p = 0.022) between elite hockey players and the heterogeneous control group. Interpretation: The findings support the concept that normative physiological data can be used in brain vital signs evaluation in athletes, and should additionally be stratified for age, skill level, and experience. These can be combined with general norms and/or individual baseline assessments where appropriate and/or possible. The current results allow for brain vital sign evaluation independent of baseline assessment, therefore enabling objective neurophysiological evaluation of concussion management and cognitive performance optimization in ice-hockey.

17.
Exp Neurol ; 346: 113853, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34464653

RESUMEN

Experience-dependent white matter plasticity offers new potential for rehabilitation-induced recovery after neurotrauma. This first-in-human translational experiment combined myelin water imaging in humans and genetic fate-mapping of oligodendrocyte lineage cells in mice to investigate whether downhill locomotor rehabilitation that emphasizes eccentric muscle actions promotes white matter plasticity and recovery in chronic, incomplete spinal cord injury (SCI). In humans, of 20 individuals with SCI that enrolled, four passed the imaging screen and had myelin water imaging before and after a 12-week (3 times/week) downhill locomotor treadmill training program (SCI + DH). One individual was excluded for imaging artifacts. Uninjured control participants (n = 7) had two myelin water imaging sessions within the same day. Changes in myelin water fraction (MWF), a histopathologically-validated myelin biomarker, were analyzed in a priori motor learning and non-motor learning brain regions and the cervical spinal cord using statistical approaches appropriate for small sample sizes. PDGFRα-CreERT2:mT/mG mice, that express green fluorescent protein on oligodendrocyte precursor cells and subsequent newly-differentiated oligodendrocytes upon tamoxifen-induced recombination, were either naive (n = 6) or received a moderate (75 kilodyne), contusive SCI at T9 and were randomized to downhill training (n = 6) or unexercised groups (n = 6). We initiated recombination 29 days post-injury, seven days prior to downhill training. Mice underwent two weeks of daily downhill training on the same 10% decline grade used in humans. Between-group comparison of functional (motor and sensory) and histological (oligodendrogenesis, oligodendroglial/axon interaction, paranodal structure) outcomes occurred post-training. In humans with SCI, downhill training increased MWF in brain motor learning regions (postcentral, precuneus) and mixed motor and sensory tracts of the ventral cervical spinal cord compared to control participants (P < 0.05). In mice with thoracic SCI, downhill training induced oligodendrogenesis in cervical dorsal and lateral white matter, increased axon-oligodendroglial interactions, and normalized paranodal structure in dorsal column sensory tracts (P < 0.05). Downhill training improved sensorimotor recovery in mice by normalizing hip and knee motor control and reducing hyperalgesia, both of which were associated with new oligodendrocytes in the cervical dorsal columns (P < 0.05). Our findings indicate that eccentric-focused, downhill rehabilitation promotes white matter plasticity and improved function in chronic SCI, likely via oligodendrogenesis in nervous system regions activated by the training paradigm. Together, these data reveal an exciting role for eccentric training in white matter plasticity and sensorimotor recovery after SCI.


Asunto(s)
Rehabilitación Neurológica/métodos , Plasticidad Neuronal/fisiología , Desempeño Psicomotor/fisiología , Recuperación de la Función/fisiología , Traumatismos de la Médula Espinal/rehabilitación , Sustancia Blanca/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Enfermedad Crónica , Prueba de Esfuerzo/métodos , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad , Traumatismos de la Médula Espinal/diagnóstico por imagen , Traumatismos de la Médula Espinal/fisiopatología , Sustancia Blanca/diagnóstico por imagen , Adulto Joven
18.
Front Hum Neurosci ; 14: 347, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33132868

RESUMEN

Using a longitudinal case study design, we have tracked the recovery of motor function following severe traumatic brain injury (TBI) through a multimodal neuroimaging approach. In 2006, Canadian Soldier Captain (retired) Trevor Greene (TG) was attacked with an axe to the head while on tour in Afghanistan. TG continues intensive daily rehabilitation, which recently included the integration of physical therapy (PT) with neuromodulation using translingual neurostimulation (TLNS) to facilitate neuroplasticity. Recent findings with PT + TLNS demonstrated that recovery of motor function occurred beyond conventional time limits, currently extending past 14-years post-injury. To investigate whether PT + TLNS similarly resulted in associated cognitive function improvements, we examined event-related potentials (ERPs) with the brain vital signs framework. In parallel with motor function improvements, brain vital signs detected significant increases in basic attention (as measured by P300 response amplitude) and cognitive processing (as measured by contextual N400 response amplitude). These objective cognitive improvements corresponded with TG's self-reported improvements, including a noteworthy and consistent reduction in ongoing symptoms of post-traumatic stress disorder (PTSD). The findings provide valuable insight into the potential importance of non-invasive neuromodulation in cognitive rehabilitation, in addition to initial indications for physical rehabilitation.

19.
Front Hum Neurosci ; 14: 358, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33117138

RESUMEN

Background: Neuromodulation through translingual neurostimulation (TLNS) has been shown to initiate long-lasting processes of neuronal reorganization with a variety of outcomes (i.e., neuroplasticity). Non-invasive TLNS is increasingly accessible through the Portable Neuromodulation Stimulator (PoNS®), a medical device that delivers electrical stimulation to the tongue to activate the trigeminal (V) and facial (VII) cranial nerves. Anecdotal reports from previous clinical studies have suggested incidental improvements in cognitive function. To objectively explore this observation, we examined TLNS-related effects on the semantic N400 brain vital sign cognitive response during cognitive skills training in healthy individuals. Methods: Thirty-seven healthy volunteers were randomized to receive simultaneous TLNS (treatment) or no TLNS (control) while undergoing cognitive skills training. Cognitive training was conducted for two 20-min sessions (morning and afternoon/evening) over 3 consecutive days. Brain vital signs were evaluated at baseline, Day 1, and Day 3. Analyses focused on cognitive processing as measured by N400 changes in amplitude and latency. Results: Over the 3-day course of cognitive training, the N400 amplitude decreased significantly in the control group due to habituation (p = 0.028). In contrast, there was no significant change in the TLNS treatment group. Conclusion: TLNS led to a sustained N400 response during cognitive skills training, as measured by the brain's vital signs framework. The study findings suggest differential learning effects due to neuromodulation, consistent with increased attention and cognitive vigilance.

20.
Clin Neurophysiol ; 129(4): 787-796, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29453170

RESUMEN

OBJECTIVE: This study examined motor planning for stepping when the paretic leg was either stepping or standing (to step with the non-paretic leg), to understand whether difficulty with balance and walking post-stroke could be attributed to poor motor planning. METHODS: Individuals with stroke performed self-initiated stepping. Amplitude and duration of the movement-related cortical potential (MRCP) was measured from Cz. Electromyography (EMG) of biceps femoris (BF) and rectus femoris (RF) were collected. RESULTS: There were no differences between legs in stepping speed, MRCP or EMG parameters. The MRCPs when stepping with the paretic leg and the non-paretic leg were correlated. When the paretic leg was stepping, the MRCP amplitude correlated with MRCP duration, indicating a longer planning time was accompanied by higher cognitive effort. Slow steppers had larger MRCP amplitudes stepping with the paretic leg and longer MRCP durations stepping with the non-paretic leg. CONCLUSIONS: MRCP measures suggest that motor planning for initiating stepping are similar regardless of which limb is stepping. Individuals who stepped slowly had greater MRCP amplitudes and durations for planning. SIGNIFICANCE: Individuals who step slowly may require more time and effort to plan a movement, which may compromise their safety in the community.


Asunto(s)
Electromiografía/métodos , Intención , Corteza Motora/fisiología , Movimiento/fisiología , Accidente Cerebrovascular/fisiopatología , Caminata/fisiología , Anciano , Anciano de 80 o más Años , Corteza Cerebral , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Equilibrio Postural/fisiología , Accidente Cerebrovascular/diagnóstico , Caminata/psicología
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