Background: Cognitive impairment is common in patients with traumatic brain injury (TBI) at all levels of severity. Such impairments may affect their ability to return to work and thus increase healthcare costs and the associated economic burdens. Both cognitive rehabilitation and stimulant medications are widely used to manage post-traumatic cognitive impairments; however, previous metaanalyses failed to demonstrate their beneficial effects on cognitive recovery in patients with TBI. Nurses, the first-line healthcare providers, should therefore seek and use an alternative approach for dealing with post-traumatic cognitive deficits.

Purpose: To assess the effects of low resolution tomography (LoRETA) Z -score neurofeedback (NF) and theta/beta NF in alleviating cognitive impairments in patients with TBI as well as the possible mechanism through which they provide this alleviation. We hypothesize that adults with TBI receiving LoRETA Z-score NF and theta/beta NF will experience the improvements in cognitive functions while participants in the control group will not.

Cognitive impairment is the most common and debilitating residual symptom of traumatic brain injury (TBI) at all levels of severity and the prevalence of cognitive impairments varies, depending on the severity of the head injury and the time since the injury. Such impairments substantially affect a person's ability to return to productive activity and health-related quality of life. Furthermore, disabilities related to cognitive impairments following TBI increase healthcare costs and economic burden. Memory, attention, and information processing speed are basic cognitive functions. Deficits in such functions subsequently exacerbate disturbances in more complex cognitive functions (e.g., executive function). Therefore, targeting basic cognitive functions is the first priority of clinical treatments for post-traumatic cognitive impairments.

Cognitive rehabilitation, a nonpharmacological intervention, is the first-line treatment for the management of cognitive impairments following TBI. However, the findings of previous reviews are still debated, with one metaanalysis supporting its beneficial effects on attention recovery and two metaanalyses denying the positive association between cognitive rehabilitation and cognitive recovery. Pharmacotherapies (e.g., methylphenidate) has been potentially used to accelerate cognitive recovery in patients with TBI. Nevertheless, recent systematic reviews failed to prove its effects on cognitive recovery. Moreover, adverse effects may contribute to the discontinuation of stimulant medication use.Taken together, current treatments are insufficient for managing post-traumatic cognitive impairments. Nurses, the first-line healthcare providers, should therefore seek and employ an alternative approach to deal with cognitive impairments following TBI.

Both abnormal network connectivity of the brain (e.g., low neural communication between different brain areas) and dysregulated electroencephalographs (EEGs, e.g., increases in alpha and theta, and decrease in beta) following brain damage have been strongly connected to deficits in memory, sustained attention, and information processing speed. Neurofeedback (NF) can target and alter dysregulated brain functioning by giving real-time feedback of EEG activity to patients. Existing literatures have shown that NF might improve attention performance after TBI. Nonetheless, the effects of NF on other cognitive functions, such as memory and speed of information processing, have not been ascertained. In addition, limited methodological features of previous studies, including single group, pre- and posttreatment study design, small number of participants, and inconsistent treatment protocols, restrict their generalizability and practicability. Most importantly, knowledge regarding cognitive improvements being concomitant with changes in EEGs and the long-term effects of NF on cognitive recovery following TBI is still lacking.

Inclusion Criteria:

• Patients aged between 20 to 65 years, with a diagnosis of TBI at least 3 months before enrollment(Chronic phase, with an initial Glasgow Coma Scale score of 3-15 (i.e., initially rated in the attention, memory, and information processing speed) by the participants or treating clinician, are able to communicate in Mandarin Chinese, and are able to complete cognitive tasks (having Rancho Los Amigos Scale score>9) will be eligible for inclusion in the study.

Exclusion Criteria:

• The exclusion criteria include premorbid diagnoses of seizures, sleep disorders, psychiatry diseases, substance abuse, and alcoholism. Individuals who are pregnant, in the menopausal transition, and with impairments in vision, hearing, or motor functions that are severe enough to preclude participation in the research will be excluded.