scholarly journals Neural stimulation and recording performance in human somatosensory cortex over 1500 days

2020 ◽  
Author(s):  
Christopher L. Hughes ◽  
Sharlene N. Flesher ◽  
Jeffrey M. Weiss ◽  
John E. Downey ◽  
Jennifer L. Collinger ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Somatosensory Cortex ◽  
Microelectrode Arrays ◽  
High Amplitude ◽  
Detection Thresholds ◽  
Cord Injury ◽  
Human Participant ◽  
Tactile Sensations ◽  
Over Time

AbstractObjectiveIntracortical microstimulation (ICMS) in somatosensory cortex can restore sensation to people who have lost it due to spinal cord injury or other conditions. One potential challenge for chronic ICMS is whether neural recording and stimulation can remain stable over many years. This is particularly relevant since the recording quality of implanted microelectrode arrays frequently experience degradation over time and stimulation safety has been considered a potential barrier to the clinical use of ICMS. Our objective is to evaluate stability of recordings on intracortical stimulated and non-stimulated electrodes in a human participant across a long period of implantation. Additionally, we would like to assess the ability to evoke sensations with ICMS over time.ApproachIn a study investigating intracortical implants for a bidirectional brain-computer interface, we implanted microelectrode arrays with sputtered iridium oxide tips in the somatosensory cortex of a human participant with a cervical spinal cord injury. We regularly stimulated through electrodes on these microelectrode arrays to evoke tactile sensations on the hand. Here, we quantify the stability of these electrodes in comparison to non-stimulated electrodes implanted in motor cortex over 1500 days in two ways: recorded signal quality and electrode impedances. Additionally, we quantify the perceptual stability of ICMS-evoked sensations with detection thresholds.Main resultsWe found that recording quality, as assessed by the number of electrodes with high-amplitude waveform recordings (> 100 µV), peak-to-peak voltage, noise, and signal-to-noise ratio, generally decreased over time on stimulated and non-stimulated electrodes. However, stimulated electrodes were much more likely to continue to record high-amplitude signals than non-stimulated electrodes. Interestingly, the detection thresholds for stimulus-evoked tactile sensations decreased over time from a median of 31.5 μA at Day 100 to 10.4 μA at Day 1500, with the most substantial changes occurring between Day 100 and Day 500.SignificanceThese results provide evidence that ICMS in human somatosensory cortex can be provided over long periods of time without deleterious effects on recording or stimulation capabilities. In fact, psychophysical sensitivity to stimulation improves over time and stimulation itself may promote more robust long-term neural recordings.

Intracortical Somatosensory Stimulation to Elicit Fingertip Sensations in an Individual With Spinal Cord Injury

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000013173
Author(s):  
Matthew Stephen Fifer ◽  
David P McMullen ◽  
Luke E Osborn ◽  
Tessy M Thomas ◽  
Breanne P Christie ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Pulse Amplitude ◽  
Electrode Arrays ◽  
Somatosensory Stimulation ◽  
Cord Injury ◽  
Human Participant ◽  
The Subject ◽  
Tactile Sensations ◽  
Clinical Trial Information

Background and Objectives:The restoration of touch to fingers and fingertips is critical to achieving dexterous neuroprosthetic control for individuals with sensorimotor dysfunction. However, localized fingertip sensations have not been evoked via intracortical microstimulation (ICMS).Methods:Using a novel intraoperative mapping approach, we implanted electrode arrays in the finger areas of left and right somatosensory cortex and delivered ICMS over a 2-year period in a human participant with spinal cord injury.Results:Stimulation evoked tactile sensations in 8 fingers, including fingertips, spanning both hands. Evoked percepts followed expected somatotopic arrangements. The subject was able to reliably identify up to 7 finger-specific sites spanning both hands in a finger discrimination task. The size of the evoked percepts was on average 33% larger than a fingerpad, as assessed via manual markings of a hand image. The size of the evoked percepts increased modestly with increased stimulation intensity, growing 21% as pulse amplitude increased from 20µA to 80µA. Detection thresholds were estimated on a subset of electrodes, with estimates of 9.2-35µA observed, roughly consistent with prior studies.Discussion:These results suggest that ICMS can enable the delivery of consistent and localized fingertip sensations during object manipulation by neuroprostheses for individuals with somatosensory deficits.Clinical Trial Information:This study is registered on ClinicalTrials.gov with identifier NCT03161067.

scholarly journals 10-Year Trends in Urine Testing and Treatment in Patients with Spinal Cord Injury: An Opportunity for Targeted Stewardship

2020 ◽  
Vol 41 (S1) ◽  
pp. s90-s90
Author(s):  
Alison Nelson ◽  
Kalpana Gupta ◽  
Judith Strymish ◽  
Maura Nee ◽  
Katherine Linsenmeyer
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Antibiotic Treatment ◽  
Urine Culture ◽  
Asymptomatic Bacteriuria ◽  
Routine Screening ◽  
Organizational Level ◽  
Cord Injury ◽  
Urine Testing ◽  
Over Time

Background: Guidelines regarding asymptomatic bacteriuria (ASB) have consistently recommended against screening and treatment in most circumstances. However, screening of patients with spinal cord injury (SCI) is common practice and in some cases is a formal protocol at the organizational level. A previous study found that more than one-third of patients with ASB detected on routine screening cultures performed at annual visits in 2012 received antibiotics. However, the role of antibiotic stewardship has become more prominent over the last decade. We hypothesized that diagnostic and therapeutic stewardship efforts may be impacting the practice of annual urine-culture screening for SCI patients. We evaluated urine culture screening and treatment rates over a 10-year period. Methods: Patients with SCI seen in the VA Boston HCS for an annual exam in 2018 were eligible for inclusion and formed the baseline cohort for this study. Annual visits for the cohort over a 10-year period (January 1, 2009–December 31, 2018) were included in the analysis. Electronic data collection and manual chart review were utilized to capture outcomes of interest including urine culture, antibiotic prescriptions and indication within 15 days, and documentation of urinary or infectious symptoms. The main outcomes were (1) rate of urine cultures performed ±3 days of the visit, (2) rate of antibiotic treatment in asymptomatic patients, and (3) trend over time of urine culturing and treating. The χ2 test for trend was used to compare rates over time. Results: In total, 1,962 annual visits were made by the 344 unique patients over the 10-year period and were available for analysis. Among these, 639 (32.6%) visits had a urine culture performed within 3 days. The proportion of visits with a collected culture decreased from (109 of 127) 85.8% of visits in 2009 to (65 of 338) 19.2% of visits in 2018, P ≤ .001 (Fig. 1). In the treatment analysis, 39 visits were excluded for active symptoms, concern for uncontrolled infection, or prophylaxis as antibiotic indication. Among 600 remaining screening cultures, 328 had a bacterial pathogen or >100,000 mixed colonies consistent with ASB. Overall, 51 patients (17%) received antimicrobials. The rate of antibiotic treatment for ASB did not significantly decrease over time pP = 0.79 (Fig. 2). Conclusions: Over a 10-year period of annual SCI visits, the proportion of visits with a urine culture performed as routine screening significantly and consistently decreased. However, the rate of treatment for positive urine cultures remained consistent. These data support targeted diagnostic stewardship in this population to reduce unnecessary antibiotic use.Funding: NoneDisclosures: None

scholarly journals Long term outcome of functional independence and quality of life after traumatic SCI in Germany

Spinal Cord ◽  
2021 ◽  
Author(s):  
Florian Möller ◽  
Rüdiger Rupp ◽  
Norbert Weidner ◽  
Christoph Gutenbrunner ◽  
Yorck B. Kalke ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Independence ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Cord Injury ◽  
Over Time

Abstract Study design Multicenter observational study. Objective To describe the long-term outcome of functional independence and quality of life (QoL) for individuals with traumatic and ischemic SCI beyond the first year after injury. Setting A multicenter study in Germany. Methods Participants of the European multicenter study about spinal cord injury (EMSCI) of three German SCI centers were included and followed over time by the German spinal cord injury cohort study (GerSCI). Individuals’ most recent spinal cord independence measure (SCIM) scores assessed by a clinician were followed up by a self-report (SCIM-SR) and correlated to selected items of the WHO short survey of quality of life (WHO-QoL-BREF). Results Data for 359 individuals were obtained. The average time passed the last clinical SCIM examination was 81.47 (SD 51.70) months. In total, 187 of the 359 received questionnaires contained a completely evaluable SCIM-SR. SCIM scores remained stable with the exception of reported management of bladder and bowel resulting in a slight decrease of SCIM-SR of −2.45 points (SD 16.81). SCIM-SR scores showed a significant correlation with the selected items of the WHO-QoL-BREF (p < 0.01) with moderate to strong influence. Conclusion SCIM score stability over time suggests a successful transfer of acquired independence skills obtained during primary rehabilitation into the community setting paralleled by positively related QoL measurements but bladder and bowel management may need special attention.

scholarly journals Spinal Cord Injury due to Tumour or Metastasis in Aragón, Northeastern Spain (1991–2008): Incidence, Time Trends, and Neurological Function

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Maayken Elizabeth Louise van den Berg ◽  
Juan M. Castellote ◽  
Jose Ignacio Mayordomo ◽  
Ignacio Mahillo-Fernandez ◽  
Jesus de Pedro-Cuesta
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Population Distribution ◽  
Primary Tumour ◽  
Temporal Trends ◽  
Health Resources ◽  
The Elderly ◽  
Incidence Rates ◽  
Cord Injury ◽  
Over Time

Purpose. Understanding the presentation of spinal cord injury (SCI) due to tumours considering population distribution and temporal trends is key to managing SCI health services. This study quantified incidence rates, function scores, and trends of SCI due to tumour or metastasis over an 18-year time period in a defined region in Spain. Methods. A retrospective cohort study included in-and outpatients with nontraumatic SCI due to tumour or metastasis admitted to a metropolitan hospital in Spain between 1991 and 2008. Main outcome measures were crude and age- and sex-adjusted incidence rates, tumour location and type, distribution by spinal level, neurological level of injury, and impairment ASIA scores. Results. Primary tumour or metastasis accounted for 32.5% of nontraumatic SCI with an incidence rate of 4.1 per million population. Increasing rates with age and over time were observed. Major pathology groups were intradural-extramedullary masses from which meningiomas and neurinomas accounted for 40%. Lesions were mostly incomplete with predominant ASIA Grade D. Conclusions. Increasing incidence rates of tumour-related SCI over time in the middle-aged and the elderly suggest a growing need for neurooncology health resources in the future.

scholarly journals Finger somatotopy is preserved after tetraplegia but deteriorates over time

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Sanne Kikkert ◽  
Dario Pfyffer ◽  
Michaela Verling ◽  
Patrick Freund ◽  
Nicole Wenderoth
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Observational Study ◽  
Sensorimotor Cortex ◽  
Structural Mri ◽  
Finger Movement ◽  
Functional Connections ◽  
Cord Injury ◽  
Primary Sensorimotor Cortex ◽  
Over Time

Previous studies showed reorganised and/or altered activity in the primary sensorimotor cortex after a spinal cord injury (SCI), suggested to reflect abnormal processing. However, little is known about whether somatotopically-specific representations can be activated despite reduced or absent afferent hand inputs. In this observational study we used functional MRI and an (attempted) finger movement task in tetraplegic patients to characterise the somatotopic hand layout in primary somatosensory cortex. We further used structural MRI to assess spared spinal tissue bridges. We found that somatotopic hand representations can be activated through attempted finger movements in absence of sensory and motor hand functioning, and no spared spinal tissue bridges. Such preserved hand somatotopy could be exploited by rehabilitation approaches that aim to establish new hand-brain functional connections after SCI (e.g., neuroprosthetics). However, over years since SCI the hand representation somatotopy deteriorated, suggesting that somatotopic hand representations are more easily targeted within the first years after SCI.

Long-term spinal cord injury: Functional changes over time

1993 ◽  
Vol 74 (10) ◽  
pp. 1030-1034 ◽  
Author(s):  
Kenneth A. Gerhart ◽  
Ebba Bergstrom ◽  
Susan W. Charlifue ◽  
Robert R. Menter ◽  
Gale G. Whiteneck
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Changes ◽  
Cord Injury ◽  
Changes Over Time ◽  
Over Time

scholarly journals Classification challenges of the 2019 revised International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI)

Spinal Cord ◽  
2021 ◽  
Author(s):  
Steven Kirshblum ◽  
Mary Schmidt Read ◽  
Rüdiger Rupp
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Injury ◽  
International Standards ◽  
Correct Classification ◽  
International Expert ◽  
Cord Injury ◽  
Over Time

Abstract Study design Retrospective review of ISNCSCI datasets. Objectives To discuss the correct classification of ISNCSCI datasets considered as challenging. Setting International expert collaboration. Methods The International Standards Committee of the American Spinal Injury Association (ASIA) receives challenging case scenarios regarding the International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI). Among those cases received, sample cases representing different categories of typical classification difficulties were identified by members of the International Standards committee. Results From the cases received, five sample cases were identified as representative for publication. These cases are related to the correct classification in the presence of non-SCI related conditions, the determination of motor zones of partial preservation in regions with no myotomes to test, the classification of the ASIA Impairment Scale in patients with substantial motor function below the motor level but no sacral sparing, the inclusion of non-key muscle functions in the classification of sensory incomplete individuals, and the correct classification of individuals with an amputation. Conclusion Presenting cases with challenging classifications, along with responses and explanations, will serve spinal cord injury professionals to better understand and utilize the ISNCSCI classification. As the ISNCSCI endorsed by ASIA and the International Spinal Cord Society (ISCoS) evolves over time, such resources are important to clarify inquiries from the spinal cord injury community and to understand the rationale for revisions.

scholarly journals Lower urinary changes over time in suprasacral spinal cord injury

Spinal Cord ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 326-329 ◽  
Author(s):  
D D Cardenas ◽  
M E Mayo ◽  
L R Turner
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cord Injury ◽  
Changes Over Time ◽  
Over Time ◽  
Lower Urinary
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