Young Military Veterans Research Articles

Body Armor and Lumbar Disc Herniation in Young Military Veterans: A Case Series.

Soldiers on the battlefield are affected by heavy body armor and excessive march load. It is well known, but the long-term effects of this extra weight on the musculoskeletal system of military veterans, specifically the lumbar spine, are unclear. In Iraq and Afghanistan, most body armors weighed over 33 pounds (15 kg). These armors were 3 times heavier than those used in Vietnam. Chiropractors at the Fargo VA Hospital are seeing more young veterans with non-traumatic lower back pain. This article presents a perspective on the impact of body armor weight and excessive carry load on lumbosacral disc herniation with radicular pain in military veterans. This study is a retrospective case series. We used a convenient sampling method. We selected the first 10 military veterans who came to a Fargo VA chiropractor in late fall 2023. Each veteran filled out a VA Form 10-5345 to give us permission to access their electronic health records. All 10 veterans also completed a survey. The survey asked about their active combat status, the type and weight of their body armor, how long they wore the armor each day, how much weight they carried, and their opinion on the cause of their lower back pain (service related or not). The Fargo VA does not require an institutional review board for a case series. This study found that military veterans experience lower back pain at an average age of 35 years. This is at least 5 years earlier than non-service men. Lower back pain with disc herniation typically occurs at the L4-L5 and L5-S1 disc levels. All 10 veterans in the study believe that their lower back pain is related to their service. Sixty percent of the participants in the study have a service-connected disability because of back pain. For military veterans, onset of lower back pain from a disc herniation at a young age may be linked to carrying heavy body armor and loads. However, the small sample size of this case series limits causal relationship inferences.

Evoked Potentials Reveal Noise Exposure-Related Central Auditory Changes Despite Normal Audiograms.

Purpose Complaints of auditory perceptual deficits, such as tinnitus and difficulty understanding speech in background noise, among individuals with clinically normal audiograms present a perplexing problem for audiologists. One potential explanation for these "hidden" auditory deficits is loss of the synaptic connections between the inner hair cells and their afferent auditory nerve fiber targets, a condition that has been termed cochlear synaptopathy. In animal models, cochlear synaptopathy can occur due to aging or exposure to noise or ototoxic drugs and is associated with reduced auditory brainstem response (ABR) wave I amplitudes. Decreased ABR wave I amplitudes have been demonstrated among young military Veterans and non-Veterans with a history of firearm use, suggesting that humans may also experience noise-induced synaptopathy. However, the downstream consequences of synaptopathy are unclear. Method To investigate how noise-induced reductions in wave I amplitude impact the central auditory system, the ABR, the middle latency response (MLR), and the late latency response (LLR) were measured in 65 young Veterans and non-Veterans with normal audiograms. Results In response to a click stimulus, the MLR was weaker for Veterans compared to non-Veterans, but the LLR was not reduced. In addition, low ABR wave I amplitudes were associated with a reduced MLR, but with an increased LLR. Notably, Veterans reporting tinnitus showed the largest mean LLRs. Conclusions These findings indicate that decreased peripheral auditory input leads to compensatory gain in the central auditory system, even among individuals with normal audiograms, and may impact auditory perception. This pattern of reduced MLR, but not LLR, was observed among Veterans even after statistical adjustment for sex and distortion product otoacoustic emission differences, suggesting that synaptic loss plays a role in the observed central gain. Supplemental Material https://doi.org/10.23641/asha.11977854.

Using affinity diagramming to generate a codebook: a case study on young military veterans and community reintegration

Use of a codebook to categorize meaning units is a well-known research strategy in qualitative inquiry. However, methodology for the creation of a codebook in practice is not standardized, and specific guidance for codebook ideation is sometimes unclear, especially to novice qualitative researchers. This article describes the procedure that was utilized to create a codebook, which adapted an affinity diagram methodology (Scupin, 1997), an approach used in user-centered design. For this research, affinity diagramming was applied to a method outlined by Kurasaki (2000) for codebook ideation. Annotations of a subset of military veterans’ transcripts were utilized in congruence with affinity diagramming to create a codebook to categorize the phenomenon of reintegration into the civilian community after service (Haskins Lisle, 2017). This method could be useful in exploratory research that utilizes a codebook generated in vivo from annotations, especially for novice researchers who are overwhelmed by the codebook creation phase.

Characterizing noise-induced hidden hearing loss in veterans

Cochlear synaptopathy, the partial loss of auditory nerve synapses onto inner hair cells, has been proposed as a possible source of hyperacusis, some forms of tinnitus, and difficulty understanding speech in background noise. In animal models, cochlear synaptopathy is associated with a reduction in the amplitude of wave I of the auditory brainstem response (ABR) and can occur even when auditory thresholds are normal. This presentation will discuss noise exposure-related changes to several auditory physiological measures, including the ABR, in young military Veterans with clinically normal pure tone thresholds. Veterans show differences from non-Veteran controls even after statistically adjusting for group differences in sex and otoacoustic emissions, suggestive of synaptic or neuronal loss. While these physiological changes do not appear to be associated with decreased performance on standard speech-in-noise tests, they are associated with the report of frequent or constant tinnitus. Although post-mortem histological analysis would be necessary for confirmation, these data are consistent with animal models of cochlear synaptopathy and suggest that synaptopathy or “hidden hearing loss” may occur in response to high intensity noise exposure in humans and be correlated with tinnitus.

Tinnitus and Auditory Perception After a History of Noise Exposure: Relationship to Auditory Brainstem Response Measures.

To determine whether auditory brainstem response (ABR) wave I amplitude is associated with measures of auditory perception in young people with normal distortion product otoacoustic emissions (DPOAEs) and varying levels of noise exposure history. Tinnitus, loudness tolerance, and speech perception ability were measured in 31 young military Veterans and 43 non-Veterans (19 to 35 years of age) with normal pure-tone thresholds and DPOAEs. Speech perception was evaluated in quiet using Northwestern University Auditory Test (NU-6) word lists and in background noise using the words in noise (WIN) test. Loudness discomfort levels were measured using 1-, 3-, 4-, and 6-kHz pulsed pure tones. DPOAEs and ABRs were collected in each participant to assess outer hair cell and auditory nerve function. The probability of reporting tinnitus in this sample increased by a factor of 2.0 per 0.1 µV decrease in ABR wave I amplitude (95% Bayesian confidence interval, 1.1 to 5.0) for males and by a factor of 2.2 (95% confidence interval, 1.0 to 6.4) for females after adjusting for sex and DPOAE levels. Similar results were obtained in an alternate model adjusted for pure-tone thresholds in addition to sex and DPOAE levels. No apparent relationship was found between wave I amplitude and either loudness tolerance or speech perception in quiet or noise. Reduced ABR wave I amplitude was associated with an increased risk of tinnitus, even after adjusting for DPOAEs and sex. In contrast, wave III and V amplitudes had little effect on tinnitus risk. This suggests that changes in peripheral input at the level of the inner hair cell or auditory nerve may lead to increases in central gain that give rise to the perception of tinnitus. Although the extent of synaptopathy in the study participants cannot be measured directly, these findings are consistent with the prediction that tinnitus may be a perceptual consequence of cochlear synaptopathy.

Biological predictors of insulin resistance associated with posttraumatic stress disorder in young military veterans

Posttraumatic stress disorder (PTSD) is associated with increased risk for Type 2 diabetes and cardiovascular disease (cardiometabolic disease), warranting research into targeted prevention strategies. In the present case–control study of 160 young (mean age 32.7 years) male military veterans, we aimed to assess whether PTSD status predicted increased markers of cardiometabolic risk in otherwise healthy individuals, and further, to explore biological pathways between PTSD and these increased markers of cardiometabolic risk. Toward these aims, we compared measures of cardiometabolic risk, namely insulin resistance (IR) (HOMA-IR), metabolic syndrome (MetS) and prediabetes, between 80 PTSD cases and 80 controls without PTSD. We then determined whether PTSD-associated increases in HOMA-IR were correlated with select biological variables from pathways previously hypothesized to link PTSD with cardiometabolic risk, including systemic inflammation (increased C-reactive protein, interleukin-6, and tumor necrosis factor α), sympathetic over-activity (increased resting heart rate), and neuroendocrine dysregulation (increased plasma cortisol or serum brain-derived neurotrophic factor (BDNF)). We found PTSD diagnosis was associated with substantially higher HOMA-IR (cases 4.3±4.3 vs controls 2.4±2.0; p<0.001), and a higher frequency of MetS (cases 21.3% vs controls 2.5%; p<0.001), but not prediabetes (cases 20.0% vs controls 18.8%; p>0.05). Cases also had increased pro-inflammatory cytokines (p<0.01), heart rate (p<0.001), and BDNF (p<0.001), which together predicted increased HOMA-IR (adjusted R2=0.68, p<0.001). Results show PTSD diagnosis in young male military veterans without cardiometabolic disease is associated with increased IR, predicted by biological alterations previously hypothesized to link PTSD to increased cardiometabolic risk. Findings support further research into early, targeted prevention of cardiometabolic disease in individuals with PTSD.

Auditory Brainstem Response Altered in Humans With Noise Exposure Despite Normal Outer Hair Cell Function.

Recent animal studies demonstrated that cochlear synaptopathy, a partial loss of inner hair cell-auditory nerve fiber synapses, can occur in response to noise exposure without any permanent auditory threshold shift. In animal models, this synaptopathy is associated with a reduction in the amplitude of wave I of the auditory brainstem response (ABR). The goal of this study was to determine whether higher lifetime noise exposure histories in young people with clinically normal pure-tone thresholds are associated with lower ABR wave I amplitudes. Twenty-nine young military Veterans and 35 non Veterans (19 to 35 years of age) with normal pure-tone thresholds were assigned to 1 of 4 groups based on their self-reported lifetime noise exposure history and Veteran status. Suprathreshold ABR measurements in response to alternating polarity tone bursts were obtained at 1, 3, 4, and 6 kHz with gold foil tiptrode electrodes placed in the ear canal. Wave I amplitude was calculated from the difference in voltage at the positive peak and the voltage at the following negative trough. Distortion product otoacoustic emission input/output functions were collected in each participant at the same four frequencies to assess outer hair cell function. After controlling for individual differences in sex and distortion product otoacoustic emission amplitude, the groups containing participants with higher reported histories of noise exposure had smaller ABR wave I amplitudes at suprathreshold levels across all four frequencies compared with the groups with less history of noise exposure. Suprathreshold ABR wave I amplitudes were reduced in Veterans reporting high levels of military noise exposure and in non Veterans reporting any history of firearm use as compared with Veterans and non Veterans with lower levels of reported noise exposure history. The reduction in ABR wave I amplitude in the groups with higher levels of noise exposure cannot be accounted for by sex or variability in outer hair cell function. This change is similar to the decreased ABR wave I amplitudes observed in animal models of noise-induced cochlear synaptopathy. However, without post mortem examination of the temporal bone, no direct conclusions can be drawn concerning the presence of synaptopathy in the study groups with higher noise exposure histories.

We are different now? The effect of military service on youth reintegration and employment in South Africa

This study examines how young people who have joined the South African National Defence Force (SANDF) on the two-year Military Skills Development System (MSDS) contract experience military service, and the effect this has on their ability to readapt to civilian life. The first part of the study examines the theoretical debates associated with military socialisation and reintegration into civilian life. Hereafter, the findings are presented in terms of the experiences of MSDS privates serving in the infantry, those that have left, and the perceptions of employment agencies in terms of the marketability of military skills. The conclusion is reached that MSDS members experience their two years in the SANDF as life-changing, that this affects their ability to reintegrate back into civilian society, and that the skills acquired during military training is of limited market value. The conclusion is reached that more needs to be done to assist these young military veterans to adapt to civilian life and to augment their military experience with more marketable skills to enable them to find gainful employment.