bluuebunny/crossref_metadata_2025 huggingface dataset:
Dosimetry needs for MRI-linacs
Authors: Jelen U , Begg J
Published: August 2019

The pursuit of real-time image-guided radiotherapy has prompted the development of hybrid devices coupling MRI scanners with radiotherapy treatment units, usually linear accelerators (linacs). One of the challenges in MRI-linac technology is the magnetic field impact on the dose deposition. Dose deposition effects have to be considered in the radiation therapy chain as they alter the dose distribution in patients and influence the response of many commonly used radiation detectors. In this presentation specific issues of dosimetry for MRI-linacs will be reviewed and illustrated with examples from the Australian MRI-linac commissioning process.
Polymer gel dosimetry in the presence of a strong magnetic field
Authors: Roed Y , Pinsky L , Ibbott G
Published: August 2019

The integration of magnetic resonance (MR) imagers with radiotherapy units provided a new opportunity to demonstrate the value of polymer gels as volumetric dosimeters. The purpose of this work was to investigate the use of methacrylic-acid based polymer gels for quality assurance of patient-specific treatment plans delivered with these novel treatment machines. The characterization of the gel was performed while the gel was subjected to a strong magnetic field and in the absence of the magnetic field. Additionally, an end-to-end phantom study was conducted using an MR image-guided radiotherapy (MR-IGRT) unit. This data will be used to support the implementation of volumetric dosimeters in MR-IGRT.
Measurement of build-up region dose with optical cone-beam computed tomography scanner
Authors: Garisto Sarah , Jordan Kevin
Published: August 2019

Measurement of the dose gradients from the entrance surface to depth is a standard task for characterizing an ionizing radiation beam. Most gel dosimeters provide spurious results near an air interface, limiting their value for this geometry. In this study, a 3D dosimeter system consisting of a low-diffusion, radiochromic hydrogel cast in a custom polyethylene terephthalate (PETE) vessel and imaged with a modified commercial optical cone-beam computed tomography (CBCT) scanner was employed. The cylindrical vessel wall and flat ends were constructed from a 0.025 cm thick PETE sheet. The optical CBCT scanner was modified to place the entire vessel in the centre of the field of view or to have the vessel base at the optical axis. Pre-irradiation and post-irradiation scans were acquired with the sample mounted in the standard and elevated positions. The sample was irradiated with a 2x2 cm square, 6 MV x-ray beam. Normalized attenuation coefficients from the central quarter of the reconstructed beam images were compared to a Monte Carlo depth dose calculation. Placing the vessel base at the optical axis allowed accurate dose measurements to within 0.2 cm of the entrance face and for the standard position to within 0.4 cm. These measurements validated the Monte Carlo calculation and provide an alternative to parallel plate ion chambers for dose measurement in the build-up region.
Feasibility study of a dry optical CT scanner using aspherical lenses
Authors: De Deene Yves
Published: August 2019

Dry scanners have been proposed as alternatives to scanners in which a refractive index matching fluid is used. Previous dry scanners either have a small field-of-view or employ a thick cast with a higher refractive index than the phantom. This may not always be feasible. A new design is proposed in this study where two aspherical meniscus lenses are employed to direct the laser beams in parallel lines through the phantom.
Assessing CBCT-based patient positioning accuracy on the Gamma Knife IconTM via Presage® 3D absolute dosimetry
Authors: Xu Andy Y. , Wang Yi-Fang , Admovics John , Wuu Cheng-Shie
Published: August 2019

Cone beam computed tomography (CBCT) imaging has been implemented on the Leksell Gamma Knife Icon
TM
for repeated patient positioning in mask-based Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy of the CBCT-based patient positioning on the Gamma Knife Icon
TM
. Two Presage phantoms of 15 cm diameter and 10 cm height were irradiated with identical shot placements on an Acoustic Neuroma target with the same prescription dose following standard mask-based treatment workflow according to two different fraction schedules: a single fraction of 7.5 Gy and 5 fractions with 1.5 Gy fraction dose. On the top and the bottom portions of each phantom, 8 single 16 mm collimator shots were delivered with maximum doses from 2 Gy to 20 Gy for dose sensitivity calibration. The irradiated Presage phantoms were scanned and analyzed using an OCTOPOUS optical CT scanner. Both the absolute dose distributions and the relative dose distributions for the Acoustic target on each phantom were compared with those from the treatment planning system. The relative dose distribution from the single fraction irradiation agrees better with the planning system than the 5 fraction irradiation, indicating noticeable change in the dose distribution caused by the phantom positioning/repositioning process. No difference between the absolute dose distributions from the two phantoms could be identified because of the large uncertainty in the experiment data.
Initial performance evaluation of a 3D gel dosimeter based on modified tetrazolium compounds
Authors: Hazarika Rubin , Penev Kalin I , Mequanint Kibret , Jordan Kevin
Published: August 2019

Tetrazolium-based 3D gellan gum gel dosimeters have been reported previously and tested at several sites. They show no image diffusion and excellent stability; however, the dose sensitivity of the current commercial product, ClearView™, is relatively low for routine clinical applications. Here we report initial testing of a second generation product with increased sensitivity and retained non-diffusive properties. This formulation has a 25% increase in sensitivity relative to ClearView™. However, the sample has a higher initial attenuation and the background attenuation increases faster than ClearView™. The composition was tested in a 1-liter sealed container using a 2x2 cm, 6MV, x-ray beam, and show agreement between Monte Carlo simulation and measurements.
Evaporation and diffusion of chloroform with the deformable FlexyDos3D radiation dosimeter
Authors: Wheatley M J , Booth J T , De Deene Y
Published: August 2019

Chloroform in the FlexyDos3D dosimeter acts as a radical initiator which brings about the colour change of the dosimeter when the radicals react with the leucomalachite green. However, the volatility of the chloroform likely results in a rapid loss of chloroform from the dosimeter. Gravimetric analysis and NMR diffusion-ordered coherence spectroscopy were used to measure the diffusion and evaporation rates of chloroform from the dosimeter and found that both rates were both significantly large resulting in a rapid loss of chloroform. Dose maps of irradiated phantoms aged for different times found a significant difference in the dose measurements of the dosimeter, likely a result of the different chloroform concentrations within the dosimeters.
Radiation induced degradation of rhodamine 6G and 7-Diethylamino-4-methylcoumarin in nano-clay gel for use in dosimeter
Authors: Maeyama T. , Mochizuki A. , Takanashi T.
Published: August 2019

Rhodamine 6G (R6G) and 7-diethylamino-4-methylcoumarin (7D4MC) were applied to a nanoclay gel dosimeter based on radiation-induced degradation. The radiological properties were evaluated under X-ray irradiation. The fluorescent dyes showed linear degradation with an increase in dose. In addition, the distribution of fluorescence induced by inhomogeneous irradiation was maintained for two months and a suppressed diffusion of the fluorescent dyes in the gel matrix was observed.
Gel dosimetry measurement of dose enhancement bismuth-based nanoparticles in radiation therapy
Authors: Rajaee Azimeh , Wang Shi , Zhao Lingyun , Liu Yaqiang
Published: August 2019

Recently bismuth-based nanoparticles as a promising radiosensitizer have drawn great attention in radiation therapy. To prove physical dose enhancement effect of the nanoparticles, gel dosimeters can be considered as an ideal method. This study aims to prove the applicability of bismuth ferrite nanoparticles as a magnetic localized dose enhancement agent by gel dosimetry method. Bismuth ferrite nanoparticle was synthesized by the conventional sol-gel method. Then we investigated dose enhancement property of the nanoparticles with gel dosimetry. MAGIC Polymer Gel dosimeters with nanoparticles were prepared and irradiated. According to gel dosimetry assay, for 0.5 mg/ml concentration of bismuth ferrite nanoparticles dose enhancement factor were obtained as 2 and 1.6 at 160 keV and average energy of 380 keV, respectively. Moreover, radiosensitiser effect of bismuth ferrite nanoparticles in presence of a low dose rate brachytherapy source (125-I) was investigated by Monte Carlo method. Whereas bismuth ferrite nanoparticles have magnetic property, we made a biodegradable spacer (fiducial) brachytherapy loaded with the nanoparticles for delivering nanoparticles and drug by applying an external magnetic field.
Teaching the principles of X-ray CT and SPECT using optical CT, glowsticks and a scaled anthropomorphic phantom
Authors: De Deene Yves
Published: August 2019

Teaching demonstrations of computerized tomography (CT) and Single-Photon Emission Tomography (SPECT) to biomedical engineering and medical physics students is hampered by a limited accessibility to clinical scanners, especially during day time. The use of ionizing radiation and radioactive sources in X-ray CT and SPECT further complicates the design of a teaching laboratory session. We here propose an inexpensive and safe educational demonstration of CT and SPECT on an anthropomorphic phantom whereby a visible light source serves as source and a CCD camera serves as detector. The equivalent of a SPECT radionuclide in optical CT scanning is a chemiluminescent material which can be obtained relatively inexpensive in the form of party glow sticks. The proposed teaching tool comprises several learning outcomes such as hands-on construction of the scanner, the acquisition of images and image reconstruction. Also, different imaging artefacts can be simulated and investigated.
A sliding-window approach for improved VMAT dose calculation accuracy
Authors: Alahmad Haitham N , Park Ji-Yeon , Potter Nicholas J , Lu Bo , Yan Guanghua , Liu Chihray , Li Jonathan G
Published: August 2019

A sliding-window (SW) methodology for VMAT dose calculation was developed. For any two adjacent VMAT control points (CPs) n and n+1, the dose distribution was approximated by a 2-CP SW IMRT beam with the starting MLC positions at CP n and ending MLC positions at CP n+1, with the gantry angle fixed in the middle of the two VMAT CPs. Therefore, for any VMAT beam with N CPs, the dose is calculated with N-1 SW beams. VMAT plans were generated for ten patients in Pinnacle using 4° gantry spacing. For each patient, the VMAT plan was converted to a SW IMRT plan and dose was re-calculated. Another VMAT plan, with 1° gantry spacing, was created by interpolating the original VMAT beam. The original plans were delivered on an Elekta Versa HD and measured with Mapcheck2 using an in-house developed subarc method. For both the isodose distribution and DVH, there were significant differences between the original VMAT plan and either the SW or the interpolated plan. However, they were indistinguishable between the SW and interpolated plans. The average passing rate between the original VMAT plan and measurements was 84%. For both the interpolated and SW plans, the average passing rate was 96%. We conclude that the proposed SW approach improves VMAT dose calculation accuracy without increase in dose calculation time.
Digital methods of managing investment and construction projects as a factor of sustainable territorial development
Authors: Dmitriev A N , Yu Kallaur G , Papikian L M
Published: August 2019

Currently, the documents of strategic planning in Russia prescribe the innovative economic development based on digital technologies. In construction, which is a material and technical basis for the development of other industries, the question of introducing and using information-modeling technology is of paramount importance. This fact determined the subject of this study. The relevance of the topic is dictated by the search for ways of sustainable economic development with regard to the sectoral and territorial aspects based on the effective implementation of investment-and-construction projects in the emerging digital environment. The authors use analytical and comparative methods to summarize the present international experience in the development of construction in the context of application of information modeling technologies. Based on that, they also consider the basic principles of economic development in the context of using digital methods as the main factor of sustainable territorial development. As a result, proposals were formulated for integrating the information modeling of capital construction facilities into the project management system at various levels of economic decision making: federal, regional, municipal, and business. Through the example of Moscow, the territorial-sectoral structure of managing investment and construction projects was considered. The authors substantiated their conclusions on the priority measures for the development of the innovation system in construction for the sustainable territorial development.
Evaluation of the use of hunting potential in the Republic of Buryatia
Authors: Osodoev P V
Published: August 2019

The article considers the current state of hunting resources use in the Republic of Buryatia. The dynamics of abundance and production of the main species of commercial animals from 1990 to 2017 is analyzed. The low demand for some species leads to underutilization of the available potential. The greatest efficiency of hunting resources use is observed in relation to sable and musk deer. On the basis of data on the number, production of hunting animals and average market prices for products, the potential and annual use of hunting resources have been estimated. Hunting farms in the region are characterized by an extensive production method, based on the provision of lands for hunters on the rental basis. Share of expenses for the development of infrastructure and the implementation of biotechnical measures in hunting farms expenditure pattern is insignificant. The main directions of improvement of hunting resources use effectiveness are the measures aimed at increasing the number of hunting animals (biotechnical measures), combating illegal hunting, regulating the number of large predators. The use of hunting areas for recreational purposes and development of hunting tourism is promising.
The dynamics of biogenic elements in the ecosystem of Lake Arakhley (Eastern Transbaikal Region)
Authors: Matveeva M O , Ts Tsybekmitova G
Published: August 2019

This study presents the interannual dynamics of biogenic elements (nitrogen and phosphorus) in Lake Arakhley and compares functioning values of the water ecosystem within different types of intra-annual (seasonal) dynamics of the content of biogenic elements and organic matter in low water years and high water years. The research shows tendencies of increasing and decreasing contents of nitrogen and phosphorus. In low water years, organic matter is autochtonous, whereas in high water years its origin is allochtonous. The concentrations of biogenic elements do not exceed the values of maximum permissible concentration in fishery waters which means that eutrophication has not started. It was found that the dynamics of the content of nitrogen and phosphorus is determined by change in abiotic conditions and rate of biochemical and biological processes. The findings provide better understanding how mesotrophic lakes function.
Aromatic polybenzimidazoles from diamide and diamines
Authors: Ch Kholkhoev B , Burdukovskii V F
Published: August 2019

Aromatic polybenzimidazoles were obtained by oxidative dehydrocyclization of polyamidines, which were originally synthesized through polycondensation of 4,4’-oxybis(benzoic acid) diamide and diamines in Eaton’s reagent. The transformation was performed in solution using hydrogen peroxide or sodium hypochlorite as oxidants. It was found that the degree of conversion was not noticeably influenced by the polymer concentration in solution and by its molecular weight, whereas the oxidant content exerted appreciable influence. Under the optimal reaction conditions degree of cyclization reaches 95%. The viscosity characteristics of polybenzimidazoles suggest that the transformation of polyamidines is not accompanied by a change in their molecular weights.
K5InHf(MoO4)6: A solid state conductor
Authors: Grossman V G , Bazarov B G , Bazarova J G
Published: August 2019

Potassium indium hafnium molybdate of composition K5InHf(MoO4)6 has been studied by powder X-ray diffraction, differential scanning calorimetric (DSC) analysis and impedance spectroscopy. The compound has high ion conductivity. The high conductivity of K5InHf(MoO4)6 allows us to consider it as a promising solid electrolyte.
Recyclability of plastic waste extracted from electrical devices
Authors: Turku I , Kärki T
Published: August 2019

The mechanical recyclability of acrylonitrile butadiene styrene, high impact polystyrene, polycarbonate and polypropylene extracted from electric equipment waste was studied. The secondary raw material was tested on a broad range of working characteristics, such as melt flow index, thermal properties as well as tensile properties of injection molded samples were detected. Parameters were compared with parameters of unprocessed counterparts presented in the literature.
The biocompatibility of titanium alloy or stainless steel internal fixation material combined with anti-tuberculosis drug sustained-release carrier
Authors: Wang Na , Guo Shaoning , Yang Kang , Wang Jinguo
Published: August 2019

The purpose of this paper is to summarize the treatment of characteristics of bone tuberculosis with titanium alloy or stainless steel internal fixation devices combined with antituberculosis sustained-release materials. A search of literature on the implantation of titanium alloy or stainless steel internal fixation devices combined with anti-tuberculosis sustained-release materials for bone tuberculosis from 1995 to 2019 was performed using PubMed and Web of Science databases. Local sustained-release anti-tuberculosis drugs have been applied in surgical treatment of bone and joint tuberculosis. It can reduce the adverse reactions of systemic administration of a number of anti-tuberculosis drugs in patients with bone tuberculosis and continuously achieve the local effective anti-tuberculosis effect. At present, there are many kinds of materials used in drug sustained-release materials, each of which has its own advantages and disadvantages. It is difficult to achieve the ideal effect of antituberculosis and bone repair. Different materials can be used together to make up the disadvantages for each other. The further progress towards ideal biological materials can be achieved. It may be the developing trend of clinical application of multi-material composite as sustained-release carrier against tuberculosis.
Development and application of an anticorrosion type water release agent
Authors: Xing Juxiang , Xiong Long , Li Xing
Published: August 2019

Water based release agents have attracted widely attention in recent years due to their advantages, such as environmental and convenience. However, during the application process, the resistance to the steel mould is not obvious, and the concrete surface is easy to rust, which affects the appearance of the concrete surface. The application of aluminium mould can’t solve the problem of bubble and surface ash. The ZJTM anticorrosion type water release agent developed in this paper can effectively solve the corrosion of the concrete surface, bubble and surface ash, and the effect is remarkable in all kinds of engineering.
Synthesis of Ag doped SiO2-TiO2 aerogels with nano-sized microcrystalline anatase structure through IL control
Authors: Dai Hongyi , Jun Zhao , Yin Yuxin , Shao Guolin , Yu Chunling
Published: August 2019

In this paper, Ag doped SiO2-TiO2 aerogels with nano-sized microcrystalline anatase structure through a sol-gel way, ionic liquid(IL), 1 – butyl-3-methylimidazole bromide ([bmim]Br), is used as a structure control agent. The catalysts were characterized by SEM, XRD and nitrogen adsorption-desorption isotherms (BET analyses). The photocatalytic activities were investigated by degration of active brilliant blue under UV-light. It was demonstrated that IL facilitate the formation of mesoporous and anatase microcrystalline structure at around ambient condition, without calcination. Both at sol-step and gel-step, the concentration of IL aqueous solution prominently effected on the structure properties of catalysts. Surface area, crystalline grain dimension and mecroporous structure all played important roles in the degradation reactions. The catalyst with 1/10 Si/Ti ratio, 385.2 m2g-1surface area and 6.2nm crystalline grian size, showed excellent photocatalytic degradation rate up to 99.7%.
A-02 Baseline Symptom Reporting Scores Vary Between International and Domestic Athletes as Measured by SCAT-5 and ImPACT
Authors: Norheim N , Kissinger-Knox A , Grueninger K , Roccaforte A , LoGalbo A , Webbe F
Published: August 2019

Objective

Prior research has not evaluated symptom-reporting differences between international and domestic athletes for baseline concussion symptoms. Since universities enroll both, it is important to consider differences for interpretation of post-trauma assessments. This study compared symptom endorsements between international and domestic athletes utilizing the Sport Concussion Assessment Tool-5th Edition (SCAT5) and Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT).

Method

622 domestic collegiate athletes, aged 17-25 years (M = 19.29, SD = 1.44; 65% male), and 167 international collegiate athletes, aged 17-24 (M = 20.27, SD = 1.61; 62% male) were administered the SCAT5 and ImPACT. All symptoms were compared.

Results

International participants (M = 3.46; SD = 3.99) reported significantly more symptoms, U = 42561, p < 0.001 (Mann-Whitney U Test), on the SCAT5 compared to domestic participants (M = 2.43; SD = 3.20), and at a greater severity, U = 43404, p = 0.001, among international participants (M = 5.04; SD = 7.27) compared to domestic participants (M = 3.70; SD = 5.54). Of the 22 SCAT5 symptoms, 9 were endorsed more frequently by international students. International participants (M = 4.95; SD = 7.57) also reported significantly more symptoms, U = 43514, p = 0.001, on the ImPACT compared to domestic participants (M = 3.18; SD = 5.35). Of the 22 ImPACT symptoms, 12 were endorsed more frequently by international students and 2 by domestic.

Conclusions

International athletes report significantly more symptoms and at a greater severity on ImPACT and SCAT5 compared to domestic athletes. Differences did not appear related to travel and fatigue such as sensitivity to light and noise, difficulty concentrating, and feeling more emotional. Over 20,000 international student-athletes are enrolled in the NCAA, it is important to note differences observed in symptom reporting for appropriate baseline evaluation (NCAA, 2019).
A-09 Attention in individuals with Heroin dependence measured by digit span versus continuous performance test
Authors: Sarkissians S , Hauson A , Stelmach N , Walker A , Pollard A , Barlet B , Hall M , Wollman S
Published: August 2019

Objective

Heroin dependent individuals appear to have significant deficits in attention which can be assessed using digit span forward (DSF) or the continuous performance test (CPT). The current meta-analysis examined differences between DSF and CPT results in studies of heroin dependent participants.

Data selection

Two researchers independently searched nine databases (e.g., PsycINFO, Pubmed, ProceedingsFirst), extracted required data, and calculated effect sizes. Inclusion criteria identified studies that had (a) compared heroin-dependent groups to healthy controls and (b) matched groups on either age, education, or IQ (at least 2 out of 3). Studies were excluded if participants were reported to have Axis I diagnoses (other than heroin dependence) or comorbidities known to impact neuropsychological functioning. Ten articles were coded and analyzed for the current study.

Data synthesis

When examined together, DSF and CPT evidenced a moderate and statistically significant effect size estimate (g = 0.614, p = .002). Subgroup analysis did not reveal statistically significant differences between the two groups (Q-Between = 0.228, p = 0.633). The effect size for DSF was g = 0.535 (p = 0.001) and for CPT was g = 0.774 (p = 0.104). The heterogeneity of DSF was in the moderate range, I2 = 71.291%, p = 0.002 while the heterogeneity of CPT was in the large range I2 = 97.863%, p = 0.001.

Conclusion

Heroin dependent individuals appear to demonstrate similarly poor performance on DSF and CPT. Assuming that both tests measure the same construct, both appear to be sensitive to the effect of Heroin on attention.
A-14 An Updated Item Response Analysis of the Halstead Category Test
Authors: Goette W , Schmitt A , Nici J
Published: August 2019

Objective

To identify item parameter estimates for the Halstead Category Test (HCT). Previous item response analyses have been conducted on the HCT but without implementing item response theory methods.

Method

Data were collected from a diagnostically heterogenous sample of 211 adults (110 males, 101 females) referred for neuropsychological evaluation. The sample had an average educational attainment of 14.18 years (SD = 3.05 years) and an average age of 59.75 years (SD = 18.28). Responses from items on Subtests III-VII were dichotomously coded (0 = incorrect, 1 = correct). A two-parameter, hierarchical, logistic item response model was fit to the data using code in Stan, which uses an adaptive variant of Hamiltonian Monte Carlo.

Results

The model converged appropriately with posterior estimates of item parameters all demonstrating adequate effective sample sizes (min. = 3485.74) and Rhat (max. = 1.002). The range of posterior difficulty estimates follows: -1.06-2.07 (III), -1.67-1.92 (IV), -3.80-2.62 (V), -2.35-4.38 (VI), and -2.28-1.80 (VII). The range of posterior discrimination estimates follows: 0.20-5.41 (III), 0.35-8.17 (IV), 0.11-4.14 (V), 0.69-5.88 (VI), and 0.53-2.83 (VII).

Conclusions

The HCT demonstrates a wide range of item difficulties with few items being excessively difficult, though some in this range were identified in Subtest VI. Ranges for item discriminations are also wide with some estimates returning high estimates, which may be related to the smaller sample size for a two-parameter model or may be due to less-than-ideal item functioning. These findings support the longstanding sensitivity of the HCT to a variety of neurological conditions and across the severity spectrum.
A-15 Examining the Construct Validity of the Halstead Category Test - Computer Version: A Confirmatory Factor Analysis
Authors: Goette W , Schmitt A , Nici J
Published: August 2019

Objective

To examine evidence of construct validity for the Halstead Category Test – Computer Version (HCT-CV). Previous factor analyses on the HCT generally found the following structure: a Counting factor comprised of Subtests I and II; a Spatial Reasoning factor of Subtests III, IV, and VII; and a Proportional Reasoning factor of Subtests V and VI.

Method

Data were collected from a diagnostically heterogeneous sample of 105 adults (56 males, 49 females) referred for neuropsychological evaluation who completed the HCT-CV. The sample had an average educational attainment of 14.37 years (SD = 2.98 years) and an average age of 62.30 years (SD = 17.53). The total number of errors made on each of the seven HCT subtests were computed for each participant, and these data were used to complete a regularized confirmatory factor analysis based on the identified factor structure of the HCT.

Results

The confirmatory factor analysis converged normally. The model fitting the HCT factor structure demonstrated excellent overall fit to the HCT-CV data: χ2(11) = 12.20, p = .35; RMSEA = 0.03 (95% CI: 0.00 to 0.11); SRMR = 0.03; CFI = 1.00; TLI = 0.99. Analysis of the residuals and modification indexes further confirmed the excellent model fit.

Conclusions

The HCT-CV demonstrates what appears to be an unchanged factor structure to the HCT. This finding supports the computerized version construct validity as being seemingly unchanged from that of the slide projector version. This model fit may be viewed as promising for the comparability between the original version and the computerized version.
B-71 The Effect of Bilingualism on Verbal and Design Fluency Performance in Traumatic Brain Injury Survivors and Healthy Adults
Authors: Bueno A , Lopez Hernandez W , Litvin P , Knight J , McElwee C , Cervantes R , Rugh-Fraser R , Arzuyan A , Bichlmeier A , Fatoorechi SMangassarian S , Hardy D , Vespa P , Plurad D , Hovda D , Woo E , Fuster J , Budding D , Wright M
Published: August 2019

Objective

Traumatic brain injury (TBI) impacts neurocognitive function. Language is also known to influence test performances. We examined the relationship between TBI and monolingualism/bilingualism on verbal and design fluency tests.

Method

The sample (N = 74) consisted of 33 healthy controls (18 bilingual; 15 monolingual), 15 acute TBI participants (6 bilingual; 9 monolingual), and 26 chronic TBI participants (15 bilingual; 11 monolingual). Acute TBI participants were tested 6 months post-injury and chronic TBI participants were tested 12 months or more post-injury. The Delis-Kaplan Executive Function System Letter Fluency (DKEFS-LF), Category Fluency (DKEFS-CF), Category Switching Fluency (DKEFS-CSF), and global verbal fluency composite (DKEFS-GVF) scores assessed verbal fluency; DKEFS fill-dots (DKEFS-FD), empty dots (DFEFS-ED), dot switching (DKEFS-DS), and global design fluency composite (DKEFS-GDF) scores assessed design fluency; and global verbal and non-verbal fluency composite (DKEFS-GF) assessed overall fluency. 3X2 ANOVAs were conducted to evaluate the effect of monolingualism/bilingualism on fluency performance in TBI and controls.

Results

The groups (control and TBI groups) differed for DKEFS-LF, p = .048, ηp² = .09, DKEFS-CF, p = .000, ηp² = .21, DKEFS-GVF, p = .004, ηp² = .15, DKEFS-ED, p = .008, ηp² = .13, DKEFS-GF, p = .001, ηp² = .20, with controls outperforming TBI groups on the DKEFS-CF, DKEFS-GVF, and DKEFS-GF. Furthermore, controls outperformed acute TBI participants on the DKEFS-LF and DKEFS-ED. Main effects were found for bilingualism/monolingualism on DKEFS-CF, p = .035, ηp² = .06, with bilinguals outperforming monolinguals. No interactions were found.

Conclusion

The TBI group had poor verbal and design fluency in contrast controls. Unexpectedly, bilinguals outperformed monolinguals on a task of verbal category fluency. Revealing that in the present study bilinguals have better semantic verbal fluency abilities.
B-73 The Relationship Between Subjective and Objective Disinhibition in Mild Traumatic Brain Injury
Authors: Holiday K , Clark A , Sorg S , Merritt V , Nakhla M , Delano-Wood L , Schiehser D
Published: August 2019

Objective

Veterans with mild traumatic brain injury (mTBI) frequently report cognitive difficulties, though these are not always supported by objective neuropsychological testing. The current study compared mTBI Veterans with subjective disinhibition to Veteran Controls (VC) on an objective response inhibition task while controlling for depression.

Methods

53 mTBI Veterans and 31 VC with optimal effort completed a go/no-go response inhibition (RI) task and measures of subjective disinhibition (Frontal Systems Executive Behavior scale) and depression (Beck Depression Inventory-II). ANCOVAs compared RI performances of VC without cognitive complaints to (1) the total sample of mTBI Veterans and (2) to mTBI Veterans with (t-score>60; mTBI+disinhibition; n = 23) and without (t-score < 60; mTBI-disinhibition; n = 30) subjective complaints of disinhibition.

Results

Relative to the VC group, the mTBI Veterans endorsed significantly greater depressive symptoms (p < .001). No significant differences in RI performance were observed when the total mTBI sample was compared to VC. However, in the three group analysis, there was a significant effect of group (p = .002) controlling for depression (p = .396). Post-hoc analyses revealed the mTBI+disinhibition group performed significantly worse than the mTBI-disinhibition (p < .001) and VC (p < .001) groups; no significance differences in RI performance were observed between the mTBI-disinhibition and VC groups (p = .914).

Conclusions

While the larger mTBI group did not differ from VC on RI performance, mTBI Veterans with subjective disinhibition complaints evidenced poorer objective RI. Findings therefore suggest that Veterans with elevated subjective complaints may be at risk for experiencing objective cognitive difficulties. Future research is needed to elucidate the neural underpinnings of these group differences as well as clinical outcomes.
C-02 An Unbiased Biomarker Approach to Neuropsychological, Behavioral, and Psychiatric Symptoms in a Mixed Clinical Sample
Authors: Hawley N , Bennett L , Ritter A
Published: August 2019

Objective

Suspected Non-Alzheimer’s Pathology (SNAPs) are individuals who present with a cognitive syndrome meeting clinical criteria for Alzheimer’s disease (AD) but are found to lack underlying AD pathology. Current clinical criteria for AD lack specificity in predicting underlying neurodegenerative pathology. With the advent of amyloid positron emission tomography (PET) the presence of amyloid pathology can now be identified in vivo. Using a biomarker-based approach, we aimed to characterize the neuropsychological, behavioral, and psychiatric profile of SNAPs in contrast to those with AD pathology (APs).

Method

76 individuals (26 amyloid-negative [SNAPs], 50 amyloid- positive [APs]) completed neuropsychological testing and a PET amyloid scan as a part of a longitudinal observational study at the Cleveland Clinic LRCBH. Individuals meeting NIA-A criteria for MCI or mild AD with a Clinical Dementia Rating score of .05 -1 were included. Amyloid status was determined via clinical read of two clinicians trained in reading amyloid scans (neuroradiologist and neuropsychiatrist). Independent samples t tests assessed group differences between SNAPs and APs across cognitive, behavioral, and psychiatric measures.

Results

Mini-Mental State Examination scores were equivalent between SNAPs and APs. SNAPs performed significantly better on measures of verbal and nonverbal memory, set-shifting, and semantic fluency, as well as aspects of processing speed and working memory (all p’s < .05). Additionally, SNAPs endorsed more RBD symptoms (p < .05). No significant group differences were observed across neuropsychiatric or functional measures.

Conclusion(s)

Differences in an individual’s neuropsychological, behavioral, and psychiatric profile in consideration with a biomarker approach may provide key insights and afford greater diagnostic clarity.
C-05 Concordance of Functional and Neuropsychological Performance among Hispanics versus White Non- Hispanics
Authors: Chirinos C , Garcia P , Duara R , Loewenstein D , Robayo C , Greig-Custo M , Curiel Cid R , Rosselli M , Rodriguez M
Published: August 2019

Objective

Racial/ethnic disparities in cognitive performance among older adults have been previously identified. This study’s aim was to examine the cognitive performance between diverse Hispanic and White non-Hispanic (WNH) older adults with similar functional performance.

Method

Groups were stratified by Clinical Dementia Rating scale (CDR) global score, as follows: (1) CDR score = 0 (n = 77; 70.1% female; Mean ± SD age = 70.9± 6.3 yrs; education = 17.4±9.9 yrs; MMSE = 28.95± 1.48); (2) CDR score = 0.5 (n = 179; 58.1% female; age = 74.0± 8.1 yrs; education = 16.0 ± 9.5 yrs; MMSE = 27.50 ± 2.5); (3) CDR Score = 1.0 (n = 41; 61% female; age = 73.7 ± 9.7 yrs; education = 16.7 ± 13.6 yrs; MMSE = 23.2 ± 3.8). A series of One-Way Analysis of Covariance (ANCOVA) were conducted comparing Hispanic to WNH, with age and education as covariates.

Results

Among the CDR = 0 group, WNH performed significantly better than Hispanics on Trails-A [F(1,69) = 8.59, p < .01], Trails B [F(1,69)=4.166, p < .05], COWAT [F(1,73)=14.79, p < .001], and Category Fluency [F(1,73)=9.91, p < .01]; findings were not significant for logical memory (p=.157), or HVLT (p=.494) delayed. Among participants with CDR of 0.5, WNH performed significantly better than Hispanics on Trails B [F(1,166)=5.83, p < .05]. Among participants with CDR of 1, there were no significant differences.

Conclusion

Among older adults with similar levels of functioning, Hispanics performed worse on measures of processing speed, executive function, and verbal fluency. Future studies should evaluate the contribution of level of acculturation, social engagement and exercise to differences in cognitive scores among individuals with similar functional performance.
C-15 Serotonergic System Activity and BPSD in Alzheimer’s Disease Pathogenesis: A Systematic Review
Authors: Lennon J , Sytsma B , Mohit A , Patel S
Published: August 2019

Objective

The 5-hydroxytryptamine (5-HT) system is heavily implicated in behavioral and psychological symptoms of dementia (BPSD), with substantial bases for ongoing research in Alzheimer’s disease (AD). This system is directly tied to the hypothalamic-pituitary-adrenal axis. This systematic review aims to accomplish the following objectives: 1) introduce noteworthy BPSD found in AD; 2) synthesize research on 5-HT and BPSD in AD; 3) discuss neuropsychological sequelae of serotonergic dysregulation in AD; and, 4) report future research directions.

Data Selection

Data Selection: We conducted a literature search of the Medline, PubMed, psychINFO, and Google Scholar databases using the following keywords: Alzheimer’s*, seroton* (serotonin, serotonergic), 5-HT* (5-HTR, 5-HTT*), neuropsychology, behavior*, cogniti*. From the list of studies obtained through this search, we then employed the following inclusion criteria: 1) individuals in study had a formal diagnosis of probable or suspected AD; 2) individuals in study had not previously experienced head trauma, recurrent seizure, or other neurological insult; 3) sample did not include participants with comorbid personality disorders.

Data Synthesis

Findings suggest that serotonin’s receptors (5-HTRs), transporter (5-HTT), metabolite (5-HTP), and transporter-linked polymorphic region (5-HTTLPR) are linked to depression, anxiety, hyperactivity/impulsivity, aggression, and apathy in AD. Further, 5-HT and resultant BPSD are implicated in numerous cognitive functions including but not limited to decision-making, visual-spatial deficits, attention and vigilance, episodic memory, global cognitive function.

Conclusions

Substantial evidence exists implicating the serotonergic system in BPSD in AD. By understanding the impact of 5-HT on disease trajectory, neurocognitive functioning, and neuropsychological test performance, clinicians can ensure that appropriate recommendations are made for psychosocial and pharmacological intervention.
C-20 Cardiorespiratory Fitness Predicts Processing Speed Performance in Urban Latin Americans
Authors: Alioto A , Conde K , Salazar-Villanea M , Moncada-Jimenez J , Cahn-Weiner D , Johnson D
Published: August 2019

Objective

There is evidence that cardiorespiratory fitness (CRF) protects against age-related declines in processing speed (PS), but studies investigating older adults living in low and middle-income countries are lacking. We used data from the Epidemiology and Development of Alzheimer’s Disease (EDAD) study to investigate the role of CRF on PS in older Costa Rican adults.

Method

306 community dwelling older adults (mean age = 69) were recruited for a study on cognition and physical fitness. We used a regression model to test the association between CRF and a composite measure of PS (Digit Symbol, Trails A, Block Design, and Stroop Color Naming). Confirmatory factor analysis (CFA) with full information maximum likelihood was conducted in a nested multi-step process on subtest scores. We also compared the strength of the relationship between two measures of CRF: Maximal oxygen uptake (V02 peak) and a latent variable comprised of distance achieved during the 6-minute Walk Test and change in heart rate before and after walking (Modified 6-Minute Walk).

Results

Higher CRF was significantly associated with PS, and the association remained significant after controlling for age and sex (B = 0.21; p < .001). The strength of the relationship between two measures of CRF was very high, suggesting equivalence of these indices.

Conclusions

CRF and PS are clinically meaningful therapeutic targets for future prevention trials in Latin America. The modified 6-Minute Walk is an efficient approximation of the gold standard CRF measurement. The cognitive benefits of CRF should be compared to other lifestyle interventions (e.g., diet) to determine the active components of cognitive improvement.
C-28 Raven’s Progressive Matrices: Validation of a Short Form
Authors: Irrgang M , Dorenkamp M , Reohr P , Vik P
Published: August 2019

Objective

The Raven’s Standard Progressive Matrices (RSPM) is a 60-item measure of non-verbal abstract reasoning. The length of the RSPM presents a potential barrier to its use. Consequently, Bilker et al. (2012) identified a 9-item short form (RSPM-SF). The purpose of this study is to (a) provide descriptive statistics for the RSPM-SF from a non-patient sample, and (b) validate the RSPM-SF by exploring correlations with congruent and divergent cognitive measures.

Method

Twenty men and 23 women, aged 55 to 83 (M = 67.79), completed a test battery that included the SPM-SF and global, memory, verbal, and executive measures.

Results

The mean score for the RSPM-SF was 4.40 (median = 4, mode = 4, SD = 1.92). RSPM-SF correlated best with the Montreal Cognitive Assessment (r = .548, CI: .297 to .729) and poorest with letter fluency (r = .065, CI: -.456 to .127). Correlations with executive measures ranged from a low of .308 (Tower Test; CI: .019 to .549) to a high of .470 (Trail Making Test Part-B; CI: .197 to .675). The average correlation with executive scores was .412. Average correlation with learning (both verbal and non-verbal) was .435, and with recall was .296.

Conclusions

RSPM historically was viewed as a non-verbal global estimate of cognitive ability. Present findings support using the RSPM-SF as a global measure, as it correlated well with both verbal and nonverbal, and executive and memory tests. Descriptive data suggested that the RSPM-SF items ranged from easy to difficult.
C-38 Telehealth Dementia Management in a Memory Care Unit: Survey Response Rates and Quality of Life
Authors: Pizer J , LaRoche A , Sawyer R , Arredondo B , Mizuki B , Knoop C
Published: August 2019

This feasibility study assessed changes in patient, staff, and family member ratings over time in a program using technology in patient care on an inpatient dementia unit in a nursing home.

Method

Dementia patients [N = 17; 50% Female; Age M (SD) = 84.56 (7.12); CDR M (SD) = 2.24 (5.17); MoCA M (SD) = 6.67 (.75)], caregivers (N = 17), and staff (N = 27) at a locked memory unit of a long-term care facility in the southern U.S. consented and enrolled in an individualized care program that implemented telehealth visits between a neuropsychologist and residents with staff. The start and end dates of the group varied due to new admissions and deaths. A feasibility study using a repeated measures design was conducted with monthly data collected from questionnaires (Quality of Life (QoL), Professional Care Team Burden (PCTB) Scale, and Zarit Caregiver Burden Inventory).

Results

QoL in residents as rated by staff was stable over a five-month interval [Baseline M (SD) = 37.94 (7.28); Month-5 M (SD) = 37.13(5.96), p = 0.98]. PCTB and Zarit responses were adequate at baseline (96.3% and 94.4%); however, due to poor response rates at Month 5 (14.3% and 27.2%), comparisons weren’t possible.

Conclusion

Changes in patient quality of life were not found over a five-month period. However, due to the severity and progression of dementia, a neutral finding may be positive. Anecdotally, perceptions of the program were positive. However, due to low survey response rates, we cannot accurately translate the benefits to the staff and family. Future studies should assess improving response rate or alternate forms of data collection. Generalizability is limited by size and setting.
C-43 The Relation Between Executive Functioning and Fluid Reasoning Performance in Children with Attention-Deficit/Hyperactivity Disorder
Authors: Coultis N , Brown A , Heideman E
Published: August 2019

Objective

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that affects about 5% of school-aged children.4 Fluid reasoning (FR) tasks assess one’s ability to detect underlying conceptual relationships and use reasoning to identify and apply rules to problem solve.4 Previous research has demonstrated that children with ADHD perform more poorly in FR, though the mechanism behind this is unclear.3,4 The literature suggests that FR is reliant on executive functioning skills such as inhibitory control, working memory, and planning.1,4 Therefore, this study examines how performance on FR from the Wechsler Intelligence Scale for Children (WISC-V) is related to measures of executive functioning (EF) and attention in children with ADHD.

Method

Participants were children aged 8 to 16-years with ADHD (N = 75) referred for neuropsychological testing. Participant demographics: males (N = 50, 65.8%), females (N = 26, 34.2%); African American (5.3%), Asian (1.3%), Caucasian (52.6%), Other (39.5%). Measures included the WISC-V Fluid Reasoning Index (FRI), Delis-Kaplan Executive Function System (DKEFS) Color Word Identification (CWI) and Tower subtests, omissions/commissions on the Conners Continuous Performance Test (CPT), and Behavior Rating Inventory of Executive Functioning (BRIEF) subscales.

Results

Bivariate correlations showed that the FRI was only significantly positively correlated with CWI Inhibition/Switching Time (r = .246, p = .047). Commission errors on the CPT approached significance (r = .217, p = .145).

Conclusion

The WISC-V FRI may be vulnerable to weaknesses in EF or behavioral control in children with ADHD and should be interpreted in that context. Findings suggest the FRI may be particularly impacted by weaknesses in inhibitory control.