Disparities in Access to Deep Brain Stimulation for Parkinson's Disease and Proposed Interventions: A Literature Review

BACKGROUND

Deep brain stimulation (DBS) is an effective therapy for Parkinson's disease (PD), but disparities exist in access to DBS along gender, racial, and socioeconomic lines.

SUMMARY

Women are underrepresented in clinical trials and less likely to undergo DBS compared to their male counterparts. Racial and ethnic minorities are also less likely to undergo DBS procedures, even when controlling for disease severity and other demographic factors. These disparities can have significant impacts on patients' access to care, quality of life, and ability to manage their debilitating movement disorders.

KEY MESSAGES

Addressing these disparities requires increasing patient awareness and education, minimizing barriers to equitable access, and implementing diversity and inclusion initiatives within the healthcare system. In this systematic review, we first review literature discussing gender, racial, and socioeconomic disparities in DBS access and then propose several patient, provider, community, and national-level interventions to improve DBS access for all populations.

Reward Circuit Local Field Potential Modulations Precede Risk Taking

Risk taking behavior is a symptom of multiple neuropsychiatric disorders and often lacks effective treatments. Reward circuitry regions including the amygdala, orbitofrontal cortex, insula, and anterior cingulate have been implicated in risk-taking by neuroimaging studies. Electrophysiological activity associated with risk taking in these regions is not well understood in humans. Further characterizing the neural signalling that underlies risk-taking may provide therapeutic insight into disorders associated with risk-taking. Eleven patients with pharmacoresistant epilepsy who underwent stereotactic electroencephalography with electrodes in the amygdala, orbitofrontal cortex, insula, and/or anterior cingulate participated. Patients participated in a gambling task where they wagered on a visible playing card being higher than a hidden card, betting $5 or $20 on this outcome, while local field potentials were recorded from implanted electrodes. We used cluster-based permutation testing to identify reward prediction error signals by comparing oscillatory power following unexpected and expected rewards. We also used cluster-based permutation testing to compare power preceding high and low bets in high-risk (<50% chance of winning) trials and two-way ANOVA with bet and risk level to identify signals associated with risky, risk averse, and optimized decisions. We used linear mixed effects models to evaluate the relationship between reward prediction error and risky decision signals across trials, and a linear regression model for associations between risky decision signal power and Barratt Impulsiveness Scale scores for each patient. Reward prediction error signals were identified in the amygdala (p=0.0066), anterior cingulate (p=0.0092), and orbitofrontal cortex (p=6.0E-4, p=4.0E-4). Risky decisions were predicted by increased oscillatory power in high-gamma frequency range during card presentation in the orbitofrontal cortex (p=0.0022), and by increased power following bet cue presentation across the theta-to-beta range in the orbitofrontal cortex ( p =0.0022), high-gamma in the anterior cingulate ( p =0.0004), and high-gamma in the insula ( p =0.0014). Risk averse decisions were predicted by decreased orbitofrontal cortex gamma power ( p =2.0E-4). Optimized decisions that maximized earnings were preceded by decreases within the theta to beta range in orbitofrontal cortex ( p =2.0E-4), broad frequencies in amygdala ( p =2.0E-4), and theta to low-gamma in insula ( p =4.0E-4). Insula risky decision power was associated with orbitofrontal cortex high-gamma reward prediction error signal ( p =0.0048) and with patient impulsivity ( p =0.00478). Our findings identify and help characterize reward circuitry activity predictive of risk-taking in humans. These findings may serve as potential biomarkers to inform the development of novel treatment strategies such as closed loop neuromodulation for disorders of risk taking.

Sport-related concussion in 8- to 12-year-olds: an understudied population

OBJECTIVE

Most studies regarding sport-related concussion (SRC) focus on high school and collegiate athletes; however, little has been published on children younger than 12 years of age. In a cohort of children aged 8-12 years with SRC, the authors sought to describe demographics, initial presentation, and recovery in this understudied population.

METHODS

A retrospective cohort study of children aged 8-12 years who sustained an SRC between November 2017 and April 2022 and were treated at a regional sports concussion center was conducted. Demographic information, injury characteristics, traditional Sport Concussion Assessment Tool 5 (SCAT5) and Child/Parent SCAT5 scores, and outcomes, defined as days to return to learn (RTL), symptom resolution, and return to play (RTP), were reported. Outcomes in boys and girls were compared using effect size analyses given sample size constraints.

RESULTS

Forty-seven athletes were included. The mean age was 11.0 ± 0.8 years, and the majority were male (34, 72.3%). A sizable proportion of patients visited an emergency department (19, 40.4%), and many received head imaging (16, 34.0%), mostly via CT (n = 13). The most common sport for boys was football (15, 44.1%), and the most common sports for girls were soccer (4, 30.8%) and cheerleading (4, 30.8%). These athletes reported a variety of symptoms on presentation. It took a mean of 8.8 ± 10.8 days to RTL, 27.3 ± 38.3 days to reach symptom resolution, and 35.4 ± 41.9 days to RTP. When comparing boys versus girls, there appeared to be moderate differences in symptom severity scores (Cohen's d = 0.44 for SCAT5, 0.13 for Child SCAT5, and 0.38 for Parent SCAT5) and minimal differences in recovery (Cohen's d = 0.11 for RTL, n = 35; 0.22 for symptom resolution, n = 22; and 0.12 for RTP, n = 21).

CONCLUSIONS

In this cohort of concussed athletes aged 8-12 years, a little less than half of the athletes initially presented to the emergency department, and approximately one-third received acute head imaging. Across all athletes, the mean RTL was slightly more than a week and the mean symptom resolution and RTP were both approximately 1 month; however, much of the cohort is missing recovery outcome measures. This study demonstrated a strong positive correlation between Child SCAT5 and Parent SCAT5 symptom reporting. Future efforts are needed to evaluate differences in clinical presentation and outcomes following SRC between children and older populations.

Electrode position and cognitive outcome following deep brain stimulation surgery

OBJECTIVE

Subthalamic nucleus (STN) and globus pallidus internus (GPI) deep brain stimulation (DBS) effectively treat motor symptoms in Parkinson's disease (PD) but may be associated with cognitive and psychiatric changes in some patients. Evaluation of changes in cognitive and psychiatric symptoms following DBS is complicated by changes in these symptoms that occur as part of the natural disease course. The aim of this study was to evaluate whether electrode position was associated with changes in neurocognitive symptoms in patients who underwent STN and GPI DBS.

METHODS

A single-institution retrospective cohort study was conducted on patients with PD who underwent DBS from 2008 to 2019. Cognitive and psychiatric outcomes included Beck Depression Inventory II (BDI-II) score, presence of impulsive-compulsive behavior (ICB), Mini-Mental State Examination (MMSE) score, and overall cognitive status grade determined by comprehensive neuropsychology testing (normal, mild impairment, moderate impairment, and dementia). Pre- and postoperative comparisons were performed using a Wilcoxon signed-rank test or paired t-test. Patients with and without cognitive decline were compared using a Mann-Whitney U-test or unpaired t-test. A chi-square test was used for categorical comparisons.

RESULTS

One hundred thirty patients were included (mean age 62.5 ± 7.9 years). At a mean postoperative follow-up from DBS of 13.0 ± 12.7 (range 6-66) months, there was an improvement in ICB (26.3% preoperatively vs 15.0% postoperatively, p = 0.017), but a decline in MMSE score (28.6 ± 1.6 vs 27.6 ± 2.0, p < 0.001) and overall cognitive status (normal: 66.2% vs 39.2%; mild: 12.3% vs 17.7%; moderate: 21.5% vs 33.1%; dementia: 0.0% vs 10.0%; p < 0.001). Patients undergoing STN DBS had a worse decline in overall cognitive status than patients who underwent GPI DBS (p = 0.006). Postoperative cognitive decline was associated with a more medial electrode position only for patients who underwent STN DBS.

CONCLUSIONS

Cognitive change was observed in some patients with PD who underwent both GPI and STN DBS, likely due partly to underlying disease progression. Compared with GPI DBS, STN DBS was associated with a greater likelihood of cognitive decline. In STN but not GPI DBS, cognitive decline was associated with medialized electrode position, suggesting modulation of nonmotor STN divisions may contribute to cognitive changes following STN DBS.

Does earlier vestibular therapy after sport-related concussion lead to faster recovery?

OBJECTIVE

Many patients experience vestibular dysfunction following a sport-related concussion (SRC). Vestibular rehabilitation therapy has recently become more well established. In a cohort of athletes with SRC, the authors sought to 1) assess the relationship between symptoms at the initial clinic visit and time to referral for vestibular therapy, and 2) evaluate whether earlier referral to vestibular therapy was associated with faster recovery, as defined as days to return to learn (RTL), symptom resolution (SR), and return to play (RTP).

METHODS

A retrospective cohort study was conducted using a regional multidisciplinary concussion center's database. Patients aged 12-23 years diagnosed with SRC who received vestibular rehabilitation therapy between October 2017 and October 2021 were included. Demographics and Post-Concussion Symptom Scale (PCSS) scores were extracted. The independent variable of interest was time to vestibular therapy referral. The three outcome variables were RTL, SR, and RTP. Spearman's rho correlation (rho) was used to evaluate the relationship between total PCSS score and individual symptoms (balance problems, blurred vision, and dizziness) and time to referral for vestibular therapy. Multivariable linear regression was performed to determine the impact of time to vestibular therapy on the three outcomes of RTL, SR, and RTP. Covariates included initial symptom burden, age, and prior concussions.

RESULTS

Forty-two concussed athletes were referred for vestibular therapy (mean age 16.8 ± 2.7 years; 54.8% female). The mean time from concussion to the initial clinic visit was 22.4 ± 20.2 days, and the mean time from the initial clinic visit to vestibular therapy referral was 4.9 ± 11.3 days. Initial total PCSS scores (rho[37] = 0.05, p = 0.78) and individual symptoms, including balance problems (rho[33] = -0.004, p = 0.98), blurred vision (rho[34] = -0.17, p = 0.33), and dizziness (rho[33] = 0.07, p = 0.67), were not correlated with time to referral for vestibular therapy. Multivariable linear regression analysis found that earlier vestibular therapy referral was predictive of shorter days to SR (p = 0.002) and RTP (p = 0.02) but not RTL (p = 0.59).

CONCLUSIONS

In athletes with SRC referred for vestibular therapy, earlier vestibular therapy referral was significantly associated with faster time to RTP and SR. Future investigations should focus on identifying common postconcussive signs and symptoms that serve as indications for referral to vestibular therapy.

P188 Therapy in In Vitro Models of Traumatic Brain Injury

Traumatic brain injury (TBI) is a significant cause of morbidity and mortality worldwide. Varied mechanisms of injury contribute to the heterogeneity of this patient population as demonstrated by the multiple published grading scales and diverse required criteria leading to diagnoses from mild to severe. TBI pathophysiology is classically separated into a primary injury that is characterized by local tissue destruction as a result of the initial blow, followed by a secondary phase of injury constituted by a score of incompletely understood cellular processes including reperfusion injury, disruption to the blood-brain barrier, excitotoxicity, and metabolic dysregulation. There are currently no effective pharmacological treatments in the wide-spread use for TBI, in large part due to challenges associated with the development of clinically representative in vitro and in vivo models. Poloxamer 188 (P188), a Food and Drug Administration-approved amphiphilic triblock copolymer embeds itself into the plasma membrane of damaged cells. P188 has been shown to have neuroprotective properties on various cell types. The objective of this review is to provide a summary of the current literature on in vitro models of TBI treated with P188.

Intralipid fails to rescue bupivacaine-induced cardiotoxicity in late-pregnant rats

Background

Females routinely receive bupivacaine for obstetric and regional anesthesia. An accidental overdose of bupivacaine can result in cardiotoxicity and cardiac arrest. Intralipid (ILP) rescues bupivacaine-induced cardiotoxicity in male rats. However, bupivacaine cardiotoxicity and ILP rescue have not been studied in non-pregnant and late-pregnant female rats. Here, we tested the hypothesis that an appropriate dose of ILP would rescue non-pregnant and late-pregnant rats from bupivacaine-induced cardiotoxicity.

Methods

Non-pregnant (n = 6) and late-pregnant (n = 7) female rats received intravenous bupivacaine (10-mg/kg bolus) to induce asystole. Resuscitation with 20% ILP (5-ml/kg actual body weight, single bolus, and 0.5-ml/kg/min maintenance) and chest compressions were continued for 10-min. Serial heart rate (HR), left ventricular ejection-fraction (LVEF%), and LV-fractional shortening (LVFS%) were recorded at baseline and 10-min after bupivacaine-induced cardiac arrest. Data are mean ± SD followed by 95% CI. P-values < 0.05 were considered statistically significant.

Results

All rats developed cardiac arrest within a few seconds after bupivacaine. All non-pregnant rats were successfully rescued by ILP, with a HR of 280 ± 32 bpm at baseline vs. 212 ± 18 bpm at 10-min post ILP (p < 0.01), LVEF of 70 ± 6% vs. 68 ± 5% (p = ns), and LVFS of 41 ± 5% vs. 39 ± 4% (p = ns). Interestingly, 6 out of 7 late-pregnant rats did not recover with ILP. Baseline HR, LVEF and LVFS for late-pregnant rats were 330 ± 40 bpm, 66 ± 5% and 38 ± 4%, respectively. At 10-min post ILP, the HR, LVEF, and LVFS were 39 ± 102 bpm (p < 0.0001), 8 ± 22% (p < 0.0001), and 5 ± 12% (p < 0.001), respectively.

Conclusions

ILP successfully rescued bupivacaine-induced cardiac arrest in non-pregnant rats, but failed to rescue late-pregnant rats.

The Role of Estrogen Receptors in Cardiovascular Disease

Cardiovascular Diseases (CVDs) are the leading cause of death globally. More than 17 million people die worldwide from CVD per year. There is considerable evidence suggesting that estrogen modulates cardiovascular physiology and function in both health and disease, and that it could potentially serve as a cardioprotective agent. The effects of estrogen on cardiovascular function are mediated by nuclear and membrane estrogen receptors (ERs), including estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and G-protein-coupled ER (GPR30 or GPER). Receptor binding in turn confers pleiotropic effects through both genomic and non-genomic signaling to maintain cardiovascular homeostasis. Each ER has been implicated in multiple pre-clinical cardiovascular disease models. This review will discuss current reports on the underlying molecular mechanisms of the ERs in regulating vascular pathology, with a special emphasis on hypertension, pulmonary hypertension, and atherosclerosis, as well as in regulating cardiac pathology, with a particular emphasis on ischemia/reperfusion injury, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction.

Antioxidant activities of Eryngium caucasicum inflorescence

OBJECTIVE

Medicinal plants are good sources for discovery of safe and new antioxidants. The aim of present study was to evaluate the efficiencies of three methods for evaluated for antioxidants from Eryngium caucasicum.

MATERIALS AND METHODS

Ultrasonically assisted extraction, Soxhlet extraction and percolation method were evaluated for the extraction of antioxidants from E. caucasicum inflorescence. Antioxidant activities of extracts were evaluated with four different in vitro tests.

RESULTS

Soxhlet extract had higher total phenolic and flavonoid contents than other extracts. Soxhlet extract showed the highest activity in DPPH radical scavenging (IC50 = 83.1 ± 2.1 µg ml-1). Soxhlet extract showed the best activity in iron chelatory (IC50 = 272 ± 6.3 µg ml-1) followed by ultrasonic extract. Percolation extract showed higher NO radical scavenging (IC50 = 390 ± 11.4 µg ml-1) than other extracts. Extracts showed good reducing power (p > 0.05).

CONCLUSIONS

The results obtained indicated that all three extraction methods especially Soxhlet method could effectively extract antioxidants from this plant.

Frequency of ABO blood group in peptic ulcer disease in Iranian subjects

The relationship between ABO blood group distribution and Peptic Ulcer Disease (PUD) has been widely evaluated in the past. But data concerning the same evaluation are very limited in Iran. This study sought to determine the distribution of ABO blood group in patients with PUD in Iranian subjects. Eighty-one patients with PUD (51 male and 30 female; mean age: 49 +/- 18 years) who attended our endoscopy section were enrolled. Blood samples were used for ABO/Rhesus (Rh) blood group antigen typing. The ABO blood group phenotype distribution in subjects was as follows: 37.1% (30/81) for group A, 23.4% (19/81) for group B, 35.6% (28/81) for group O and 4.9% (4/81) for group AB. Rh positivity was found in 63% (51/81) of patients. In local healthy population, ABO/Rh blood group distribution was 33.8, 20.7, 34.7, 8.4 and 89.6% for A, B, O, AB and Rh, respectively. AB blood group distribution in healthy population was higher than PUD (8.4 vs 4.9%). In contrast, Rh positivity of PUD in Iran is lower than healthy subjects (63 vs 89.6%). Variation in the results of studies is related to different study communities. According to these results, probably ABO/Rh blood group has an important role in patients with peptic ulceration. The functional significance of ABO blood group distribution might be associated with biological behavior of PUD. The impact of blood group on PUD may be a focus for further studies.