Patients evaluated at Penn Presbyterian Medical Center for traumatic brain injury (TBI), who sign the informed consent, will undergo assessment of electrophysiologic potentials evoked by transcranial magnetic stimulation (TMS), using the Delphi-MD device (QuantalX Neuroscience Ltd., Saba Israel).

Inclusion Criteria for Traumatic Brain Injury (Acute, Subacute, Chronic) group:

1. Age 18 years and older

2. Evidence of mechanical energy impacting the head or inertial forces affecting the head

3. Either (A) or (B):

   1. Trauma-related abnormality on CT scan on admission
   2. If CT normal, documented/verified TBI based on evidence of either loss of consciousness, post-traumatic amnesia, confusion, or post-traumatic symptoms.

Exclusion Criteria for Traumatic Brain Injury (Acute, Subacute, Chronic) group:

1. History of disabling pre-existing neurologic disease (Such as epilepsy, brain tumors, meningitis, cerebral palsy, encephalitis, brain abscesses, vascular malformations, cerebrovascular disease, Alzheimer's disease, multiple sclerosis, or HIV-encephalitis)
2. History of premorbid disabling condition that interfere with outcome assessments
3. Bilaterally absent pupillary responses
4. Penetrating traumatic brain injury
5. Prisoners or patients in police custody
6. Pregnancy
7. Subjects with magnetic-sensitive devices implanted in their head or within 12 in. (30 cm) of the coil/probe (examples: cochlear implants, deep brain stimulators, vagus nerve stimulators, other implanted electrodes/stimulators, aneurysm clips or coils, stents and bullet fragments).

Inclusion Criteria for Healthy Control group:

1. Age 18 years and older
2. No history of TBI in the past 12 months

Exclusion Criteria for Healthy Control group:

1. History of disabling pre-existing neurologic disease (Such as epilepsy, brain tumors, meningitis, cerebral palsy, encephalitis, brain abscesses, vascular malformations, cerebrovascular disease, Alzheimer's disease, multiple sclerosis, or HIV-encephalitis)
2. History of premorbid disabling condition that interfere with outcome assessments
3. Prisoners or patients in police custody
4. Pregnancy
5. Subjects with magnetic-sensitive devices implanted in their head or within 12 in. (30 cm) of the coil/probe (examples: cochlear implants, deep brain stimulators, vagus nerve stimulators, other implanted electrodes/stimulators, aneurysm clips or coils, stents and bullet fragments).

We will enroll up to 145 patients with a traumatic brain injury diagnosis evaluated at University of Pennsylvania Health System over 5 years. We will also evaluate up to 70 uninjured healthy controls, matched by age and gender to TBI participants.