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Completed

NCT Number: NCT06365086

Targeting Personalized Brain States Reflecting Strong and Weak Corticospinal Tract Output in Real-time

Transcranial magnetic stimulation (TMS) interventions could feasibly strengthen residual corticospinal tract (CST) connections and enhance recovery of paretic hand function after stroke. To maximize the therapeutic effects of such interventions, they must be delivered during poststroke brain activity patterns during which TMS best activates the residual corticospinal tract and enhances neural transmission within it (i.e., brain state-dependent TMS). In this study, the investigators will test the feasibility of real-time, personalized brain state-dependent TMS in neurotypical adults.

Participants will visit the laboratory for one day of testing. Upon arrival, participants will provide their informed consent; afterwards, they will complete eligibility screening. The investigators will then place recording electrodes on the scalp using a swim-type cap and on the left first dorsal interosseous, abductor pollicis brevis, and extensor digitorum communis muscles. After determining the location at which TMS best elicits muscle twitches in the left first dorsal interosseous, the investigators will determine the lowest possible intensity at which TMS elicits muscle twitches at least half of the time in this muscle. Then, the investigators will deliver 6 blocks of 100 single TMS pulses while the participant rests quietly with their eyes open; stimulation will be delivered at an intensity that is 20% greater than the lowest possible intensity at which TMS elicits muscle twitches at least half of the time. Afterwards, the investigators will use the muscle and brain activity recordings acquired during these 6 blocks to build a personalized mathematical model that identifies which patterns of brain activity correspond to the largest TMS-evoked muscle twitches. The investigators will then use this model to detect the occurrence of these brain activity patterns in real-time; when these patterns are detected, single TMS pulses will be delivered. Afterwards, all recording electrodes will be removed, participation will be complete, and participants will leave the laboratory.

The investigators will recruit a total of 16 neurotypical adults for this study.

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Key information

Conditions

Neurotypical Adults

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Texas at Austin

Austin, Texas, 78712, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Right-hand dominance
  • Willingness to participate
  • Ability to provide informed consent

Exclusion criteria

  • History of major neurological, orthopedic, psychiatric, or cardiovascular disease
  • Presence of contraindications to transcranial magnetic stimulation (TMS) or peripheral nerve stimulation (PNS), including:
  • history of adverse reactions to TMS or PNS
  • history of stroke or head injury
  • metal in head, eyes, neck, chest/trunk, or arms, including but not limited to shrapnel,
  • surgical clips, fragments from metalworking, fragments from welding
  • implanted devices
  • history of frequent and severe headaches or migraines
  • immediate family history of seizure or epilepsy
  • personal history of seizure or epilepsy
  • current, suspected, or planned pregnancy
  • current or recent (within the last 3 months) use of medications acting on the central nervous system, including but not limited to: antipsychotic drugs, antidepressants, benzodiazepines, prescription stimulants

Treatment and study plan

Personalized brain state-dependent single-pulse TMS

Device

Single-pulse TMS will be applied to the right hemisphere during brain activity patterns associated with strong and weak corticospinal tract activation. Single-pulse TMS will also be applied to the right hemisphere during random brain activity patterns.

Primary outcomes

  1. Motor-evoked Potential (MEP) Amplitudes

    Time frame: single session

    Peak-to-peak MEP amplitudes elicited by single transcranial magnetic stimulation (TMS) pulses delivered during personalized strong and weak CST states will be measured from the left first dorsal interosseous muscle. At the individual participant level, all MEP amplitudes will be normalized to the mean MEP amplitude observed in that participant. Mean normalized MEP amplitudes will be compared across CST states.

Secondary outcomes

  1. State-targeting Accuracy

    Time frame: single session

    An offline version of the real-time EEG analysis algorithm will be used to determine the brain state (i.e., strong or weak CST states, or neither) immediately preceding delivery of each single TMS pulse. The proportion of trials during which the online and offline versions of the real-time EEG analysis algorithm produce the same brain state prediction will be calculated per participant and used as a state-targeting accuracy metric. State-targeting accuracy metrics will be compared to the theoretical chance level (0.5).

Sponsors and collaborators

Lead sponsor

University of Texas at Austin

Other

Collaborators

  • Emory University

Registry information

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Apr 15, 2024
Registry last updated
Apr 17, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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