Kenneth C. Chelette

Repetitive Transcranial Magnetic Stimulation for Tinnitus: A Case Study

Objectives/Hypothesis: Correlate subjective improvements in tinnitus severity with restoration of cortical symmetry and sustained attention after neuronavigated low‐frequency, repetitive transcranial magnetic stimulation (rTMS).

Sham transcranial magnetic stimulation using electrical stimulation of the scalp

BACKGROUND: Most methods of sham, repetitive transcranial magnetic stimulation (rTMS) fail to replicate the look, sound, and feel of active stimulation in the absence of a significant magnetic field. OBJECTIVE/HYPOTHESIS: To develop and validate a new method of sham rTMS appropriate for a double-blind, placebo-controlled study with subject crossover. METHODS: The look and sound of active rTMS was replicated using a matched, air-cooled sham TMS coil. Scalp muscle stimulation associated with rTMS was replicated using large rubber electrodes placed over selected muscles. The intensity and pulse width of electrical stimulation necessary to match 1-Hz rTMS was developed in one sample of normal subjects. The sham technique was validated in back-to-back comparisons with active rTMS in new samples of normal subjects who were either naïve or experienced with rTMS. RESULTS: Subjects naïve to TMS could not tell which type of stimulation was active or sham or which was electrical or magnetic. Naïve subjects incorrectly picked sham stimulation as active, when forced to choose, because electrical stimulation felt more focused than magnetic stimulation. Subjects experienced with TMS could correctly identify sham and active stimulation. Experimenters could detect subtle differences between conditions. CONCLUSIONS: This method of sham rTMS closely mimics the look, sound, and feel of active stimulation at 1Hz without creating a significant magnetic field. It is valid for use with naïve subjects and in crossover studies. It can accommodate differences in scalp muscle recruitment at different sites of stimulation, and it could potentially be used with higher frequency stimulation.

Maintenance Repetitive Transcranial Magnetic Stimulation Can Inhibit the Return of Tinnitus

Objectives/Hypothesis: A single patient was tested to examine the safety and feasibility of using maintenance sessions of low‐frequency repetitive transcranial magnetic stimulation (1 Hz rTMS) to reduce tinnitus loudness and prevent its return over time.

Variable changes in PET activity before and after rTMS treatment for tinnitus

The objective was to determine whether low‐frequency repetitive transcranial magnetic stimulation (rTMS) improves tinnitus by decreasing neural activity in auditory processing regions of the temporal cortex and the utility of positron emission tomography (PET) for targeting treatment.

Brain Stimulation Paired with Novel Locomotor Training with Robotic Gait Orthosis in Chronic Stroke: a Feasibility Study

OBJECTIVES 1) To investigate the feasibility of combining transcranial direct current stimulation (tDCS) to the lower extremity (LE) motor cortex with novel locomotor training to facilitate gait in subjects with chronic stroke and low ambulatory status, and 2) to obtain insight from study subjects and their caregivers to inform future trial design. METHODS Double-blind, randomized controlled study with additional qualitative exploratory descriptive design. One-month follow-up.10 subjects with stroke were recruited and randomized to active tDCS or sham tDCS for 12 sessions. Both groups participated in identical locomotor training with a robotic gait orthosis (RGO) following each tDCS session. RGO training protocol was designed to harness cortical neuroplasticity. Data analysis included assessment of functional and participation outcome measures and qualitative thematic analysis. RESULTS Eight subjects completed the study. Both groups demonstrated trends toward improvement, but the active tDCS group showed greater improvement than the sham group. Qualitative analyses indicated beneficial effects of this combined intervention. CONCLUSIONS It is feasible to combine tDCS targeting the LE motor cortex with our novel locomotor training. It appears that tDCS has the potential to enhance the effectiveness of gait training in chronic stroke. Insights from participants provide additional guidance in designing future trials.

Non-invasive brain stimulation and robot-assisted gait training after incomplete spinal cord injury: A randomized pilot study

BACKGROUND Locomotor training with a robot-assisted gait orthosis (LT-RGO) and transcranial direct current stimulation (tDCS) are interventions that can significantly enhance motor performance after spinal cord injury (SCI). No studies have investigated whether combining these interventions enhances lower extremity motor function following SCI. OBJECTIVE Determine whether active tDCS paired with LT-RGO improves lower extremity motor function more than a sham condition, in subjects with motor incomplete SCI. METHODS Fifteen adults with SCI received 36 sessions of either active (n = 9) or sham (n = 6) tDCS (20 minutes) preceding LT-RGO (1 hour). Outcome measures included manual muscle testing (MMT; primary outcome measure); 6-Minute Walk Test (6MinWT); 10-Meter Walk Test (10MWT); Timed Up and Go Test (TUG); Berg Balance Scale (BBS); and Spinal Cord Independence Measure-III (SCIM-III). RESULTS MMT showed significant improvements after active tDCS, with the most pronounced improvement in the right lower extremity. 10MWT, 6MinWT, and BBS showed improvement for both groups. TUG and SCIM-III showed improvement only for the sham tDCS group. CONCLUSION Pairing tDCS with LT-RGO can improve lower extremity motor function more than LT-RGO alone. Future research with a larger sample size is recommended to determine longer-term effects on motor function and activities of daily living.

Improvement in arousal, visual neglect, and perception of stimulus intensity following cold pressor stimulation

The relationship between arousal, perception, and visual neglect was examined in this case study. Cold pressor stimulation (CPS: immersing the foot in iced water) was used to manipulate arousal and to determine its effects on contralesional neglect, perception of stimulus intensity (magnitude estimation), reaction time, and an electrophysiological correlate of ascending reticular activating system activity (i.e., the P50 potential). Measures that normalized from baseline following CPS included contralesional neglect on a clock drawing test, perception of stimulus magnitude, and P50 amplitude. The P50 amplitude returned to its abnormally low baseline level 20 min after CPS ended, indicating that CPS increased arousal.

Long-term cortical reorganization following stroke in a single subject with severe motor impairment.

BACKGROUND Stroke continues to be a major public health concern in the United States. Motor recovery in the post-acute stages of stroke is possible due to neuroplasticity, or the capacity of the brain to reorganize. OBJECTIVE This case study tracks neuroplastic and motor change in a subject with severe hemiparesis following an extensive middle cerebral artery stroke. He had absence of ipsilesional motor evoked potentials in early evaluations. This report is unique in that the duration of follow-up evaluation extends nearly 2 years, with evaluations being performed at 7, 9, 10, 13, 20, and 21 months post-stroke. METHODS At each evaluation we used transcranial magnetic stimulation to track neuroplastic change and the Fugl-Meyer Assessment and the Wolf Motor Function Test to evaluate upper extremity motor performance. RESULTS The contralesional hemisphere showed dynamic change throughout the study period. In contrast, the ipsilesional hemisphere demonstrated notable change only between 13 and 21 months post-stroke, with the most dramatic change occurring between 20 and 21 months post-stroke. Motor performance generally improved throughout the study period. CONCLUSIONS Our findings demonstrate that substantial neuroplasticity-mediated motor recovery can occur nearly 2 years after stroke in an individual with severe post-stroke motor impairment.

Behavioral, Neurophysiological, and Descriptive Changes After Occupation-Based Intervention

OBJECTIVE We evaluated the effects of occupation-based intervention on poststroke upper-extremity (UE) motor recovery, neuroplastic change, and occupational performance in 1 research participant. METHOD A 55-yr-old man with chronic stroke and moderately impaired UE motor function participated in 15 sessions of occupation-based intervention in a hospital setting designed to simulate a home environment. We tested behavioral motor function (Fugl-Meyer Assessment, Stroke Impact Scale, Canadian Occupational Performance Measure) and neuroplasticity (transcranial magnetic stimulation [TMS]) at baseline and at completion of intervention. We collected descriptive data on occupational participation throughout the study. RESULTS All behavioral outcomes indicated clinically relevant improvement. TMS revealed bihemispheric corticomotor reorganization. Descriptive data revealed enhanced occupational performance. CONCLUSION Occupation-based intervention delivered in a hospital-based, homelike environment can lead to poststroke neuroplastic change, increased functional use of the affected UE, and improved occupational performance.

Nerve Stimulation Enhances Task-Oriented Training in Chronic, Severe Motor Deficit After Stroke A Randomized Trial

Background and Purpose— A sensory-based intervention called peripheral nerve stimulation can enhance outcomes of motor training for stroke survivors with mild-to-moderate hemiparesis. Further research is needed to establish whether this paired intervention can have benefit in cases of severe impairment (almost no active movement). Methods— Subjects with chronic, severe poststroke hemiparesis (n=36) were randomized to receive 10 daily sessions of either active or sham stimulation (2 hours) immediately preceding intensive task-oriented training (4 hours). Upper extremity movement function was assessed using Fugl–Meyer Assessment (primary outcome measure), Wolf Motor Function Test, and Action Research Arm Test at baseline, immediately post intervention and at 1-month follow-up. Results— Statistically significant difference between groups favored the active stimulation group on Fugl–Meyer at postintervention (95% confidence interval [CI], 1.1–6.9; P=0.008) and 1-month follow-up (95% CI, 0.6–8.3; P=0.025), Wolf Motor Function Test at postintervention (95% CI, −0.21 to −0.02; P=0.020), and Action Research Arm Test at postintervention (95% CI, 0.8–7.3; P=0.015) and 1-month follow-up (95% CI, 0.6–8.4; P=0.025). Only the active stimulation condition was associated with (1) statistically significant within-group benefit on all outcomes at 1-month follow-up and (2) improvement exceeding minimal detectable change, as well as minimal clinically significant difference, on ≥1 outcomes at ≥1 time points after intervention. Conclusions— After stroke, active peripheral nerve stimulation paired with intensive task–oriented training can effect significant improvement in severely impaired upper extremity movement function. Further confirmatory studies that consider a larger group, as well as longer follow-up, are needed. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT02633215.