A-09 The Relationship Between Subjective Cognitive Complaints, Depression, and Executive Functioning in mTBI Veterans

Objective

Among individuals with mild traumatic brain injury (mTBI), those with depression report greater subjective cognitive complaints than those without depression. In mTBI patients with general cognitive complaints, depression may account for poor performance on objective neuropsychological measures. This study seeks to expand this research by examining depression, subjective executive functioning (EF) complaints, and objective EF performance in Veterans with mTBI.

Method

Fifty-seven Veterans with deployment-related mTBI (12% female; age M = 42.0, SD = 13.6; years education M = 15.0, SD = 1.8) with (n = 29) or without (n = 28) a chart diagnosis of depression. Participants were administered the Behavioral Rating Inventory of Executive Functioning (BRIEF) and objective neuropsychological measures of working memory (i.e., Weschler Adult Intelligence Scale-IV Working Memory Index) and aspects of EF (i.e., Trail Making Test B and Delis-Kaplan Executive Functioning System (D-KEFS) subtests).

Results

Principal component analysis identified similar domains of EF to the BRIEF, including: task monitoring (Trail Making Test B, D-KEFS Letter Fluency, and D-KEFS Tower Test, eigenvalue = 1.93) and shifting (D-KEFS: Color-Word Interference Conditions 3 and 4, and Category Switching, eigenvalue = 1.24). Individuals with depression had greater subjective EF complaints in each BRIEF domain than non-depressed individuals (p’s ≤ .01). However, subjective complaints in these domains were not related to objective performance (r’s = −0.17,-0.19, p’s > .05). Moreover, depressed and non-depressed individuals performed similarly on all EF measures (p’s > .05).

Conclusions

mTBI Veterans with depression report more subjective EF complaints than those without depression. The lack of association between subjective complaints and objective EF performance suggests it is important to treat depression in mTBI patients to remedy perceived cognitive deficits.

Long-term non-invasive interrogation of human dorsal root ganglion neuronal cultures on an integrated microfluidic multielectrode array platform

Scientific studies in drug development and toxicology rely heavily on animal models, which often inaccurately predict the true response for human exposure. This may lead to unanticipated adverse effects or misidentified risks that result in, for example, drug candidate elimination. The utilization of human cells and tissues for in vitro physiological platforms has become a growing area of interest to bridge this gap and to more accurately predict human responses to drugs and toxins. The effects of new drugs and toxins on the peripheral nervous system are often investigated with neurons isolated from dorsal root ganglia (DRG), typically with one-time measurement techniques such as patch clamping. Here, we report the use of our multi-electrode array (MEA) platform for long-term noninvasive assessment of human DRG cell health and function. In this study, we acquired simultaneous optical and electrophysiological measurements from primary human DRG neurons upon chemical stimulation repeatedly through day in vitro (DIV) 23. Distinct chemical signatures were noted for the cellular responses evoked by each chemical stimulus. Additionally, the cell viability and function of the human DRG neurons were consistent through DIV 23. To the best of our knowledge, this is the first report on long-term measurements of the cell health and function of human DRG neurons on a MEA platform. Future generations will include higher electrode numbers in customized arrangements as well as integration with different tissue types on a single device. This platform will provide a valuable testing tool for both rodent and human cells, enabling a more comprehensive risk assessment for drug candidates and toxicants.