%0 Journal Article %J Exp Brain Res %D 2023 %T Effects of active and sham tDCS on the soleus H-reflex during standing. %A McCane, Lynn M %A Wolpaw, Jonathan R %A Thompson, Aiko K %K Adult %K Evoked Potentials, Motor %K H-Reflex %K Humans %K Muscle, Skeletal %K Standing Position %K Transcranial Direct Current Stimulation %X

Weak transcranial direct current stimulation (tDCS) is known to affect corticospinal excitability and enhance motor skill acquisition, whereas its effects on spinal reflexes in actively contracting muscles are yet to be established. Thus, in this study, we examined the acute effects of Active and Sham tDCS on the soleus H-reflex during standing. In fourteen adults without known neurological conditions, the soleus H-reflex was repeatedly elicited at just above M-wave threshold throughout 30 min of Active (N = 7) or Sham (N = 7) 2-mA tDCS over the primary motor cortex in standing. The maximum H-reflex (H) and M-wave (M) were also measured before and immediately after 30 min of tDCS. The soleus H-reflex amplitudes became significantly larger (by 6%) ≈1 min into Active or Sham tDCS and gradually returned toward the pre-tDCS values, on average, within 15 min. With Active tDCS, the amplitude reduction from the initial increase appeared to occur more swiftly than with Sham tDCS. An acute temporary increase in the soleus H-reflex amplitude within the first minute of Active and Sham tDCS found in this study indicates a previously unreported effect of tDCS on the H-reflex excitability. The present study suggests that neurophysiological characterization of Sham tDCS effects is just as important as investigating Active tDCS effects in understanding and defining acute effects of tDCS on the excitability of spinal reflex pathways.

%B Exp Brain Res %V 241 %P 1611-1622 %8 06/2023 %G eng %N 6 %R 10.1007/s00221-023-06624-7 %0 Journal Article %J Amyotroph Lateral Scler Frontotemporal Degener %D 2014 %T Brain-computer interface (BCI) evaluation in people with amyotrophic lateral sclerosis. %A McCane, Lynn M %A Sellers, Eric W %A Dennis J. McFarland %A Mak, Joseph N %A Carmack, C Steve %A Zeitlin, Debra %A Jonathan Wolpaw %A Theresa M Vaughan %K Adult %K Aged %K Amyotrophic Lateral Sclerosis %K Biofeedback, Psychology %K brain-computer interfaces %K Communication Disorders %K Electroencephalography %K Event-Related Potentials, P300 %K Female %K Humans %K Male %K Middle Aged %K Online Systems %K Photic Stimulation %K Psychomotor Performance %K Reaction Time %X Brain-computer interfaces (BCIs) might restore communication to people severely disabled by amyotrophic lateral sclerosis (ALS) or other disorders. We sought to: 1) define a protocol for determining whether a person with ALS can use a visual P300-based BCI; 2) determine what proportion of this population can use the BCI; and 3) identify factors affecting BCI performance. Twenty-five individuals with ALS completed an evaluation protocol using a standard 6 × 6 matrix and parameters selected by stepwise linear discrimination. With an 8-channel EEG montage, the subjects fell into two groups in BCI accuracy (chance accuracy 3%). Seventeen averaged 92 (± 3)% (range 71-100%), which is adequate for communication (G70 group). Eight averaged 12 (± 6)% (range 0-36%), inadequate for communication (L40 subject group). Performance did not correlate with disability: 11/17 (65%) of G70 subjects were severely disabled (i.e. ALSFRS-R < 5). All L40 subjects had visual impairments (e.g. nystagmus, diplopia, ptosis). P300 was larger and more anterior in G70 subjects. A 16-channel montage did not significantly improve accuracy. In conclusion, most people severely disabled by ALS could use a visual P300-based BCI for communication. In those who could not, visual impairment was the principal obstacle. For these individuals, auditory P300-based BCIs might be effective. %B Amyotroph Lateral Scler Frontotemporal Degener %V 15 %P 207-15 %8 06/2014 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/24555843 %N 3-4 %R 10.3109/21678421.2013.865750 %0 Journal Article %J J Neural Eng %D 2014 %T A practical, intuitive brain-computer interface for communicating 'yes' or 'no' by listening. %A Jeremy Jeremy Hill %A Ricci, Erin %A Haider, Sameah %A McCane, Lynn M %A Susan M Heckman %A Jonathan Wolpaw %A Theresa M Vaughan %K Adult %K Aged %K Algorithms %K Auditory Perception %K brain-computer interfaces %K Communication Aids for Disabled %K Electroencephalography %K Equipment Design %K Equipment Failure Analysis %K Female %K Humans %K Male %K Man-Machine Systems %K Middle Aged %K Quadriplegia %K Treatment Outcome %K User-Computer Interface %X OBJECTIVE: Previous work has shown that it is possible to build an EEG-based binary brain-computer interface system (BCI) driven purely by shifts of attention to auditory stimuli. However, previous studies used abrupt, abstract stimuli that are often perceived as harsh and unpleasant, and whose lack of inherent meaning may make the interface unintuitive and difficult for beginners. We aimed to establish whether we could transition to a system based on more natural, intuitive stimuli (spoken words 'yes' and 'no') without loss of performance, and whether the system could be used by people in the locked-in state. APPROACH: We performed a counterbalanced, interleaved within-subject comparison between an auditory streaming BCI that used beep stimuli, and one that used word stimuli. Fourteen healthy volunteers performed two sessions each, on separate days. We also collected preliminary data from two subjects with advanced amyotrophic lateral sclerosis (ALS), who used the word-based system to answer a set of simple yes-no questions. MAIN RESULTS: The N1, N2 and P3 event-related potentials elicited by words varied more between subjects than those elicited by beeps. However, the difference between responses to attended and unattended stimuli was more consistent with words than beeps. Healthy subjects' performance with word stimuli (mean 77% ± 3.3 s.e.) was slightly but not significantly better than their performance with beep stimuli (mean 73% ± 2.8 s.e.). The two subjects with ALS used the word-based BCI to answer questions with a level of accuracy similar to that of the healthy subjects. SIGNIFICANCE: Since performance using word stimuli was at least as good as performance using beeps, we recommend that auditory streaming BCI systems be built with word stimuli to make the system more pleasant and intuitive. Our preliminary data show that word-based streaming BCI is a promising tool for communication by people who are locked in. %B J Neural Eng %V 11 %P 035003 %8 06/2014 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/24838278 %N 3 %R 10.1088/1741-2560/11/3/035003