Background Communication among neurons generates electromagnetic fields (EMFs) that can be measured through a noninvasive, portable helmet equipped with 20 sensors. The EMF data reveal a variety of EMF patterns that have yet to be elucidated. Understanding a propagated frequency from the brain and its subunits can assist with diagnosing the brain and its subunits' function and treatment. Here, the authors provide an interpretation of the EMF patterns with an emphasis on frequency. Methods From January 2025 to February 2025, a prospective clinical study was conducted to enroll patients greater than 18 years old diagnosed with atraumatic and traumatic brain injury whose EMFs, which were collected using a helmet equipped with 20 sensors, were obtained within 24 hours of presentation. EMF data were collected using DAQami software (DATAQ Instruments Inc., Akron, Ohio, United States) and analyzed using fast Fourier transformation with Igor Pro 8 software (WaveMetrics Inc., Lake Oswego, Oregon, United States). Based on each patient's clinical presentations and/or radiographic findings, the sensors of interest, their opposing sensors, and frequencies of interest (FOIs) were selected. Results A total of 10 patients were enrolled with a mean age of 47.1 years. Mechanisms of injury included spontaneous hypertensive intracranial hemorrhage (one patient) and head trauma after a motor vehicle collision, dirt bike accident, or ground-level fall (nine patients). Radiographic findings included spontaneous basal ganglia hemorrhage (one patient), isolated traumatic subdural hematoma (one patient), traumatic subarachnoid hemorrhage (one patient), and no intracranial abnormalities (seven patients). The following targeted FOIs were found: 5.2 Hz, 7.3 Hz, 7.6 Hz, 7.7 Hz, 7.9 Hz, 8.3 Hz, 8.6 Hz, 8.7 Hz, 9.5 Hz, and 10.4 Hz. Conclusions EMF of the human brain reveals changes in neuronal activities in atraumatic and traumatic brain injury patients. This information allows for the localization of sites of brain injuries and the selection of frequencies that can be used for understanding the EMF frequency and function on the macroscopic level as well as at the cellular level. This specific information can then be utilized for stimulation to modulate the changes in neuronal, circuit, and brain function activities. Our frequency selection technique enables more precise, tailored, and potentially more effective treatment aiming to restore EMF activity.