Table 1 Fields contained in our data extraction form

Study characteristics

Author

Title

Journal

Year of publication

Country of publication

Inclusion criteria

Exclusion criteria

Study design

Sample size [total and subgroups]

Control variables [if applicable]

Study quality [grade]

Population characteristics

Mean age of sample [total and subgroups]

Time post-injury [total and subgroups]

Sex (% male) [total and subgroups]

Years of education [total and subgroups]

Injury severity (GCS, PTA) [total and subgroups]

Mechanism of injury [total and subgroups]

Baseline characterization (e.g., IQ, fitness)

Time elapsed between injury and baseline [total and subgroups]

Time elapsed between baseline and follow-up [total and subgroups]

Outcomes—primary

Independent variables—correlates to neurodegeneration

Medical [including pre-injury medical conditions or post-injury co-morbidities]

Neuropsychiatric [including pre-injury or post-injury psychiatric symptoms or diagnoses, including substance use]

Activity-related [including therapy, leisure pursuits, academic/employment activities, social, physical, cognitive (e.g., reading) activities

Social and environmental variables [including current living and social circumstances]

Baseline imaging [imaging type, regions assessed, sequence parameters]—both whole-brain and regional changes in volume or white matter integrity will be assessed

Follow-up imaging [imaging type, regions assessed, sequence parameters]—both whole-brain and regional changes in volume or white matter integrity will be assessed

Outcomes—primary Dependent variables—measures of neurodegeneration