The Impact of Traumatic Brain injury and Aggregate Comorbidities on Cognitive Functioning in a Marginally Housed Sample

Individuals living in marginal urban housing face numerous health risks that impair cognition and produce burden in these individuals that may differentially attenuate capacity to tolerate further brain insult. We investigated the effect of self-reported traumatic brain injury (TBI) on cognition in persons with differential levels of neurocognitive burden. Two hundred and twenty participants (age: 23-68; 170 M, 50 F), recruited from single-room occupancy hotels underwent neurocognitive testing. A statistically weighted neurocognitive burden index was created reflecting the aggregate extent to which non-TBI comorbidities (vascular health, mental health, substance use, viral infection, neurological illness) and demographics (age, education, premorbid IQ) were associated with overall cognition. This index was investigated for its moderating influence on the relationship between self-reported TBI history (loss of consciousness of 30 minutes or more) and neurocognition. Hierarchical linear regression revealed that the burden index accounted for 31.4% of the total variance in cognition (F(1, 212) = 97.052, p < .001). TBI itself did not account for additional variance in cognition; nor did burden moderate the effect of TBI. Self-reported TBI history, as defined in the present study, has minimal value in signifying cognitive dysfunction in multimorbid marginally housed individuals.