Traumatic Brain Injury Characteristics Are Not Related to Neurocognitive Decline in Older Adults: A Nationwide Longitudinal Cohort Study

OBJECTIVE

Evaluate whether traumatic brain injury (TBI) characteristics, age of injury, or recency of injury predicts the course of neurocognitive decline and/or increases conversion rates to mild cognitive impairment (MCI) or dementia.

METHODS

Data were obtained from the National Alzheimer's Coordinating Center for participants 50-85 years old with 3-5 visits from 2015 to 2022, with or without TBI history (TBI+ = 508; TBI- = 2,382). Groups were stratified by self-reported TBI history (i.e., single TBI without loss of consciousness [LOC], single TBI with LOC, multiple TBI without LOC, and multiple TBI with LOC), age of most recent TBI, and recency of TBI. Mixed linear models compared neuropsychological composite trajectories (executive functioning/attention/speed, language, memory, and global), co-varying for age, gender, education, apolipoprotein E4 status, race/ethnicity, and baseline diagnosis (normal aging n = 1,720, MCI n = 749, or dementia n = 417). Logistic binary regression examined MCI/dementia conversion rates.

RESULTS

There was a slightly higher frequency of MCI/dementia in those with multiple TBIs (50% to 60% with and without LOC, compared to 39% with no TBI) at baseline, but longitudinal trajectories were similar. TBI history, age of injury, or recency of injury did not impact neurocognitive trajectories or conversion rates to MCI/dementia (all p's > .01).

CONCLUSIONS

TBI history, regardless of injury characteristics, age of injury, or recency of injury, did not worsen neurocognitive decline or MCI/dementia conversion. Additional longitudinal research in more diverse cohorts with a wider range of TBI severity is needed to evaluate the specific factors and possible mechanisms in which TBI may increase dementia risk.

Blood Markers in Relation to a History of Traumatic Brain Injury Across Stages of Cognitive Impairment in a Diverse Cohort

BACKGROUND

Traumatic brain injury (TBI) has been linked to multiple pathophysiological processes that could increase risk for Alzheimer's disease and related dementias (ADRD). However, the impact of prior TBI on blood biomarkers for ADRD remains unknown.

OBJECTIVE

Using cross-sectional data, we assessed whether a history of TBI influences serum biomarkers in a diverse cohort (approximately 50% Hispanic) with normal cognition, mild cognitive impairment, or dementia.

METHODS

Levels of glial fibrillary acidic protein (GFAP), neurofilament light (NFL), total tau (T-tau), and ubiquitin carboxy-terminal hydrolase-L1 (UCHL1) were measured for participants across the cognitive spectrum. Participants were categorized based on presence and absence of a history of TBI with loss of consciousness, and study samples were derived through case-control matching. Multivariable general linear models compared concentrations of biomarkers in relation to a history of TBI and smoothing splines modelled biomarkers non-linearly in the cognitively impaired groups as a function of time since symptom onset.

RESULTS

Each biomarker was higher across stages of cognitive impairment, characterized by clinical diagnosis and Mini-Mental State Examination performance, but these associations were not influenced by a history of TBI. However, modelling biomarkers in relation to duration of cognitive symptoms for ADRD showed differences by history of TBI, with only GFAP and UCHL1 being elevated.

CONCLUSIONS

Serum GFAP, NFL, T-tau, and UCHL1 were higher across stages of cognitive impairment in this diverse clinical cohort, regardless of TBI history, though longitudinal investigation of the timing, order, and trajectory of the biomarkers in relation to prior TBI is warranted.

Identification of Factors in Moderate-Severe TBI Related to a Functional Decline in Cognition Decades After Injury

OBJECTIVE

To investigate whether a functional decline in cognitive activities decades after moderate-to-severe traumatic brain injury (m-sTBI) might relate to injury features and/or lifetime health factors, some of which may emerge as consequences of the injury.

DESIGN

Secondary analysis of the TBI Model Systems National Database, a prospective, multi-center, longitudinal study of patients with m-sTBI.

SETTING

TBI Model Systems Centers.

PARTICIPANTS

Included were 732 participants rated on the cognitive subscale of the Functional Independence Measure (FIM Cognitive), a metric for everyday cognitive skills, across 3 time points out to 20 years (visits at 2-, 10-, and 20-year follow-ups; N=732).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

FIM Cognitive Scale. Injury characteristics such as timing and features pertaining to severity and health-related factors (eg, alcohol use, socioeconomic status) were examined to discriminate stable from declining participants on the FIM Cognitive Scale using logistic regression.

RESULTS

At 20 years post-injury, there was a low base rate of FIM Cognitive decline (11%, n=78), with most being stable or having meaningful improvement (89%, n=654). Older age at injury, longer duration of post-traumatic amnesia, and presence of repetitive seizures were significant predictors of FIM Cognitive decline in the final model (area under the curve=0.75), while multiple health-related factors that can represent independent co-morbidities or possible consequences of injury were not.

CONCLUSION(S)

The strongest contributors to reported functional decline in cognitive activities later-in-life were related to acute characteristics of m-sTBI and experiencing post-traumatic seizures. Future studies are needed integrating functional with performance-based cognitive assessments to affirm conclusions and identify the timeline and trajectory of cognitive decline.

History of traumatic brain injury does not alter course of neurocognitive decline in older adults with and without cognitive impairment

OBJECTIVE

Traumatic brain injury (TBI) history is associated with dementia risk, but it is unclear whether TBI history significantly hastens neurocognitive decline in older adults.

METHOD

Data were derived from the National Alzheimer's Coordinating Center (NACC) data set. Participants with a history of TBI (TBI +; n = 1,467) were matched to individuals without a history of TBI (TBI-; n = 1,467) based on age (50-97, M = 71.61, SD = 8.40), sex, education, race, ethnicity, cognitive diagnosis, functional decline, number of Apolipoprotein ε4 (APOE ε4) alleles, and number of annual visits (3-6). Mixed linear models were used to assess longitudinal neuropsychological test composite scores of executive functioning/attention/speed, language, and memory in TBI + and TBI- participants. Interactions between TBI and demographics, APOE ε4 status, and cognitive diagnosis were also examined.

RESULTS

Longitudinal neuropsychological functioning did not differ between TBI groups (p's > .001). There was a significant three-way interaction (age, TBI history, time) in language (F[20, 5750.1] = 3.133, p < .001) and memory performance (F[20, 6580.8] = 3.386, p < .001), but post hoc analyses revealed TBI history was not driving this relationship (all p's > .096). No significant interactions were observed between TBI history and sex, education, race/ethnicity, number of APOE ε4 alleles, or cognitive diagnosis (p's > .001).

CONCLUSIONS

Findings suggest TBI history, regardless of demographic factors, APOE ε4 status, or cognitive diagnosis, does not alter the course of neurocognitive functioning later-in-life in older adults with or without cognitive impairment. Future clinicopathological longitudinal studies that well-characterize head injuries and the associated clinical course are needed to help clarify the mechanism in which TBI may increase dementia risk. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A - 156 History of Mild Traumatic Brain Injury Is Not Associated with worse Neuropsychological Functioning in Amnestic Mild Cognitive Impairment

OBJECTIVE

The mechanisms for traumatic brain injury (TBI) being a risk factor for Alzheimer's disease is unclear, and whether mild TBI (mTBI) may relate to decreased neural circuit functioning in the prodromal phase is unknown. This study examined whether a history of mTBI was associated with lower functioning of neural circuits, measured with neuropsychological tasks, in amnestic Mild Cognitive Impairment (aMCI).

METHOD

Twenty older adults (MAge = 71 years; 70% Male; 90% White) with aMCI were recruited to complete a detailed TBI interview and were classified based on the presence (mTBI+ n = 13) or absence (mTBI- n = 7) of past mTBI. Most mTBI+ participants (n = 11) had multiple mTBIs, and on average were 32 years from last injury. A comprehensive neuropsychological assessment was administered, and composite T-scores were calculated for the domains of attention, executive functioning, memory, and language. One-tailed T-tests were conducted to compare the means between groups.

RESULTS

No statistically significant differences (p's = 0.06-0.09) were found between the groups in memory (mTBI+ M = 38.11; mTBI- M = 33.19), executive function (mTBI+ M = 48.79; mTBI- M = 43.09), language (mTBI+ M = 48.12; mTBI- M = 43.09), or attention (mTBI+ M = 40.54; mTBI- M = 35.57). Nonetheless, medium effect sizes were seen for the mTBI+ group performing better than the mTBI- group on all composite scores (Cohen's d = 0.45-0.66).

CONCLUSIONS

A history of mTBI was not associated with poorer neuropsychological performance in aMCI, often a prodromal stage of Alzheimer's disease. While concerns about later-in-life effects from multiple mTBIs is prevalent, repetitive mTBI may not be related to lower neural circuit functioning in aMCI, though further evaluation with larger samples is needed.

A - 133 Self-Reported Loss of Consciousness Predicts Executive Functions in Veterans with a History of Traumatic Brain Injury

OBJECTIVE

The long-term cognitive effects of traumatic brain injury (TBI) in military personnel remain unclear and need to be better understood. We assessed how cognitive performance was related to the remote history of TBI involving loss of consciousness (LOC) and blast injury (regardless of LOC) in veterans.

METHOD

Veterans (N = 101; age 42.8 ± 10.5 years; 10 Females) with a self-reported history of TBI and persistent cognitive symptoms were recruited. Effects of (1) the presence of LOC, (2) total number of TBIs with LOC (0, 1-2, >2), and (3) the presence of blast injury were examined on composite scores from tests of executive function (Trail-Making Test B, Color Word Interference), word retrieval (Boston Naming, Letter and Category Fluency), processing speed (Trail Making-A, Color Word Naming/Reading), and episodic memory (Rey-Auditory Verbal Learning Test-total learning and delayed recall), while controlling for age, sex, years of education, and total number of TBIs.

RESULTS

TBI with LOC was a significant predictor of executive function (p = 0.014) and processing speed (p = 0.014), with more episodes of LOC predicting lower functioning, but not of word retrieval or episodic memory (p > 0.1). Additionally, presence of a blast injury, regardless of LOC, did not predict differences in function on any of the composite measures.

CONCLUSIONS

Self-reported TBI history with LOC was associated with poorer executive function and processing speed. The findings further characterize the relationship between TBI history and long-term cognitive sequelae in veterans, particularly suggesting LOC can affect neural systems underlying executive function and processing speed.

A - 22 Preliminary Outcomes on Depression Symptoms in a Randomized Controlled Trial of High-Definition Transcranial Direct Current Stimulation in Alzheimer's Dementia

OBJECTIVE

New treatments to manage emotional and cognitive symptoms of Alzheimer's Dementia (ad) are needed. High-definition transcranial direct current stimulation (HD-tDCS) is a non-invasive neuromodulation technology with potential as a new treatment for improving neuropsychiatric symptoms. The dorsal anterior cingulate cortex (dACC) is a region found to play an important role in emotional processes and is vulnerable to degeneration in ad. As such, we conducted a pilot study investigating the effect of HD-tDCS applied over the dACC on depression symptoms in ad patients.

METHOD

Ten participants (M age = 71.50, SD = 9.80) with clinically diagnosed mild-to-moderate ad were randomized to receive sham (0 milliamps [mA]; n = 2), 1 mA (n = 5), or 2 mA (n = 3) HD-tDCS for ten daily 20-minute sessions across two weeks. The Beck Depression Inventory-2 (BDI-2) was administered before and after ten treatments. A one-tailed analysis of covariance (ANCOVA) was conducted to examine differences in post-treatment scores between HD-tDCS groups, adjusting for pre-treatment scores.

RESULTS

Baseline BDI-2 scores were similar for the groups receiving 1 mA (M = 7.00; SD = 3.10), 2 mA (M = 4.70; SD = 8.10), and sham (M = 9.00; SD = 7.10) Statistically significant differences were found between groups on depression scores after HD-tDCS, F(2) = 3.55, p = 0.048, ηp2 = 0.54), driven by the depression scores in the 1 mA group being lower than the sham group.

CONCLUSIONS

Our pilot results suggest that HD-tDCS may be associated with a reduction in depression symptoms in ad, though determining the minimum clinically important difference for a decrease needs further evaluation. Future research having larger samples with ad and long-term follow up is also warranted to examine clinical efficacy.

A - 17 Preliminary Neuropsychological Outcomes in a Randomized Controlled Trial of High-Definition Transcranial Direct Current Stimulation in Alzheimer's Clinical Syndrome

OBJECTIVE

The Alzheimer's Clinical Syndrome (ACS) is marked by global cognitive decline, and neural circuit dysfunction involving the dorsal anterior cingulate cortex (dACC) has been associated with some of the episodic memory and non-memory deficits in ACS. High-definition transcranial direct current stimulation (HD-tDCS) is a promising noninvasive treatment to lessen cognitive deficits in ACS, and this preliminary double-blinded trial examined whether HD-tDCS targeting the dACC could improve cognitive performance in ACS.

METHODS

Ten patients diagnosed with ACS (M age = 71.500; SD = 9.755) were randomized to receive sham (n = 2), 1 mA (n = 5), or 2 mA (n = 3) multi-electrode (4 cathodes x 1 anode) HD-tDCS for 10 daily sessions. Episodic memory, language, attention, and executive function measures were administered pre- and immediately post-treatment, and composite memory and non-memory scores were calculated. Paired samples t-tests examined significant differences (p < 0.05) between pre-treatment and post-treatment scores for each HD-tDCS group.

RESULTS

For all three HD-tDCS groups, there were no significant improvements between pre-treatment and post-treatment scores for memory or non-memory abilities (p's > 0.05).

CONCLUSION

This preliminary study showed that HD-tDCS applied over the dACC was unassociated with cognitive improvement in ACS. Future research with a larger sample will be needed to inform if this configuration of HD-tDCS could ameliorate cognitive deficits in ACS. Moreover, evaluation of HD-tDCS applied over other brain regions may yield additional insights, and a critical step will be to identify whether any clinical characteristics such as disease stage may influence the response to stimulation in ACS.

A - 42 Neuropsychological Improvement in Amnestic Mild Cognitive Impairment Following Noninvasive Transcranial Electrical Stimulation: a Case Report

OBJECTIVE

Amnestic Mild Cognitive Impairment (aMCI) is often a prodromal stage for Alzheimer's disease, and the few treatments available have limited efficacy in lessening the neuropsychological deficits. Transcranial direct current stimulation (tDCS) is a noninvasive electrical stimulation method with therapeutic potential found in aMCI, but high-definition tDCS (HD-tDCS) is a recent advancement allowing for improved targeting in stimulation and possibly prolonged treatment effects. We present a case report that investigates HD-tDCS-induced neuropsychological changes in aMCI.

METHOD

A 78-year-old male with aMCI received 10 HD-tDCS sessions at 1 mA for 20 minutes targeting the dorsal anterior cingulate cortex. He was stable on rivastigmine throughout the trial. Eight neuropsychological tests assessing episodic memory (verbal and visual), attention, executive functioning, and language were completed at baseline, after the 10th session and 3-months later. A change of +/- 10 T-score points from baseline was considered a clinically meaningful difference.

RESULTS

Significant improvements were observed immediately after HD-tDCS on 4/8 tests, including the Brief Visuospatial Memory Test-Revised (BVMT-R; immediate recall +14; delayed recall +24), semantic fluency (Animals +17), Trail Making Test B (+14), and Stroop Color and Word Interference Trial (+21). At the 3-month follow-up, only the BVMT-R immediate recall remained higher (+16), while the rest were similar to baseline scores.

CONCLUSIONS

Clinically meaningful improvement in neuropsychological functioning was seen following HD-tDCS in this patient with aMCI. However, nearly all the enhancements were diminished 3-months later, returning to baseline. A randomized sham-controlled trial is warranted to confirm the therapeutic effects of HD- tDCS and examine how long effects may persist.

A - 12 Traumatic Brain Injury Characteristics Are Not Related to Neurocognitive Decline in Older Adults: a Nationwide Longitudinal Cohort Study

OBJECTIVE

Evaluate if traumatic brain injury (TBI) characteristics, age of injury, or recency of injury is related to course of neurocognitive decline in aging and/or increases conversion rates to mild cognitive impairment (MCI) or all-cause dementia later in life.

METHODS

Data were obtained from the National Alzheimer's Coordinating Center for participants 50-85 years old with 3 to 5 visits from 2015-2022. Groups were stratified by: 1) self-reported TBI history (No TBI [n = 2382], Single TBI without loss of consciousness [LOC; n = 102], Single TBI w/LOC [n = 228], Multiple TBI without LOC [n = 36], and Multiple TBI w/LOC [n = 115]), 2) age of most recent TBI (No TBI [n = 2382], TBI = 65 years old [n = 76]), and 3) recency of TBI (no TBI [n = 2382], 15 years ago [n = 301]). Mixed linear models compared normed neuropsychological composite trajectories (executive functioning/attention/speed, language, memory, and overall), co-varying for age, gender, education, apolipoprotein E4 status, and baseline diagnosis (normal aging n = 1720, MCI n = 749, or dementia n = 417). Logistic binary regression examined MCI/dementia conversion rates.

RESULTS

Longitudinal neurocognitive trajectories in composite measures were similar among TBI groups (example figure below). Specific TBI history, age of injury, or recency of injury did not impact neurocognitive trajectories or conversion rates to MCI or dementia (all p's > 0.01).

CONCLUSIONS

TBI history, regardless of injury characteristics, age, or recency, did not worsen neurocognitive decline or MCI/dementia conversion. The mechanism and factors that increase dementia risk after TBI are unclear. Additional longitudinal research in carefully designed longitudinal cohorts is needed.

Early vs. delayed evaluation and persisting concussion symptoms during recovery in adults

Objective: Persisting concussion symptoms may adversely affect return to work and functioning in daily activities. This study compared adults who were initially evaluated < 30 days versus those evaluated ≥ 30 days following a concussion at a specialty concussion clinic to determine if delayed initial evaluation is associated with persisting symptoms during recovery. Method: Participants (N = 205) 18 years of age and older who sustained a concussion and presented to a North Texas Concussion Registry (ConTex) clinic were evaluated at two time points: initial clinical visit and three-month follow-up. Participants provided medical history, injury related information, and completed the Sport Concussion Assessment Tool-5 Symptom Evaluation, Generalized Anxiety Disorder 7-item scale (GAD-7), and Patient Health Questionnaire (PHQ-8). Participants were divided into two groups: early and delayed evaluation (±30 days post injury). Results: Number and severity of concussion symptoms were similar between both groups at their initial clinical visit. However, linear regression models showed that a delayed clinical evaluation was associated with a greater number and severity of concussion symptoms along with greater aggravation of symptoms from physical and cognitive activity at three-month follow-up. Conclusions: Individuals who sought care at specialty concussion clinics regardless of previous care 30 or more days following their injury reported more serious persisting concussion symptoms at three month follow-up than those who sought care sooner. Education to improve adults' recognition of concussions when they occur and obtaining earlier clinical evaluation may represent important opportunities in promoting better recovery and reducing persisting concussion symptoms.

No association between age beginning tackle football, or years played and neurocognitive performance later-in-life among older National Football League retirees

OBJECTIVE

In a retrospective cohort, we evaluated whether age beginning tackle football (ABTF) and more total years of playing football (TYPF) were associated with worse later-in-life neuropsychological change among older retired National Football League (NFL) players.

METHOD

Participants were 19 older NFL retirees aged 54-79, including 12 who returned for follow-up evaluation 15-51 months later. Mixed-linear models evaluated the association between ABTF/TYFP and baseline neuropsychological composite scores (executive functioning/attention/speed, language, memory), and neuropsychological composites over time.

RESULTS

ABTF and TYPF were not significantly associated with neuropsychological composites at baseline or over time (all p's > .05). There were no significant differences in neuropsychological performance between those ABTF <12 and ≥ 12 years old (all p's ≥ .475) or between those with TYPF <19 or ≥ 19 years played (median split; all p's ≥ .208).

CONCLUSIONS

Preliminary findings suggest that ABTF and TYPF does not worsen neurocognitive decline later-in-life among older NFL retirees.

Effect of traumatic brain injury on mild behavioral impairment domains prior to all-cause dementia diagnosis and throughout disease progression

Introduction

Traumatic brain injury (TBI) may alter dementia progression, although co-occurring neuropsychiatric symptoms (NPS) have received less attention. Originally designed to evaluate behavioral disruption prior to dementia diagnosis, the mild behavioral impairment (MBI) construct relates NPS to underlying neural circuit disruptions, with probable relevance across the progression of neurodegenerative disease. Therefore, the MBI construct may represent a valuable tool to identify and evaluate related NPS both preceding diagnosis of all-cause dementia throughout the progression of disease, representing an important area of inquiry regarding TBI and dementia. This investigation sought to evaluate the effect of TBI on NPS related by the MBI construct in participants progressing from normal cognitive status to all-cause dementia.

Methods

Using National Alzheimer's Coordinating Center data, individuals progressing from normal cognition to all-cause dementia (clinician diagnosed) over 7.6 ± 3.0 years were studied to estimate prevalence of MBI domains in 124 participants with prior TBI history (57 with loss of consciousness [LOC] <5 minutes, 22 with LOC >5 min, 45 unknown severity) compared to 822 without. MBI domain prevalence was evaluated (1) prior to dementia onset (including only time points preceding time at dementia diagnosis, as per MBI's original definition) and (2) throughout dementia progression (evaluating all available time points, including both before and after dementia diagnosis).

Results

More severe TBI (LOC >5 minutes) was associated with the social inappropriateness MBI domain (adjusted odds ratio = 4.034; P = 0.024) prior to dementia onset, and the abnormal perception/thought content domain looking across dementia progression (adjusted hazard ratio [HR_adj] = 3.703; P = 0.005). TBI (all severities) was associated with the decreased motivation domain looking throughout dementia progression (HR_adj. = 1.546; P = 0.014).

Discussion

TBI history is associated with particular MBI profiles prior to onset and throughout progression of dementia. Understanding TBI's impact on inter-related NPS may help elucidate underlying neuropathology with implications for surveillance, detection, and treatment of behavioral concerns in aging TBI survivors.

Highlights

The mild behavioral impairment (MBI) construct links related neuropsychiatric symptoms (NPS) by probable underlying neural network dysfunction.Traumatic brain injury (TBI) with loss of consciousness (LOC) > 5 minutes was associated with pre-dementia social inappropriateness.TBI was associated with decreased motivation looking across dementia progression.TBI with LOC > 5 minutes was associated with abnormal perception/thought content.The MBI construct may be useful for examining related NPS across dementia progression.

Neurocognitive outcomes of older National Football League retirees

OBJECTIVE

Determine if head-injury exposure relates to later-in-life cognitive decline in older National Football League (NFL) retirees.

METHOD

NFL retirees (aged 50+) with or without cognitive impairment underwent baseline (n = 53) and follow-up (n = 29; 13-59 months later) neuropsychological evaluations. Cognitively normal (CN) retirees (n = 26) were age- and education-matched to healthy controls (n = 26). Cognitively impaired (CI) retirees with mild cognitive impairment or dementia (n = 27) were matched to a clinical sample (CS) by age, sex, education, and diagnosis (n = 83). ANOVAs compared neuropsychological composites at baseline and over time between retirees and their matched groups. Regression models evaluated whether concussions, concussions with loss of consciousness (LOC), or games played predicted neuropsychological functioning.

RESULTS

At baseline, CN retirees had slightly worse memory than controls (M_{CN retirees} = 50.69, SE_{CN retirees} = 1.320; M_{Healthy controls} = 57.08, SE_{Healthy controls} = 1.345; p = 0.005). No other group diferences were observed, and head-injury exposure did not predict neurocognitive performance at baseline or over time.

CONCLUSIONS

Head-injury exposure was not associated with later-in-life cognition, regardless of cognitive diagnosis. Some retirees may exhibit lower memory scores compared to age-matched peers, though this is of unclear clinical significance.

Southwestern Assessment of Processing Speed (SWAPS): A new brief test with demographically-corrected norms in an ethnically and educationally diverse population

Objective. Neuropsychological measures of processing speed have long been used as sensitive indices of cognitive functioning. Most of these commonly used tests are proprietary, and there is a need for brief, freely available tools that can be used in diverse clinical and research settings. The Southwestern Assessment of Processing Speed (SWAPS) is a 60-second digit-symbol transcription task developed as a brief alternative to commercially available coding tests. Demographically-corrected normative data are presented along with reliability and sensitivity/specificity values in older adults with and without cognitive impairment.Method. SWAPS data from 915 healthy aging individuals (NC) and 858 subjects with clinical diagnoses of mild cognitive impairment (MCI; n = 430) and Alzheimer's disease clinical syndrome (ADCS; n = 428) were obtained from the Texas Alzheimer's Research and Care Consortium (TARCC). TARCC participants represent ethnically and educationally diverse community-dwelling individuals age 50+.Results. SWAPS scores showed the expected associations with age, sex, and education, and the interaction between age and education were significant predictors of SWAPS scores. Test-retest reliability in NC was good, and the SWAPS distinguished impaired and non-impaired groups with adequate to excellent sensitivity and specificity for the primary analyses, with optimal cut-off points provided. Raw score- to uncorrected normalized T-scores and demographically-corrected SWAPS T-scores using regression-based norms are presented along with scoring programs for the calculation of each.Conclusions. The SWAPS is a brief, free, easily administered test with demographically-corrected regression-based norms and promising utility for detection of cognitive impairment and efficient assessment of processing speed.

A-4 Executive Functioning Is an Important Predictor of Life Expectancy in Those with All-Cause Dementia

Objective: Neuropsychiatric, functional, motor, and demographic factors have been associated with life expectancy (LE) in those with dementia. Recent findings suggested cognition (assessed by the Mini-Mental State Exam [MMSE]) to be the strongest predictor of LE in Alzheimer’s disease (ad; Schaffert et al., 2022). We evaluated if more detailed neuropsychological scores predict LE in a larger sample of individuals with all-cause dementia.

Method: Participants were 4090 deceased individuals (Mage = 74.5, Meducation = 14.8, Male = 44%, White = 90%, Non-Hispanic = 96%) with all-cause dementia (at visit 1, ad = 78%) from the National Alzheimer’s Coordinating Center. Three index scores [executive function/speed/attention (EFAS), language, memory] were calculated from NACC’s neuropsychological batteries. Variables (from visit 1) were entered into a forward regression model (p &lt; 0.001 as point-of-entry) to predict days of LE, and included: age, gender, race (white/non-white), ethnicity (Hispanic/Non-Hispanic), diagnosis (ad/non-ad), abnormal neurological exam (yes/no), Functional Activities Questionnaire (FAQ, total score), Neuropsychiatric Inventory Questionnaire (NPI-Q, total score), MMSE, and EFAS, language, and memory composite Z-scores.

Results: Performance on the EFAS composite explained the most variance in LE (R2 = 0.065), followed by age (R2 = 0.044), diagnosis (R2 = 0.023), FAQ (R2 = 0.016), gender (R2 = 0.012), abnormal neurological exam (R2 = 0.006), NPI-Q (R2 = 0.004), language abilities (R2 = 0.003), and Hispanic ethnicity (R2 = 0.003). Plus/minus one Z-score on the EFAS composite predicted 158 days of LE, and each year of age predicted 27 days of LE.

Conclusions: EFAS performance and age explained &gt;10% of LE variance. The MMSE failed to predict LE in this model that included more detailed neuropsychological data. EFAS impairment may be a more important predictor of LE compared to other neurocognitive domains and cognitive screeners.

A-223 Preliminary Investigation of Convergent Validity and Utility of the Texas Postconcussion Symptom Inventory

Objective: The Texas Postconcussion Symptom Inventory (TPSI) is a novel, 66-item, self-report instrument with empirically-derived indices that provides a summed total score to assess recovery following concussion. This study evaluated convergent validity of the TPSI with the Sport Concussion Assessment Tool Post-Concussion Symptom Scale (PCSS), and examined differences in symptom scores between recovered and non-recovered adults to assess its utility in measuring post-concussion symptoms.

Method: Adults (N=37; Mage=41.6; Female=59.5%; White=89.2%) diagnosed with concussion were recruited from a larger concussion study (ConTex) to complete the TPSI and PCSS three months after initial clinical evaluation. Convergent validity was assessed using nonparametric correlation analyses between total symptom severity scores on the PCSS and TPSI for all subjects. Independent sample t-tests examined whether the TPSI total symptom score differed between the adults reporting lingering symptoms (N=19) and those who had recovered (N=18).

Results: Total TPSI symptom score strongly correlated with the PCSS total symptom score (ρ = .867; p&lt;.001). Non-recovered adults (MTPSI = 55.61; SDTPSI = 26.38) reported significantly higher symptom scores than recovered adults (MTPSI = 34.64; SDTPSI = 22.69) on the TPSI t(35) = 2.59, p = .014, d = 0.85, 95% CI, [4.53, 37.32].

Conclusion(s): The TPSI demonstrated strong convergent validity with a common clinical postconcussion symptom instrument and identified significant differences in symptom reporting between recovered and non-recovered adults after a concussion. Future research will build upon these preliminary results and determine the utility of the TPSI in the acute stage following concussion as well as in tracking recovery.

Predictors of Life Expectancy in Autopsy-Confirmed Alzheimer's Disease

BACKGROUND

Life expectancy (LE) following Alzheimer's disease (AD) is highly variable. The literature to date is limited by smaller sample sizes and clinical diagnoses.

OBJECTIVE

No study to date has evaluated predictors of AD LE in a retrospective large autopsy-confirmed sample, which was the primary objective of this study.

METHODS

Participants (≥50 years old) clinically and neuropathologically diagnosed with AD were evaluated using National Alzheimer's Coordinating Center (N = 1,401) data. Analyses focused on 21 demographic, medical, neuropsychiatric, neurological, functional, and global cognitive predictors of LE at AD dementia diagnosis. These 21 predictors were evaluated in univariate analyses. Variables found to be significant were then entered into a forward multiple regression. LE was defined as months between AD diagnosis and death.

RESULTS

Fourteen predictors were significant in univariate analyses and entered into the regression. Seven predictors explained 27% of LE variance in 764 total participants. Mini-Mental State Examination (MMSE) score was the strongest predictor of LE, followed by sex, age, race/ethnicity, neuropsychiatric symptoms, abnormal neurological exam results, and functional impairment ratings. Post-hoc analyses revealed correlations of LE were strongest with MMSE ≤12.

CONCLUSION

Global cognitive functioning was the strongest predictor of LE following diagnosis, and AD patients with severe impairment had the shortest LE. AD patients who are older, male, white, and have more motor symptoms, functional impairment, and neuropsychiatric symptoms were also more likely have shorter LE. While this model cannot provide individual prognoses, additional studies may focus on these variables to enhance predictions of LE in patients with AD.

Mild Traumatic Brain Injury Is Related to Elevated Cerebrospinal Fluid Tau in Alzheimer's Disease Dementia

Few studies have examined an association between mild traumatic brain injury (mTBI) and Alzheimer's disease (AD). For this reason, we compared an AD dementia group with an mTBI history (n = 10) to a matched AD control group (n = 20) on measures of cognitive function, cerebral glucose metabolism, and markers of amyloid and tau deposition. Only a trend and medium-to-large effect size for higher phosphorylated and total tau was identified for the mTBI group. A history of mTBI may be associated with greater tau in AD, indicating a potential pathway for increasing risk for AD, though further evaluation with larger samples is needed.

Resilience and recovery from sports related concussion in adolescents and young adults

INTRODUCTION

Recovery and return to play are important milestones for athletes who sustain sport-related concussions (SRC). Several factors have been shown to influence resolution of post-concussion related symptoms (PCS), but resilience, a trait that reflects the ability to overcome adversity, is another factor that may influence recovery. The aim of this study was to determine the relationship of resilience with resolution of symptoms during recovery in adolescents and young adults following SRC.

METHOD

This prospective study is part of the North Texas Concussion Registry (ConTex). Subjects (N = 332) aged 13 to 25 years who sustained a SRC within 10 days of presenting to clinic were evaluated at two time points: initial clinical visit and three-month follow-up. Resilience was measured by the self-report Brief Resilience Survey (BRS) and PCS by the Sport Concussion Assessment Tool-5 Symptom Evaluation Post-Concussion Symptom Scale (PCSS). Recovery was determined by self-reported return to sports/physical activity and percent back to normal.

RESULTS

Repeated measures ANCOVA and linear regression models showed that lower resilience ratings at initial visit were associated with a greater number and severity of PCSS symptoms along with higher levels of anxiety and depression symptoms during recovery from SRC. At three months, subjects with lower initial resilience ratings were less likely to report feeling back to normal and had greater aggravation of symptoms from physical and cognitive activity even when they had returned to sports/physical activity.

CONCLUSIONS

Lower resilience was associated with greater symptoms and delayed recovery from SRC. Results suggest that resilience may be another important factor to address in recovery from SRC. Future research is needed to examine the extent to which resilience measured after SRC reflects pre-injury characteristics and to better inform the development of interventions to promote resilience during recovery.

A-196 The Texas Postconcussion Symptom Inventory (TPSI): An Exploratory Factor Analysis and Reliability Analysis

Objective

Self-report scales are commonly used to evaluate non-specific symptoms following concussion. While several scales have been developed, few were created using a systematic process and most contain several ambiguous items that may be misinterpreted. To address this, a new theoretically-based, multidimensional measure was designed to assess Cognitive, Neuropsychiatric, and Somatic symptoms associated with concussion. This study used sophisticated psychometric techniques to develop the Texas Postconcussion Symptom Inventory (TPSI) and establish initial reliability and validity.

Method

Because concussion symptoms are non-specific, a pool of 76 potential items was developed and administered to a diverse clinical sample (N = 350) that included patients with concussion, epilepsy, and dementia. Polychoric correlations were utilized to remove items based on poor fit/multicollinearity and an exploratory factor analysis (EFA) with an Oblimin rotation was used to determine factor structure.

Results

A three-factor model best fit the data, and represented Cognitive, Neuropsychiatric, and Somatic domains as designed. Ten items were discarded, resulting in a total of 66 items. The model explained 48.5% of the total variance and contained adequate sampling (Kaiser-Meyer-Olkin measure =0.92) and sufficient item correlations (Bartlett’s Test of Sphericity, p &lt; 0.05) for EFA. All three factor structures displayed high internal consistency (Cronbach’s α &gt; 0.88).

Conclusions

The TPSI is a brief, multidimensional measure with evidence of strong internal consistency and reliability as well as distinct Cognitive, Neuropsychiatric, and Somatic symptoms associated with concussion. Future research will investigate its convergent and divergent validity in concussion as compared to existing popular symptom measures.

A-3 History of Traumatic Brain Injury and the Course of Neuropsychiatric Symptoms among those with Autopsy-Confirmed Alzheimer’s Disease

Objective

We explored the course of neuropsychiatric symptoms (NPS) in autopsy-confirmed Alzheimer’s disease (ad) subjects with and without a history of TBI (TBI+ vs. TBI-), expecting that TBI history may be associated with NPS severity over time.

Method

Data from 1532 individuals (age 50+) with autopsy-confirmed ad were obtained from the National Alzheimer’s Coordinating Center (Mean visits = 3.69). Those with other tau pathology and significant Lewy pathology were removed. Neuropsychiatric Inventory Questionnaire (NPI-Q) and the 15-item Geriatric Depression Scale (GDS) scores were used to examine NPS. Multilevel zero-inflated binomial regression models assessed if NPS severity differed between TBI+ (N = 154) and TBI- (N = 1378) groups over time. Covariates included: years from baseline visit, demographics, MMSE, Functional Activities Questionnaire score, and psychotropic treatment.

Results

The groups did not differ at baseline in NPI-Q (p = 0.36) or GDS (p = 0.07) scores. NPI-Q scores mildly decreased in the TBI+ group (trend = −0.03), whereas the TBI- group remained stable over time (trend = 0.001), 95% CI for the trend [0.01, 0.07]. GDS scores increased more rapidly in the TBI+ group (trend = 0.08) than the TBI- group (trend = 0.02), 95% CI for the trend [0.02, 0.10].

Conclusions

This preliminary study suggests that NPS course in ad may differ depending on TBI history, though effect sizes were small. Over the course of ad, individuals with a history of TBI may experience less NPS overall (as measured by NPI-Q scores) but may experience marginally more depressive symptoms (as measured by GDS scores). Future investigations evaluating the relationship between TBI and the course of neurodegenerative disease are needed.

A-193 Effects of Sex on Concussion-Related Symptom Reporting in a Diverse Adult Clinical Sample Using the Texas Postconcussion Symptom Inventory

Objective

Concussion symptoms are non-specific and various symptom inventories are influenced by sex, even in the absence of injury. The Texas Postconcussion Symptom Inventory (TPSI) is a new 66-item concussion-related symptom measure with three empirically-derived indices (Cognitive, Neuropsychiatric, and Somatic). We evaluated if symptom reporting on the TPSI related to sex in a large, mixed clinical sample.

Methods

A diverse clinical sample (N = 319, ages 17–92, M = 48.75), including patients with seizure disorders, dementias, and head injuries, completed the TPSI. Symptom reporting profiles between females (55%) and males (45%) were compared using profile analysis with age as a covariate.

Results

Although females (M = 20.62, 95% CI [18.91, 22.26]) and males (M = 19.14, 95% CI [17.32, 21.04]) endorsed higher scores on the Cognitive index (Possible Range = 0–52), no significant differences on symptom reporting patterns were seen between the groups on the Cognitive (p = 0.24) or Neuropsychiatric (p = 0.56) Indices. However, a significant difference was found on the Somatic index (Possible Range = 0–34), with females (M = 13.06, 95% CI [11.99, 13.94]) reporting higher scores [t(318) = 2.78, p &lt; 0.01, partial η2 = 0.02] than males (M = 10.98, 95% CI [10.01, 12.17]).

Conclusions

In this preliminary study, results indicated sex differences in reporting concussion-associated symptoms on the TPSI across a variety of clinical conditions. Similar to prior studies, females reported more somatic symptoms yet were similar in their reports of Cognitive and Neuropsychiatric symptoms. Because baseline data is rarely available when evaluating concussions in clinical settings, future research aims are to develop normative data stratified by sex and investigate the utility of the TPSI within a concussion cohort.

A-156 Reliability of the Oral Trail Making Test in a Teleneuropsychology Testing Environment

Objective

Despite the growing interest and literature supporting the validity and reliability of teleneuropsychology during the COVID-19 pandemic, little research exists on the reliability of the Oral Trail Making Test (OTMT) administered via videoconference. Previous work examining telephone administration of OTMT found good reliability across formats for Part B, but not Part A, suggesting further reliability studies on OTMT are needed.

Method

119 healthy aging controls and 84 individuals with mild cognitive impairment or dementia (M age = 68.37, SD = 9.57; 63% female; M education = 14.08, SD 2.73 years) were administered a brief neuropsychological battery including OTMT in counterbalanced face-to-face (FF) and videoconference (VC) conditions. T-tests and intraclass correlations (ICC’s) were used to compare results between testing conditions across groups.

Results

Among controls, the mean differences (MD) between conditions on OTMT-A (MD = -1.6, SD = 1.96) and B (MD = 1.6, SD = 54.77) were small, but statistically significant for OTMT-A; p &lt; 0.001 but not OTMT-B (p = 0.749). ICC’s reflected good (0.85) and moderate (0.66) agreement on OTMT-A and B, respectively. Within the cognitively impaired group, mean differences across conditions on OTMT-A (MD = 22.74, SD = 155.44) and OTMT-B (MD = 46.87, SD = 240.65) were nonsignificant (p = 0.18 and 0.08, respectively). ICC’s showed moderate agreement on OTMT-A (0.66) and B (0.53).

Conclusions

While similar mean OTMT scores were seen across test conditions, SD’s were large. ICC’s were only moderate, and scores on OTMT-A were even more variable than OTMT-B, similar to previous reports. Results support the utility of using the OTMT in teleneuropsychological assessment, but suggest cautious interpretation of findings given the variability in scores seen.

Frequency and Predictors of Traumatic Encephalopathy Syndrome in a Prospective Cohort of Retired Professional Athletes

Traumatic encephalopathy syndrome (TES) is proposed to represent the long-term impact of repetitive head-injury exposure and the clinical manifestation of chronic traumatic encephalopathy (CTE). This study aimed to evaluate the frequency of TES in a cohort of retired professional contact sport athletes, compare the frequency of TES to clinical consensus diagnoses, and identify predictors that increase the likelihood of TES diagnosis. Participants were 85 retired professional contact sport athletes from a prospective cohort at the University of Texas Southwestern Medical Center and the University of Texas at Dallas. Participants ranged in age from 23 to 79 (M = 55.95, SD = 13.82) and obtained 7 to 19 years of education (M = 16.08, SD = 1.03). Retirees were either non-Hispanic white (n = 62) or African-American (n = 23). Retired athletes underwent a standard clinical evaluation, which included a clinical interview, neurological exam, neuroimaging, neuropsychological testing, and consensus diagnosis of normal, mild cognitive impairment, or dementia. TES criteria were applied to all 85 athletes, and frequencies of diagnoses were compared. Fourteen predictors of TES diagnosis were evaluated using binary logistic regressions, and included demographic, neuropsychological, depression symptoms, and head-injury exposure variables. A high frequency (56%) of TES was observed among this cohort of retired athletes, but 54% of those meeting criteria for TES were diagnosed as cognitively normal via consensus diagnosis. Games played in the National Football League (OR = 0.993, p = 0.087), number of concussions (OR = 1.020, p = 0.532), number of concussions with loss of consciousness (OR = 1.141 p = 0.188), and years playing professionally (OR = 0.976, p = 0.627) were not associated with TES diagnosis. Degree of depressive symptomatology, as measured by the total score on the Beck Depression Inventory-II, was the only predictor of TES diagnosis (OR = 1.297, p < 0.001). Our results add to previous findings underscoring the risk for false positive diagnosis, highlight the limitations of the TES criteria in clinical and research settings, and question the relationship between TES and head-injury exposure. Future research is needed to examine depression in retired professional athletes.

Traumatic brain injury alters neuropsychiatric symptomatology in all-cause dementia

INTRODUCTION

Traumatic brain injury (TBI) may alter the course of neuropsychiatric symptom (NPS) onset during dementia development. The connection among TBI, NPS, and dementia progression is of increasing interest to researchers and clinicians.

METHODS

Incidence of NPS was examined in participants with normal cognition who progressed to all-cause dementia based on whether TBI history was present (n = 130) or absent (n = 849). Survival analyses were used to examine NPS incidence across 7.6 ± 3.0 years of follow-up.

RESULTS

Participants with TBI history had increased prevalence and incidence of apathy (44.7% vs 29.9%, P = .0062; HR_adj. = 1.708, P = .0018) and motor disturbances (17.2% vs 9.5%, P = .0458; HR_adj. = 2.023, P = .0168), controlling for demographics and type of dementia diagnosis. Earlier anxiety onset was associated with TBI (692 days prior to dementia diagnosis vs 161 days, P = .0265).

DISCUSSION

History of TBI is associated with increased risk for and earlier onset of NPS in the trajectory of dementia development.

Sex differences in reporting of concussion symptoms in adults

OBJECTIVE

To examine differences in concussion symptom reporting between female and male adults considering current psychological symptoms such as anxiety and depression and pre-injury factors in order to identify sex differences which may guide treatment efforts. Method: This prospective study is part of the North Texas Concussion Registry (ConTex). Subjects (N = 132) age 19 to 78 years had sustained a concussion within 30 days of clinic visit. The independent variable was sex and covariates included age, ethnicity, current anxiety and depression ratings, history of attention deficit disorder, history of headache/migraine, and time to clinic. The dependent variables were 22 post-concussion symptoms as measured by the Sport Concussion Assessment Tool-5 Post-Concussion Symptom Scale. Results: Analysis of covariance and ordinal logistic regression results both revealed that females had a greater likelihood of reporting increased symptom severity for 15/22 concussion symptoms. The largest risk ratios (effect size) in symptom reporting between sexes (higher symptoms in females) included: feeling more emotional 4.05 (0.72), fatigue or low energy 4.05 (0.72), sensitivity to light 3.74 (0.69), headache 3.65 (0.57), balance problems 3.31 (0.53), pressure in head 3.06 (0.51), and neck pain 2.97 (0.60). Conclusions: Adult females in our sample reported higher levels of many concussion symptoms than males and showed an increased risk of developing these same symptoms following concussion. Examination of the magnitude of sex difference in concussion symptom reporting will better inform medical staff to anticipate and address symptoms that may present greater challenges for adult females.

A Quantitative Analysis of Social Media to Determine Trends in Brain Tumor Care and Treatment

Background

Approximately 80,000 primary brain tumors are diagnosed annually. Social media provides a source of information and support for patients diagnosed with brain tumors; however, use of this forum for dissemination of information about brain tumors has not been evaluated. The objective of this study was to evaluate social media utilization and content related to brain tumors with an emphasis on patients’ trends in usage.

Methods

Social media platforms were systematically evaluated using two search methods: systematic manual inquiry and a keyword-based social media tracker. The search terms included brain tumor, glioblastoma, glioma, and glioblastoma multiforme. Social media content (which includes Facebook pages and groups, YouTube videos, and Twitter or Instagram accounts) and posts were assessed for activity (as quantified by views of posts) and analyzed using a categorization framework.

Results

The manual and keyword searches identified 946 sources of social media content, with a total count of 7,184,846 points of engagement. Social media platforms had significant variations in content type. YouTube was the largest social media platform for sharing content related to brain tumors overall, with an emphasis on surgical videos and documented patient experiences. Facebook accounted for the majority of patient-to-patient support, and Twitter was the most common platform for scientific dissemination. Overall social media content was mostly focused on treatment overviews and patient experience. When evaluated by search term, most social media posts by the “brain tumor” community shared illness narratives, and searches specific to “glioma” and “glioblastoma” demonstrated a higher proportion of educational and treatment posts.

Conclusions

This study presents novel observations of the characteristics of social media utilization for the online brain tumor community. A robust patient community exists online, with an emphasis on sharing personal narratives, treatment information, patient-to-patient support, treatment options, and fundraising events. This study provides a window to the role of social media utilization by patients, their families, and health professionals. These findings demonstrate the different roles of Facebook, YouTube, and Twitter in the rapidly changing era of social media and its relationship with neurosurgery and neuro-oncology.

Traumatic Brain Injury and Risk of Long-Term Brain Changes, Accumulation of Pathological Markers, and Developing Dementia: A Review

Traumatic brain injuries (TBI) have received widespread media attention in recent years as being a risk factor for the development of dementia and chronic traumatic encephalopathy (CTE). This has sparked fears about the potential long-term effects of TBI of any severity on cognitive aging, leading to a public health concern. This article reviews the evidence surrounding TBI as a risk factor for the later development of changes in brain structure and function, and an increased risk of neurodegenerative disorders. A number of studies have shown evidence of long-term brain changes and accumulation of pathological biomarkers (e.g., amyloid and tau proteins) related to a history of moderate-to-severe TBI, and research has also demonstrated that individuals with moderate-to-severe injuries have an increased risk of dementia. While milder injuries have been found to be associated with an increased risk for dementia in some recent studies, reports on long-term brain changes have been mixed and often are complicated by factors related to injury exposure (i.e., number of injuries) and severity/complications, psychiatric conditions, and opioid use disorder. CTE, although often described as a neurodegenerative disorder, remains a neuropathological condition that is poorly understood. Future research is needed to clarify the significance of CTE pathology and determine whether that can explain any clinical symptoms. Overall, it is clear that most individuals who sustain a TBI (particularly milder injuries) do not experience worse outcomes with aging, as the incidence for dementia is found to be less than 7% across the literature.

A-37 Neuropsychological Functioning In Cognitively Normal And Impaired Aging NFL Retirees

Objective

Identify differences in neuropsychological (NP) functioning between older (≥ 50) National Football League (NFL) retirees and age-matched controls, and examine whether differences correlate to head-injury exposure.

Method

NFL retirees were diagnosed with normal cognition (n = 20), mild cognitive impairment (n = 19), or dementia (n = 5) using Jak and Bondi (2009) criteria and clinical consensus. Retirees were age-matched to either healthy controls (n = 18) or clinical controls with MCI (n = 21) or dementia (n = 5). MANCOVAs and partial correlations covarying for age and education compared retiree’s NP performances to controls, and examined whether differences in NP measures were correlated with number of concussions, or games and years played in the NFL.

Results

Cognitively normal (CN) retirees displayed lower processing speed, naming, and verbal memory (p’s &lt; .05) than CN controls. Impaired retirees displayed worse processing speed and naming than impaired controls, but better verbal memory (p’s &lt; .05). Only lower verbal memory performance in CN retirees significantly correlated with number of games (r = −.60) and years played (r = −.54).

Conclusions

Aging CN and impaired retirees performed worse on single measures of processing speed and naming, but their performances did not correlate to head-injury exposure. Verbal memory performance varied between CN (worse than controls) and impaired retirees (better than controls). Overall, results suggest some aging NFL players may be at risk for reduced verbal memory, but this relationship could diminish following onset of MCI. No clear dose-response relationship was observed between head-injury exposure and NP functioning. Future studies should examine longitudinal trajectories of NP performances in larger samples to elucidate these findings.

Clinical and neuropsychological profile of patients with dementia and chronic traumatic encephalopathy

OBJECTIVE

To determine whether subjects with chronic traumatic encephalopathy (CTE) and dementia have distinct clinical features compared to subjects with pathologically confirmed Alzheimer's disease (AD).

METHODS

Among 339 subjects assessed for CTE in the National Alzheimer's Coordinating Center dataset, 6 subjects with CTE and 25 subjects with AD neuropathologic change matched for age (±5 years) and sex were identified. All subjects had a clinical diagnosis of dementia. Neurological examination, neuropsychological testing and emotional/behavioural data were compared between CTE and AD subjects at the time of dementia diagnosis and last clinical visit near death.

RESULTS

A history of traumatic brain injury with loss of consciousness (LOC) was reported in one CTE and one AD subject; information about injuries without LOC or multiple injuries was unavailable. CTE and AD subjects did not differ significantly at the time of diagnosis or last visit on the Unified Parkinson's Disease Rating Scale-Motor Exam, global measures of cognitive functioning (Mini-Mental State Exam and Clinical Dementia Rating Scale), emotional/behaviour symptoms as assessed with the Neuropsychiatric Inventory questionnaire or across neuropsychological measures. All CTE participants had co-occurring neuropathologic processes, including AD and most had TAR DNA-binding protein 43 (TDP-43) neuropathology.

CONCLUSIONS

CTE pathology was rare in a large multicentre national dataset, and when present, was accompanied by AD and TDP-43 pathologies. CTE was not associated with a different clinical presentation from AD or with greater cognitive impairment or neurobehavioral symptoms. These findings suggest that CTE may not have a distinct clinical profile when other neuropathologic processes are coexistent with CTE pathology.

Risk factors for earlier dementia onset in autopsy-confirmed Alzheimer's disease, mixed Alzheimer's with Lewy bodies, and pure Lewy body disease

INTRODUCTION

Clinical Alzheimer's disease (AD) and dementia with Lewy bodies often have mixed AD and Lewy pathology, making it difficult to delineate risk factors.

METHODS

Six risk factors for earlier dementia onset due to autopsy-confirmed AD (n = 647), mixed AD and Lewy body disease (AD + LBD; n = 221), and LBD (n = 63) were entered into multiple linear regressions using data from the National Alzheimer's Coordinating Center.

RESULTS

In AD and AD + LBD, male sex and apolipoprotein E (APOE) ɛ4 alleles each predicted a 2- to 3-year-earlier onset and depression predicted a 3-year-earlier onset. In LBD, higher education predicted earlier onset and depression predicted a 5.5-year-earlier onset.

DISCUSSION

Male sex and APOE ɛ4 alleles increase risk for earlier dementia onset in AD but not LBD. Depression increases risk for earlier dementia onset in AD, LBD, and AD + LBD, but evaluating the course, treatment, and severity is needed in future studies.

Neuropsychological functioning in ageing retired NFL players: a critical review

Recent discovery of chronic traumatic encephalopathy in former National Football League (NFL) players has led to a surge of papers investigating cognitive functioning in these former athletes. This critical review of the literature focused on the neuropsychological functioning in these ageing athletes, and included 22 articles published between 2013 and 2019, of which 13 reported on neuroradiological imaging and four focused on dose-response relationships of repetitive head injury on cognitive outcomes. Four studies suggest higher prevalence of MCI and neurodegenerative disease among NFL retirees, although a quantifiable risk and prevalence of cognitive impairment and dementia in these players remains unknown. Decreased verbal memory has been found in some players across multiple studies, though with unknown clinical significance due to small sample sizes, unreported effect sizes, and absence of longitudinal data. Studies investigating a dose-response relationship between cognitive decline and head injury have generated mixed findings utilizing various measures of head injury exposure. Neuroradiological findings are inconsistent, but suggest that some NFL players may be at greater risk for reduced white matter integrity. Future research is needed to understand the relationship between sports-related concussions and the risk of long-term cognitive decline and neurodegenerative disease in ageing NFL players.

History of traumatic brain injury interferes with accurate diagnosis of Alzheimer's dementia: a nation-wide case-control study

Traumatic brain injury (TBI) and Alzheimer's disease (AD) bear a complex relationship, potentially increasing risk of one another reciprocally. However, recent evidence suggests post-TBI dementia exists as a distinct neurodegenerative syndrome, confounding AD diagnostic accuracy in clinical settings. This investigation sought to evaluate TBI's impact on the accuracy of clinician-diagnosed AD using gold standard neuropathological criteria. In this preliminary analysis, data were acquired from the National Alzheimer's Coordinating Centre (NACC), which aggregates clinical and neuropathologic information from Alzheimer's disease centres across the United States. Modified National Institute on Aging-Reagan criteria were applied to confirm AD by neuropathology. Among participants with clinician-diagnosed AD, TBI history was associated with misdiagnosis (false positives) (OR = 1.351 [95% CI: 1.091-1.674], p = 0.006). Among participants without clinician-diagnosed AD, TBI history was not associated with false negatives. TBI moderates AD diagnostic accuracy. Possible AD misdiagnosis can mislead patients, influence treatment decisions, and confound research study designs. Further work examining the influence of TBI on dementia diagnosis is warranted.

Associations of Race-Ethnicity and History of Traumatic Brain Injury With Age at Onset of Alzheimer's Disease

OBJECTIVE

This study examined whether a history of traumatic brain injury (TBI) is associated with age at onset of Alzheimer's disease (AD) in three racial-ethnic groups.

METHODS

Data from 7,577 non-Hispanic Caucasian, 792 African American, and 870 Hispanic participants with clinically diagnosed AD were obtained from the National Alzheimer's Coordinating Center. Participants were categorized by the presence or absence of self-reported remote history of TBI (>1 year before diagnosis of AD) with loss of consciousness (LOC) (TBI+) or no history of TBI with LOC (TBI-). Any group differences in education; sex; APOE ε4 alleles; family history of dementia; or history of depression, stroke, hypertension, hypercholesterolemia, and diabetes were included in analyses of covariance comparing clinician-estimated age at AD symptom onset for the TBI+ and TBI- groups.

RESULTS

AD onset occurred 2.3 years earlier for non-Hispanic Caucasians (F=30.49, df=1, 7,572, p<0.001) and 3.4 years earlier for African Americans (F=5.17, df=1, 772, p=0.023) in the TBI+ group. In the Hispanic cohort, females in the TBI+ group had AD onset 5.6 years earlier, compared with females in the TBI- group (F=6.96, df=1, 865, p=0.008); little difference in age at AD onset was observed for Hispanic males with and without a TBI history.

CONCLUSIONS

A history of TBI with LOC was associated with AD onset 2-3 years earlier in non-Hispanic Caucasians and African Americans and an onset nearly 6 years earlier in Hispanic females; no association was observed in Hispanic males. Further work in underserved populations is needed to understand possible underlying mechanisms for these differences.

Traumatic Brain Injury and Age of Onset of Dementia with Lewy Bodies

BACKGROUND

Traumatic brain injury (TBI) with loss of consciousness (LOC) has been associated with earlier onset of mild cognitive impairment, frontotemporal dementia, Parkinson's disease, and Alzheimer's disease (AD), but has not been examined as a risk factor for earlier onset of dementia with Lewy bodies (DLB).

OBJECTIVE

The purpose of this study was to assess the association between a history of TBI and the age of onset of DLB.

METHOD

Data from 576 subjects with a clinical diagnosis of DLB were obtained from the National Alzheimer's Coordinating Center (NACC). Analyses of Covariance examined whether self-reported history of remote TBI with LOC (i.e., >1 year prior to the first Alzheimer's Disease Center visit) was associated with earlier DLB symptom onset.

RESULTS

Controlling for sex, those with a history of remote TBI had an approximately 1.5-year earlier clinician-estimated age of onset (F = 0.87, p = 0.35) and 0.75-years earlier age of diagnosis (F = 0.14, p = 0.71) of DLB compared to those without a history of TBI, though the differences did not reach statistical significance. Analysis of subjects with autopsy-confirmed diagnoses was underpowered due to the low number of TBI+ subjects.

CONCLUSIONS

Remote TBI with LOC was not significantly associated with DLB onset, despite being a significant risk factor for cognitive decline and earlier age of onset in other neurodegenerative conditions. Replication of these results using a larger cohort of DLB subjects with and without a TBI history who have undergone autopsy is indicated, as our TBI+ subjects did show a slightly earlier onset of about 1.5 years. Further investigations into other potential DLB risk factors are also warranted.

Annualized Decline in Instrumental Activities of Daily Living Is Slower in Hispanics Compared to Non-Hispanics in an Alzheimer’s Disease Sample

Objective

Research examining the course of Alzheimer’s disease (AD) in Hispanics is lacking. This study examined demographic, psychiatric, cognitive, and genetic predictors of longitudinal functional change in Hispanics and non-Hispanics with AD.

Method

Longitudinal change in instrumental activities of daily living (IADL) was examined over 10 years (M = 4.15 years) in 292 subjects (Hispanic = 67, non-Hispanic = 225). All were part of the Texas Alzheimer’s Research & Care Consortium and included those with AD (n = 217) and those with mild cognitive impairment at baseline who progressed to AD at follow-up (n = 75). Baseline comparisons were conducted between ethnic groups for demographics, Geriatric Depression Scale (GDS-30) score, Mini Mental State Examination (MMSE) score, presence of apolipoprotein ɛ4 alleles (APOE4), and annualized IADL change scores and then entered into a multiple linear regression model as predictors of annualized IADL change.

Results

The Hispanic group had significantly more females (χ2 = 5.71, p = .017), lower education [MH = 9.96(4.39), MNH = 15.26(2.70)], higher depression scores [GDS-30; MH = 9.45(5.89), MNH = 5.51(4.29)], lower MMSE scores [MH = 23.31(4.33), MNH = 24.65(3.21)], and slower annualized IADL change [MH = 1.19(1.42), MNH = 2.02(1.60)]. Regression results were significant (F = 3.66, p = .001, R2 = .08 ), with higher baseline MMSE (p = .007) and Hispanic origin (p = .010) predicting slower annualized IADL change. Demographics, APOE4 status, and depression did not significantly predict IADL change.

Conclusions

Higher cognitive functioning at baseline and Hispanic origin was associated with slower functional decline over an average 4-year period of time. Despite having lower MMSE scores at baseline, greater depression, and less education, the Hispanic group had a slower decline in IADLs compared to non-Hispanics. Further research is needed to better understand how/why Hispanic origin is associated with slower functional decline.

Predictors of Life Expectancy After an Alzheimer’s Disease Diagnosis in a National Multi-Center Autopsy-Confirmed Sample

Objective

Life expectancy varies between 3-12 years following the diagnosis of Alzheimer’s disease (AD) and is an important clinical question for patients and families. Current literature is limited by relatively small sample sizes and a reliance on clinical diagnoses. This study sought to evaluate predictors of AD life expectancy in a large autopsy-confirmed sample.

Methods

Baseline data from individuals 50 years and older clinically and neuropathologically diagnosed with AD (N=764) were obtained from the National Alzheimer’s Coordinating Center. Life expectancy was calculated in months from AD diagnosis to death. Nineteen variables (demographic, medical/health, disease severity, and psychiatric) obtained at dementia diagnosis were examined. Variables that showed significant differences in life expectancy using t-tests and Pearson correlations (14 of 19) were then entered into a forward multiple regression.

Results

Seven predictors in the model explained 27% of the variance in life expectancy (F= 40.7, R-squared= 0.267). Lower MMSE scores (β= 0.339, p < .001), male sex (β= -0.144, p < .001), older age (β= -0.130, p < .001), non-Hispanic Caucasian race/ethnicity (β= 0.115, p < .001), greater impairment on the Functional Activities Questionnaire (β= -0.091, p=.042), abnormal neurological/physical exam (β= -0.083, p=.011), and higher Neuropsychiatric Inventory Questionnaire total scores (β= -0.079, p=.016) predicted shorter life expectancy.

Conclusions

Global cognitive impairment, sex, age, race/ethnicity, functional impairment, abnormal neurological exam findings, and psychiatric symptoms explain a significant proportion of life expectancy following an AD diagnosis. Future studies should explore the relationship between life expectancy, specific neurological abnormalities, and psychiatric symptoms. These 7 predictors could potentially be used to predict life expectancy in individuals diagnosed with AD.

Reliability of Medical History Reporting in Older Adults With and Without Cognitive Impairment

BACKGROUND

Clinical diagnosis of cognitive disorders depends on accurate reporting of medical history, yet little is known about the reliability and the validity of such reports, particularly in older patients with and without cognitive impairment.

METHODS

In 2 studies, we examined the reliability and the validity of reported histories of select medical events in adults with and without cognitive impairment from a large national cohort.

RESULTS

Information from subjects (N1 = 3664), obtained from 2 time points, 6 to 12  months apart, was consistent across most medical events, regardless of the diagnostic group (range = 97.6%-100% agreement; Cohen κ range = 0.712-0.945), with few exceptions. Validity analyses (N2 = 382) revealed that 3 of 5 medical events assessed showed substantial agreement between self-report information and clinician diagnosis.

CONCLUSIONS

These data represent some of the first to demonstrate the reliability and the validity of reported select medical events in older adults with and without cognitive impairment.

Traumatic brain injury history and progression from mild cognitive impairment to Alzheimer disease

OBJECTIVE

To examine whether history of traumatic brain injury (TBI) is associated with more rapid progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

METHOD

Data from 2,719 subjects with MCI were obtained from the National Alzheimer's Coordinating Center. TBI was categorized based on presence (TBI+) or absence (TBI-) of reported TBI with loss of consciousness (LOC) without chronic deficit occurring >1 year prior to diagnosis of MCI. Survival analyses were used to determine if a history of TBI predicted progression from MCI to AD up to 8 years. Random regression models were used to examine whether TBI history also predicted rate of decline on the Clinical Dementia Rating scale Sum of Boxes score (CDR-SB) among subjects who progress to AD.

RESULTS

Across 8 years, TBI history was not significantly associated with progression from MCI to a diagnosis of AD in unadjusted (HR = 0.80; 95% CI [0.63, 1.01]; p = .06) and adjusted (p = .15) models. Similarly, a history of TBI was a nonsignificant predictor for rate of decline on CDR-SB among subjects who progressed to AD (b = 0.15, p = .38). MCI was, however, diagnosed a mean of 2.6 years earlier (p < .001) in TBI+ subjects compared with the TBI- group.

CONCLUSIONS

A history of TBI with LOC was not associated with progression from MCI to AD, but was linked to an earlier age of MCI diagnosis. These findings add to a growing literature suggesting that TBI might reduce the threshold for onset of MCI and certain neurodegenerative conditions, but appears unrelated to progression from MCI to AD. (PsycINFO Database Record

Traumatic brain injury history is associated with an earlier age of dementia onset in autopsy-confirmed Alzheimer's disease

OBJECTIVE

To evaluate whether a history of traumatic brain injury (TBI) with reported loss of consciousness (LOC) is a risk factor for earlier onset of Alzheimer's disease (AD) in an autopsy-confirmed sample.

METHOD

Data from 2,133 participants with autopsy-confirmed AD (i.e., at least Braak neurofibrillary tangle stages III to VI and CERAD neuritic plaque score moderate to frequent) were obtained from the National Alzheimer's Coordinating Center (NACC). Participants were categorized by presence/absence of self-reported remote (i.e., >1 year prior to their first Alzheimer's Disease Center visit) history of TBI with LOC (TBI+ vs. TBI-). Analyses of Covariance (ANCOVA) controlling for sex, education, and race compared groups on clinician-estimated age of symptom onset and age of diagnosis.

RESULTS

Average age of onset was 2.34 years earlier (p = .01) for the TBI+ group (n = 194) versus the TBI- group (n = 1900). Dementia was diagnosed on average 2.83 years earlier (p = .002) in the TBI+ group (n = 197) versus the TBI- group (n = 1936). Using more stringent neuropathological criteria (i.e., Braak stages V-VI and CERAD frequent), both age of AD onset and diagnosis were 3.6 years earlier in the TBI+ group (both p's < .001).

CONCLUSIONS

History of TBI with reported LOC appears to be a risk factor for earlier AD onset. This is the first study to use autopsy-confirmed cases, supporting previous investigations that used clinical criteria for the diagnosis of AD. Further investigation as to possible underlying mechanisms of association is needed. (PsycINFO Database Record

Neurodegenerative Dementias After Traumatic Brain Injury

Traumatic brain injury (TBI) is often considered to be a risk factor for the later development of neurodegenerative conditions, but some findings do not support a link. Differences in research methods, clinical samples, and limitations encountered when assessing and documenting TBI details likely contribute to the mixed reports in the literature. Despite some variability in findings, a review of the literature does provide support for the notion that TBI appears to be associated with earlier onset of some neurodegenerative disorders, although clearly not everyone with a TBI appears to be at an increased risk. Whereas a mechanistic link remains unknown, TBI has been found to initiate an accumulation of pathological processes related to several neurodegenerative disorders. The authors propose a hypothetical model that relates TBI to the development of pathological burden overlapping with some neurodegenerative conditions, in which onset of cognitive/behavioral impairments is hastened in some individuals, but pathological processes stabilize afterward, resulting in a similar course of decline to individuals with dementia who do not have a history of TBI.