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1.
medRxiv ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38699312

RESUMO

As rehabilitation advances into the era of digital health, remote monitoring of physical activity via wearable devices has the potential to change how we provide care. However, uncertainties about patient adherence and the significant resource requirements needed create challenges to adoption of remote monitoring into clinical care. Here we aim to determine the impact of a novel digital application to overcome these barriers. The Rehabilitation Remote Monitoring Application (RRMA) automatically extracts data about physical activity collected via a Fitbit device, screens the data for adherence, and contacts the participant if adherence is low. We compare adherence and estimate the resources required (i.e., time and financial) to perform remote monitoring of physical activity with and without the RRMA in two patient groups. Seventy-three individuals with stroke or chronic obstructive pulmonary disease completed 28 days of monitoring physical activity with the RRMA, while 62 individuals completed 28 days with the data flow processes being completed manually. Adherence (i.e., the average percentage of the day that the device was worn) was similar between groups (p=0.85). However, the RRMA saved an estimated 123.8 minutes or $50.24 per participant month when compared to manual processes. These results demonstrate that automated technologies like the RRMA can maintain patient adherence to remote monitoring of physical activity while reducing the time and financial resources needed. Applications like the RRMA can facilitate the adoption of remote monitoring in rehabilitation by reducing barriers related to adherence and resource requirements.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38722244

RESUMO

OBJECTIVE: Sports-related concussion management in collegiate athletes has been focused on return-to-play. However, resuming schoolwork without a gradual stepwise reintroduction contributes to symptom exacerbation, delayed recovery, and adverse academic performance. Return-to-learn guidelines are limited by a lack of sensitivity in methods monitoring cognitive function. This study evaluated 2 neuropsychological tests, the Sternberg test and the Paced Auditory Serial Addition Test (PASAT), with high ceilings for sensitivity to deficits in speed of information processing, cognitive efficiency, and complex attention. SETTING: Academic center research laboratory. PARTICIPANTS: We recruited 56 male and female collegiate contact and noncontact sports athletes. They were categorized into as follows: (1) nonconcussed (n = 23; 7F, 16M); (2) chronic (n = 21; 4F, 17M), at least 1 year from their last concussion; and (3) acute (n = 12; 1F, 11M), within 2 weeks from concussion. DESIGN: Observational cohort study. MAIN MEASURES: The PASAT assesses complex attention. The Sternberg test examines processing speed and cognitive efficiency. Cognitive difficulty increases with progression through the tasks for both the PASAT and the Sternberg test. The mean outcome differences of the 3 groups (nonconcussed, acute, and chronic) across the 3 or 4 conditions (difficulty level) were measured with repeated-measures analysis of variance and subsequent pairwise comparison. RESULTS: For processing speed (Sternberg reaction time), the acute group responded slower than the chronic group on the medium (P = .021, Bonferroni corrected) and hard difficulty tasks (P = .030, Bonferroni corrected). For cognitive efficiency (Sternberg reaction time variability), the acute group had increased reaction time variability compared with the chronic group on the medium difficulty task (P = .04, Bonferroni corrected). For complex attention (PASAT omissions), there was a difference between the acute and nonconcussed groups on the moderate-hard difficulty trial (P = .023, least significant difference [LSD] corrected) and between the acute and chronic groups for hard difficulty trial (P = .020, LSD corrected). The acute group performed worse, with progressively shorter interstimulus intervals. CONCLUSION: Neuropsychological testing without ceiling effects can capture higher-level cognitive dysfunction and use of such tests can contribute to the understanding of how collegiate athletes are affected by SRC. Future studies can investigate optimal testing batteries that include neuropsychological testing with high ceilings and whether the pattern of performance has implications for the return-to-learn process after SRC in the college setting.

3.
Int J Stroke ; 19(2): 145-157, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37824726

RESUMO

BACKGROUND AND AIMS: The purpose of this Third Stroke Recovery and Rehabilitation Roundtable (SRRR3) was to develop consensus recommendations to address outstanding barriers for the translation of preclinical and clinical research using the non-invasive brain stimulation (NIBS) techniques Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) and provide a roadmap for the integration of these techniques into clinical practice. METHODS: International NIBS and stroke recovery experts (N = 18) contributed to the consensus process. Using a nominal group technique, recommendations were reached via a five-stage process, involving a thematic survey, two priority ranking surveys, a literature review and an in-person meeting. RESULTS AND CONCLUSIONS: Results of our consensus process yielded five key evidence-based and feasibility barriers for the translation of preclinical and clinical NIBS research, which were formulated into five core consensus recommendations. Recommendations highlight an urgent need for (1) increased understanding of NIBS mechanisms, (2) improved methodological rigor in both preclinical and clinical NIBS studies, (3) standardization of outcome measures, (4) increased clinical relevance in preclinical animal models, and (5) greater optimization and individualization of NIBS protocols. To facilitate the implementation of these recommendations, the expert panel developed a new SRRR3 Unified NIBS Research Checklist. These recommendations represent a translational pathway for the use of NIBS in stroke rehabilitation research and practice.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Estimulação Transcraniana por Corrente Contínua , Animais , Humanos , Acidente Vascular Cerebral/terapia , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Transcraniana por Corrente Contínua/métodos , Encéfalo/fisiologia , Consenso , Estimulação Magnética Transcraniana/métodos , Fenômenos Magnéticos
4.
Neurorehabil Neural Repair ; 38(1): 19-29, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37837350

RESUMO

BACKGROUND AND AIMS: The purpose of this Third Stroke Recovery and Rehabilitation Roundtable (SRRR3) was to develop consensus recommendations to address outstanding barriers for the translation of preclinical and clinical research using the non-invasive brain stimulation (NIBS) techniques Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) and provide a roadmap for the integration of these techniques into clinical practice. METHODS: International NIBS and stroke recovery experts (N = 18) contributed to the consensus process. Using a nominal group technique, recommendations were reached via a five-stage process, involving a thematic survey, two priority ranking surveys, a literature review and an in-person meeting. RESULTS AND CONCLUSIONS: Results of our consensus process yielded five key evidence-based and feasibility barriers for the translation of preclinical and clinical NIBS research, which were formulated into five core consensus recommendations. Recommendations highlight an urgent need for (1) increased understanding of NIBS mechanisms, (2) improved methodological rigor in both preclinical and clinical NIBS studies, (3) standardization of outcome measures, (4) increased clinical relevance in preclinical animal models, and (5) greater optimization and individualization of NIBS protocols. To facilitate the implementation of these recommendations, the expert panel developed a new SRRR3 Unified NIBS Research Checklist. These recommendations represent a translational pathway for the use of NIBS in stroke rehabilitation research and practice.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Estimulação Transcraniana por Corrente Contínua , Animais , Humanos , Reabilitação do Acidente Vascular Cerebral/métodos , Estimulação Transcraniana por Corrente Contínua/métodos , Encéfalo/fisiologia , Consenso , Acidente Vascular Cerebral/terapia , Estimulação Magnética Transcraniana/métodos , Fenômenos Magnéticos
5.
Sci Rep ; 13(1): 21394, 2023 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-38123594

RESUMO

The cerebellum has demonstrated a critical role during adaptation in motor learning. However, the extent to which it can contribute to the skill acquisition of complex real-world tasks remains unclear. One particularly challenging application in terms of motor activities is robotic surgery, which requires surgeons to complete complex multidimensional visuomotor tasks through a remotely operated robot. Given the need for high skill proficiency and the lack of haptic feedback, there is a pressing need for understanding and improving skill development. We investigated the effect of cerebellar transcranial direct current stimulation applied during the execution of a robotic surgery training task. Study participants received either real or sham stimulation while performing a needle driving task in a virtual (simulated) and a real-world (actual surgical robot) setting. We found that cerebellar stimulation significantly improved performance compared to sham stimulation at fast (more demanding) execution speeds in both virtual and real-world training settings. Furthermore, participants that received cerebellar stimulation more effectively transferred the skills they acquired during virtual training to the real world. Our findings underline the potential of non-invasive brain stimulation to enhance skill learning and transfer in real-world relevant tasks and, more broadly, its potential for improving complex motor learning.


Assuntos
Procedimentos Cirúrgicos Robóticos , Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Destreza Motora/fisiologia , Aprendizagem/fisiologia , Cerebelo/fisiologia
6.
Brain Stimul ; 16(5): 1232-1239, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37595834

RESUMO

Subcortical motor pathways, such as the reticulospinal tract, are critical for producing and modulating voluntary movements and have been implicated in neurological conditions. Previous research has described the presence of ipsilateral motor evoked potentials (iMEPs) in the arm to transcranial magentic stimulation (TMS), and suggested they could be mediated by the uncrossed corticospinal tract or by ipsilateral cortico-reticulospinal connections. Here, we sought to elucidate the role of the reticulospinal tract in mediating iMEPs by assessing their modulation by a startling acoustic stimulus and mapping these responses across multiple upper limb effectors. In a first experiment, we delivered TMS at various intervals (1, 5, 10 and 15 ms) after a startling acoustic stimulus, known to excite the reticular formation, to elicit iMEPs in the arm. We observed robust facilitation of iMEP area when startle conditioning preceded TMS at the 10 ms interval. In a second experiment, we replicated our findings showing that both the area and number of iMEPs in the arm increases with startle conditioning. Using this technique, we observed that iMEPs are more prominent in the arm compared with the hand. In a third experiment, we also observed greater presence of iMEPs in flexor compared with extensor muscles. Together, these findings are consistent with properties of the reticulospinal tract observed in animals, suggesting that iMEPs primarily reflect reticulospinal activity. Our findings imply that we can use this approach to track modulation of cortico-reticulospinal excitability following interventions or neurological conditions where the reticulospinal tract may be involved in motor recovery.


Assuntos
Músculo Esquelético , Tratos Piramidais , Humanos , Vias Eferentes , Tratos Piramidais/fisiologia , Músculo Esquelético/fisiologia , Mãos , Potencial Evocado Motor/fisiologia , Estimulação Magnética Transcraniana/métodos , Eletromiografia/métodos
7.
Digit Health ; 9: 20552076231176160, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37214659

RESUMO

Objective: Clinical implementation of remote monitoring of human function requires an understanding of its feasibility. We evaluated adherence and the resources required to monitor physical, cognitive, and psychosocial function in individuals with either chronic obstructive pulmonary disease or stroke during a three-month period. Methods: Seventy-three individuals agreed to wear a Fitbit to monitor physical function and to complete monthly online assessments of cognitive and psychosocial function. During a three-month period, we measured adherence to monitoring (1) physical function using average daily wear time, and (2) cognition and psychosocial function using the percentage of assessments completed. We measured the resources needed to promote adherence as (1) the number of participants requiring at least one reminder to synchronize their Fitbit, and (2) the number of reminders needed for each completed cognitive and psychosocial assessment. Results: After accounting for withdrawals, the average daily wear time was 77.5 ± 19.9% of the day and did not differ significantly between months 1, 2, and 3 (p = 0.30). To achieve this level of adherence, 64.9% of participants required at least one reminder to synchronize their device. Participants completed 61.0% of the cognitive and psychosocial assessments; the portion of assessments completed each month didnot significantly differ (p = 0.44). Participants required 1.13 ± 0.57 reminders for each completed assessment. Results did not differ by disease diagnosis. Conclusions: Remote monitoring of human function in individuals with either chronic obstructive pulmonary disease or stroke is feasible as demonstrated by high adherence. However, the number of reminders required indicates that careful consideration must be given to the resources available to obtain high adherence.

8.
J Neurosci ; 43(17): 3094-3106, 2023 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-36914263

RESUMO

Fatigue is the subjective sensation of weariness, increased sense of effort, or exhaustion and is pervasive in neurologic illnesses. Despite its prevalence, we have a limited understanding of the neurophysiological mechanisms underlying fatigue. The cerebellum, known for its role in motor control and learning, is also involved in perceptual processes. However, the role of the cerebellum in fatigue remains largely unexplored. We performed two experiments to examine whether cerebellar excitability is affected after a fatiguing task and its association with fatigue. Using a crossover design, we assessed cerebellar inhibition (CBI) and perception of fatigue in humans before and after "fatigue" and "control" tasks. Thirty-three participants (16 males, 17 females) performed five isometric pinch trials with their thumb and index finger at 80% maximum voluntary capacity (MVC) until failure (force <40% MVC; fatigue) or at 5% MVC for 30 s (control). We found that reduced CBI after the fatigue task correlated with a milder perception of fatigue. In a follow-up experiment, we investigated the behavioral consequences of reduced CBI after fatigue. We measured CBI, perception of fatigue, and performance during a ballistic goal-directed task before and after the same fatigue and control tasks. We replicated the observation that reduced CBI after the fatigue task correlated with a milder perception of fatigue and found that greater endpoint variability after the fatigue task correlated with reduced CBI. The proportional relation between cerebellar excitability and fatigue indicates a role of the cerebellum in the perception of fatigue, which might come at the expense of motor control.SIGNIFICANCE STATEMENT Fatigue is one of the most common and debilitating symptoms in neurologic, neuropsychiatric, and chronic illnesses. Despite its epidemiological importance, there is a limited understanding of the neurophysiological mechanisms underlying fatigue. In a series of experiments, we demonstrate that decreased cerebellar excitability relates to lesser physical fatigue perception and worse motor control. These results showcase the role of the cerebellum in fatigue regulation and suggest that fatigue- and performance-related processes might compete for cerebellar resources.


Assuntos
Cerebelo , Aprendizagem , Feminino , Humanos , Masculino , Cerebelo/fisiologia , Eletromiografia/métodos , Inibição Psicológica , Aprendizagem/fisiologia , Percepção , Estimulação Magnética Transcraniana/métodos , Estudos Cross-Over
10.
bioRxiv ; 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36747674

RESUMO

Background: Neurorehabilitation approaches are frequently predicated on motor learning principles. However, much is left to be understood of how different kinds of motor learning are affected by stroke causing hemiparesis. Here we asked if two kinds of motor learning often employed in rehabilitation, (1) reinforcement learning and (2) error-based adaptation, are altered at different times after stroke. Methods: In a cross-sectional design, we compared learning in two groups of patients with stroke, matched for their baseline motor execution deficit on the paretic side. The early group was tested within 3 months following stroke (N = 35) and the late group was tested more than 6 months after stroke (N = 30). Two types of task were studied: one based on reinforcement learning and the other on error-based learning. Results: We found that reinforcement learning was impaired in the early but not the late group, whereas error-based learning was unaffected compared to controls. These findings could not be attributed to differences in baseline execution, cognitive impairment, gender, age, or lesion volume and location. Conclusions: The presence of a specific impairment in reinforcement learning in the first 3 months after stroke has important implications for rehabilitation. It might be necessary to either increase the amount of reinforcement feedback given early or even delay onset of certain forms of rehabilitation training, e.g., like constraint-induced movement therapy, and instead emphasize others forms of motor learning in this early time period. A deeper understanding of stroke-related changes in motor learning capacity has the potential to facilitate the development of new, more precise treatment interventions.

11.
Am J Phys Med Rehabil ; 102(2): 159-165, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634238

RESUMO

ABSTRACT: Environmental scans determine trends in an organization's or field's internal and external environment. The results can help shape goals, inform strategic decision making, and direct future actions. The Association of Academic Physiatrists convened a strategic planning group in 2020, composed of physiatrists representing a diversity of professional roles, career stages, race and ethnicity, gender, disability status, and geographic areas of practice. This strategic planning group performed an environmental scan to assess the forces, trends, challenges, and opportunities affecting both the Association of Academic Physiatrists and the entire field of academic physiatry (also known as physical medicine and rehabilitation, physical and rehabilitation medicine, and rehabilitation medicine). This article presents aspects of the environmental scan thought to be most pertinent to the field of academic physiatry organized within the following five themes: (1) Macro/Societal Trends, (2) Technological Advancements, (3) Diversity and Global Outreach, (4) Economy, and (5) Education/Learning Environment. The challenges and opportunities presented here can provide a roadmap for the field to thrive within the complex and evolving healthcare systems in the United States and globally.


Assuntos
Internato e Residência , Medicina , Medicina Física e Reabilitação , Humanos , Estados Unidos , Educação de Pós-Graduação em Medicina , Atenção à Saúde
13.
Am J Phys Med Rehabil ; 102(2S Suppl 1): S56-S60, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634332

RESUMO

ABSTRACT: Functional recovery and the response to rehabilitation interventions after stroke are highly variable. Understanding this variability will promote precision rehabilitation for stroke, allowing us to deliver targeted interventions to the right person at the right time. Capitalizing on large, heterogeneous data sets, such as those generated through clinical care and housed within the electronic health record, can lead to understanding of poststroke variability. However, accessing data from the electronic health record can be challenging because of data quality, privacy concerns, and the resources required for data extraction. Therefore, creating infrastructure that overcomes these challenges and contributes to a learning health system is needed to achieve precision rehabilitation after stroke. We describe the creation of a Precision Rehabilitation Data Repository that facilitates access to systematically collected data from the electronic health record as part of a learning health system to drive precision rehabilitation. Specifically, we describe the process of (1) standardizing the documentation of functional assessments, (2) obtaining regulatory approval, (3) defining the patient cohort, and (4) extracting data for the Precision Rehabilitation Data Repository. The development of similar infrastructures at other institutions can help generate large, heterogeneous data sets to drive poststroke care toward precision rehabilitation, thereby maximizing poststroke function within an efficient healthcare system.


Assuntos
Sistema de Aprendizagem em Saúde , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Modalidades de Fisioterapia , Recuperação de Função Fisiológica
14.
Am J Phys Med Rehabil ; 102(2S Suppl 1): S79-S84, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36634336

RESUMO

ABSTRACT: Motor, speech, and cognitive impairments are the most common consequences of neurological disorders. There has been an increasing interest in the use of noninvasive brain stimulation techniques such as transcranial direct current stimulation and transcranial magnetic stimulation to augment the effects of neurorehabilitation. Numerous research studies have shown that transcranial direct current stimulation and transcranial magnetic stimulation are highly promising neuromodulation tools that can work as adjuvants to standard neurorehabilitation services, including physical therapy, occupational therapy, and speech-language pathology. However, to date, there are vast differences in methodology in studies including noninvasive brain stimulation parameters, patient characteristics, time point of intervention after injury, and outcome measures, making it difficult to translate and implement transcranial direct current stimulation and transcranial magnetic stimulation in the clinical setting. Despite this, a series of principles are thought to underlie the effectiveness of noninvasive brain stimulation techniques. We developed a noninvasive brain stimulation rehabilitation program using these principles to provide best practices for applying transcranial direct current stimulation and/or transcranial magnetic stimulation as rehabilitation adjuvants in the clinical setting to help improve neurorehabilitation outcomes. This article outlines our approach, philosophy, and experience.


Assuntos
Reabilitação Neurológica , Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Pacientes Ambulatoriais , Estimulação Magnética Transcraniana/métodos , Encéfalo
15.
Neuroscience ; 513: 54-63, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36708800

RESUMO

The lateral prefrontal cortex (PFC) plays a variety of crucial roles in higher-order cognitive functions. Previous works have attempted to modulate lateral PFC function by applying non-invasive transcranial direct current stimulation (tDCS) and demonstrated positive effects on performance of tasks involving cognitive processes. The neurophysiological underpinning of the stimulation effects, however, remain poorly understood. Here, we explored the neurophysiological after-effects of tDCS over the lateral PFC by assessing changes in the magnitude of interhemispheric inhibition from the lateral PFC to the contralateral primary motor cortex (PFC-M1 IHI). Using a dual-site transcranial magnetic stimulation paradigm, we assessed PFC-M1 IHI before and after the application of tDCS over the right lateral PFC. We conducted a double-blinded, crossover, and counterbalanced design where 15 healthy volunteers participated in three sessions during which they received either anodal, cathodal, and sham tDCS. In order to determine whether PFC-M1 IHI could be modulated at all, we completed the same assessment on a separate group of 15 participants as they performed visuo-motor reaction tasks that likely engage the lateral PFC. The results showed that tDCS over the right lateral PFC did not modulate the magnitude of PFC-M1 IHI, whereas connectivity changed when Go/NoGo decisions were implemented in reactions during the motor tasks. Although PFC-M1 IHI is sensitive enough to be modulated by behavioral manipulations, tDCS over the lateral PFC does not have substantial modulatory effects on PFC to M1 functional connectivity, or at least not to the degree that can be detected with this measure.


Assuntos
Córtex Motor , Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Córtex Motor/fisiologia , Estimulação Magnética Transcraniana/métodos , Córtex Pré-Frontal/fisiologia , Cognição
16.
Front Neurorobot ; 16: 918001, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35837250

RESUMO

Advances in intelligent robotic systems and brain-machine interfaces (BMI) have helped restore functionality and independence to individuals living with sensorimotor deficits; however, tasks requiring bimanual coordination and fine manipulation continue to remain unsolved given the technical complexity of controlling multiple degrees of freedom (DOF) across multiple limbs in a coordinated way through a user input. To address this challenge, we implemented a collaborative shared control strategy to manipulate and coordinate two Modular Prosthetic Limbs (MPL) for performing a bimanual self-feeding task. A human participant with microelectrode arrays in sensorimotor brain regions provided commands to both MPLs to perform the self-feeding task, which included bimanual cutting. Motor commands were decoded from bilateral neural signals to control up to two DOFs on each MPL at a time. The shared control strategy enabled the participant to map his four-DOF control inputs, two per hand, to as many as 12 DOFs for specifying robot end effector position and orientation. Using neurally-driven shared control, the participant successfully and simultaneously controlled movements of both robotic limbs to cut and eat food in a complex bimanual self-feeding task. This demonstration of bimanual robotic system control via a BMI in collaboration with intelligent robot behavior has major implications for restoring complex movement behaviors for those living with sensorimotor deficits.

17.
Neurobiol Aging ; 118: 9-12, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35810524

RESUMO

Effective connectivity between the cerebellum and primary motor cortex (M1) is critical for motor learning and motor control. Despite evidence of cerebellar atrophy and declines in motor learning and motor control with advanced age, recent behavioral studies indicate that cerebellar-dependent motor learning processes are preserved or even enhanced in older adults. However, physiological evidence of heightened cerebellar excitability leading to strengthened cerebellar-M1 connectivity with advanced age is lacking. Here, we used transcranial magnetic stimulation to assess age-related effects on cerebellar inhibition, a measure of cerebellar-M1 connectivity, in 20 young and 19 older adults. We observed stronger cerebellar inhibition in older compared with young adults. The behavioral implications of strengthened cerebellar inhibition with advanced age found in this study remain to be determined.


Assuntos
Córtex Motor , Idoso , Cerebelo/fisiologia , Potencial Evocado Motor/fisiologia , Humanos , Aprendizagem/fisiologia , Córtex Motor/fisiologia , Estimulação Magnética Transcraniana
18.
Brain Stimul ; 15(3): 881-888, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35644516

RESUMO

BACKGROUND: Intracortical microstimulation (ICMS) of somatosensory cortex can partially restore the sense of touch. Though ICMS bypasses much of the neuraxis, prior studies have found that conscious detection of touch elicited by ICMS lags behind the detection of cutaneous vibration. These findings may have been influenced by mismatched stimulus intensities, which can impact temporal perception. OBJECTIVE: Evaluate the relative latency at which intensity-matched vibration and ICMS are perceived by a human participant. METHODS: One person implanted with microelectrode arrays in somatosensory cortex performed reaction time and temporal order judgment (TOJ) tasks. To measure reaction time, the participant reported when he perceived vibration or ICMS. In the TOJ task, vibration and ICMS were sequentially presented and the participant reported which stimulus occurred first. To verify that the participant could distinguish between stimuli, he also performed a modality discrimination task, in which he indicated if he felt vibration, ICMS, or both. RESULTS: When vibration was matched in perceived intensity to high-amplitude ICMS, vibration was perceived, on average, 48 ms faster than ICMS. However, in the TOJ task, both sensations arose at comparable latencies, with points of subjective simultaneity not significantly different from zero. The participant could discriminate between tactile modalities above chance level but was more inclined to report feeling vibration than ICMS. CONCLUSIONS: The latencies of ICMS-evoked percepts are slower than their mechanical counterparts. However, differences in latencies are small, particularly when stimuli are matched for intensity, implying that ICMS-based somatosensory feedback is rapid enough to be effective in neuroprosthetic applications.


Assuntos
Córtex Somatossensorial , Vibração , Estimulação Elétrica , Humanos , Masculino , Microeletrodos , Córtex Somatossensorial/fisiologia , Tato/fisiologia
20.
Sci Rep ; 12(1): 10353, 2022 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-35725741

RESUMO

Understanding the cortical representations of movements and their stability can shed light on improved brain-machine interface (BMI) approaches to decode these representations without frequent recalibration. Here, we characterize the spatial organization (somatotopy) and stability of the bilateral sensorimotor map of forearm muscles in an incomplete-high spinal-cord injury study participant implanted bilaterally in the primary motor and sensory cortices with Utah microelectrode arrays (MEAs). We built representation maps by recording bilateral multiunit activity (MUA) and surface electromyography (EMG) as the participant executed voluntary contractions of the extensor carpi radialis (ECR), and attempted motions in the flexor carpi radialis (FCR), which was paralytic. To assess stability, we repeatedly mapped and compared left- and right-wrist-extensor-related activity throughout several sessions, comparing somatotopy of active electrodes, as well as neural signals both at the within-electrode (multiunit) and cross-electrode (network) levels. Wrist motions showed significant activation in motor and sensory cortical electrodes. Within electrodes, firing strength stability diminished as the time increased between consecutive measurements (hours within a session, or days across sessions), with higher stability observed in sensory cortex than in motor, and in the contralateral hemisphere than in the ipsilateral. However, we observed no differences at network level, and no evidence of decoding instabilities for wrist EMG, either across timespans of hours or days, or across recording area. While map stability differs between brain area and hemisphere at multiunit/electrode level, these differences are nullified at ensemble level.


Assuntos
Antebraço , Músculo Esquelético , Eletromiografia , Antebraço/fisiologia , Humanos , Movimento/fisiologia , Músculo Esquelético/fisiologia , Quadriplegia
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