Brain stimulation in attention deficits after traumatic brain injury: a literature review and feasibility study

Abstract

Background After a traumatic brain injury, disturbances in the attentional processes have a direct negative effect on functional recovery and on return to complex activities. To date, there is no good attention remediation treatment available. The primary objective of this review and pilot study is to provide an overview of the research evidence and to evaluate the feasibility of implementing a tDCS protocol to improve attention disorders in patients with mild complicated to severe subacute TBI, hospitalized in an inpatient rehabilitation facility. Our secondary objective is to extract preliminary data and observational information on participants’ response to treatment. Methods Participants were recruited from a consecutive series of patients admitted to the TBI unit of a subspecialized regional rehabilitation center. They received a 20-min tDCS stimulation 3 times a week for 3 weeks. A neuropsychological evaluation was performed before and after the intervention. We collected participants’ sociodemographic and clinical characteristics as well as information about satisfaction, tolerability, and adverse effects. Results One hundred sixty-four patients were admitted between September 2018 and January 2020. One hundred fifty-eight were excluded, and 6 patients with presumed attentional deficits were enrolled. None completed the protocol as intended. No major side effects occurred. Conclusion Non-invasive brain neurostimulation is promising to enhance attention deficits in patients with TBI. Implementation of a tDCS protocol to fulfill this purpose in an intensive inpatient rehabilitation center has its limitations. We made recommendations to facilitate the implementation of similar projects in the future. Trial registration ISRCTN, ISRCTN55243064. Registered 14 October 2020—retrospectively registered.

A map of evidence using transcranial direct current stimulation (tDCS) to improve cognition in adults with traumatic brain injury (TBI)

“…Included studies, listed in Table 1 , represent research from Australia, Canada, Italy, South Korea, Poland, and the USA published between 2012 and 2021, all using anodal tDCS (A-tDCS) and targeting default mode attention and salience networks or networks connecting to these (Kang et al, 2012 ; Leśniak et al, 2014 ; Ulam et al, 2015 ; Sacco et al, 2016 ; O'Neil-Pirozzi et al, 2017 ; Li et al, 2019 ; Motes et al, 2020 ; Quinn et al, 2020 ; Boissonnault et al, 2021 ; Chiang et al, 2021 ; Eilam-Stock et al, 2021 ). The studies include people with mild to severe TBI, acute through chronic recovery phases, aged from 21 to 69 years and belonging to both male and female genders.…”

“…Eight studies targeted the dorsolateral prefrontal cortex (DLPFC), seven targeted the left (LDLPFC), and one targeted the lesioned DLPFC. Five studies targeting the LDLPFC (Kang et al, 2012 ; Leśniak et al, 2014 ; Ulam et al, 2015 ; O'Neil-Pirozzi et al, 2017 ; Boissonnault et al, 2021 ) used electrode placements A-F3, C-Fp2. A sixth study (Eilam-Stock et al, 2021 ) used A-F3 but differed by placing C-F4 corresponding to the right DLPFC.…”

“…Moreover, combined with existing treatments, tDCS improves functional outcomes. Though not approved for clinical use, tDCS is considered a minimal risk by the Food and Drug Administration for use in people with neurological impairments as a result of psychiatric symptoms such as depression (Sánchez-Kuhn et al, 2017 ; Boissonnault et al, 2021 ).…”

INCOG 2.0 Guidelines for Cognitive Rehabilitation Following Traumatic Brain Injury, Part II: Attention and Information Processing Speed

“…Most importantly, there is no evidence of generalization of gains from these interventions to everyday activities. Boissonnault et al 67 attempted to implement a tDCS protocol in the context of a rehabilitation center but had extremely low recruitment and retention, thus highlighting the limitations of application in a general rehabilitation setting.…”

“…Bogdanova et al 41 Dundon et al 51 Cicerone et al 50 Straudi Boissonault et al 67 Nousia et al 66 Neville et al 63 Rushby et al 61 Sacco et al 62 Ulam et al 60 (continues) Dorer e al 72 Chien et al 76 Dymowski et al 73 Huang et al 75 Jenkins et al 78 Johansson et al 30 Manktelow et al 71 Moreno-Lopez 70 Zhang and Wang 69 Attention no. 10 While amantadine may enhance arousal in patients in a minimally conscious state, it should not be used to enhance attentional functions following emergence from coma (updated from INCOG 2014, 28(p328) Attention 10).…”