Routinely reported structured data from the electronic health record (EHR) are frequently used for secondary purposes. However, it is unknown how valid routinely reported data are for reuse.This... Show moreRoutinely reported structured data from the electronic health record (EHR) are frequently used for secondary purposes. However, it is unknown how valid routinely reported data are for reuse.This study aimed to assess the validity of routinely reported Rutherford scores by clinicians as an indicator for the validity of structured data in the EHR.This observational study compared clinician-reported Rutherford scores with medical record review Rutherford scores for all visits at the vascular surgery department between April 1, 2016 and December 31, 2018. Free-text fields with clinical information for all visits were extracted for the assignment of the medical record review Rutherford score, after which the agreement with the clinician-reported Rutherford score was assessed using Fleiss' Kappa.A total of 6,633 visits were included for medical record review. Substantial agreement was shown between clinician-reported Rutherford scores and medical record review Rutherford scores for the left ( k = 0.62, confidence interval [CI]: 0.60-0.63) and right leg ( k = 0.62, CI: 0.60-0.64). This increased to the almost perfect agreement for left ( k = 0.84, CI: 0.82-0.86) and right leg ( k = 0.85, CI: 0.83-0.87), when excluding missing clinician-reported Rutherford scores. Expert's judgment was rarely required to be the deciding factor (11 out of 6,633).Substantial agreement between clinician-reported Rutherford scores and medical record review Rutherford scores was found, which could be an indicator for the validity of routinely reported data. Depending on its purpose, the secondary use of routinely collected Rutherford scores is a viable option. Show less
Ortolan, A.; Ramiro, S.; Ramonda, R.; Heijde, D. van der 2022
Objectives: The alternative ASDAS (altASDAS) is an index that can be used when patient global assessment is unavailable. Our aim was to test the truth and discrimination aspects according to... Show moreObjectives: The alternative ASDAS (altASDAS) is an index that can be used when patient global assessment is unavailable. Our aim was to test the truth and discrimination aspects according to OMERACT filter 2.0 of the altASDAS in an external cohort. Methods: Cohorts from the COAST trials of ixekizumab (COAST-V, -W, -X; 16-week primary endpoint) enrolling radiographic/non-radiographic axial SpA patients were pooled. The ASDAS [original formula with patient global assessment (PGA)] and altASDAS were calculated. Truth was assessed by agreement with the continuous ASDAS [intraclass correlation coefficients (ICCs)] and ASDAS disease activity (DA) states (weighted kappa), Bland-Altman plots [mean difference (MD) and 95% limits of agreement (LoA)] and Pearson's correlations between altASDAS/ASDAS and other constructs. Discrimination was tested by the ability of altASDAS to distinguish high/low DA according to nocturnal pain >6/10 as an external anchor and agreement (kappa) with ASDAS in major improvement (MI) and clinically important improvement (CII). Results: A total of 958 patients were included. For truth, agreement with ASDAS was very good (ICC = 0.99, kappa = 0.91), MD with ASDAS was 0.03 (95% LoA -0.31-0.24) and correlation coefficients of altASDAS with related constructs were within a prespecified 0.3-wide band around those between ASDAS and the same construct. For discrimination, the altASDAS discriminated between DA states and agreed with ASDAS response (kappa MI = 0.91, CII = 0.93). Conclusions: The altASDAS was truthful and discriminative in an external cohort and as such has been fully validated to be used in cases when PGA is unavailable. Show less
Luppino, F.S.; Hollander-Gijsman, M.E. den; Dekker, F.W.; Bartlema, K.A.; Diepen, M. van 2022
Skiing and snowboarding are both popular recreational alpine sports, with substantial injury risk of variable severity. Although skills level has repeatedly been associated with injury risk, a... Show moreSkiing and snowboarding are both popular recreational alpine sports, with substantial injury risk of variable severity. Although skills level has repeatedly been associated with injury risk, a validated measure to accurately estimate the actual skills level without objective assessment is missing. This study aimed to develop a practical validated instrument, to better estimate the actual skills level of recreational skiers, based on the criteria of the Dutch Skiing Federation (DSF), and covering five different skill domains. A sample of Dutch recreational skiers (n = 84) was asked to fill in a questionnaire reflecting seven, a priori chosen predictors by expert opinion, to ski downhill and to be objectively evaluated by expert assessors. The instrument was developed to have a multidimensional character and was validated according to the TRIPOD guideline (Transparent reporting of a multivariable prediction model for individual prognosis or diagnosis). The sample reported an overall incorrect self-reported estimation of their skills, compared with the observed skill score. The instrument showed good calibration and underwent multiple validation methods. The estimated skills score showed to be closer to the observed scores, than self-reportage. Our study provides a practical, multidimensional, and validated instrument to estimate the actual skills level. It proved to better reflect the actual skills levels compared with self-reportage among recreational skiers. Show less
Verkuil, Y.I.; Nicolaus, M.; Ubels, R.; Dietz, M.W.; Samplonius, J.M.; Galema, A.; ... ; Both, C. 2022
Ecological research is often hampered by the inability to quantify animal diets. Diet composition can be tracked through DNA metabarcoding of fecal samples, but whether (complex) diets can be... Show moreEcological research is often hampered by the inability to quantify animal diets. Diet composition can be tracked through DNA metabarcoding of fecal samples, but whether (complex) diets can be quantitatively determined with metabarcoding is still debated and needs validation using free-living animals. This study validates that DNA metabarcoding of feces can retrieve actual ingested taxa, and most importantly, that read numbers retrieved from sequencing can also be used to quantify the relative biomass of dietary taxa. Validation was done with the hole-nesting insectivorous Pied Flycatcher whose diet was quantified using camera footage. Size-adjusted counts of food items delivered to nestlings were used as a proxy for provided biomass of prey orders and families, and subsequently, nestling feces were assessed through DNA metabarcoding. To explore potential effects of digestion, gizzard and lower intestine samples of freshly collected birds were subjected to DNA metabarcoding. For metabarcoding with Cytochrome Oxidase subunit I (COI), we modified published invertebrate COI primers LCO1490 and HCO1777, which reduced host reads to 0.03%, and amplified Arachnida DNA without significant changing the recovery of other arthropod taxa. DNA metabarcoding retrieved all commonly camera-recorded taxa. Overall, and in each replicate year (N = 3), the relative scaled biomass of prey taxa and COI read numbers correlated at R = .85 (95CI:0.68-0.94) at order level and at R = .75 (CI:0.67-0.82) at family level. Similarity in arthropod community composition between gizzard and intestines suggested limited digestive bias. This DNA metabarcoding validation demonstrates that quantitative analyses of arthropod diet is possible. We discuss the ecological applications for insectivorous birds. Show less
Biewenga, M.; Verhelst, X.P.D.M.J.; Baven-Pronk, M.A.M.C.; Putter, H.; Berg, A.P. van den; Nieuwkerk, K.C.M.J. van; ... ; Dutch Autoimmune Hepatitis Study G 2021
Background No prognostic score is currently available for long-term survival in autoimmune hepatitis (AIH) patients. Objective The aim of this study was to develop and validate such a prognostic... Show moreBackground No prognostic score is currently available for long-term survival in autoimmune hepatitis (AIH) patients. Objective The aim of this study was to develop and validate such a prognostic score for AIH patients at diagnosis. Methods The prognostic score was developed using uni- & multivariate Cox regression in a 4-center Dutch cohort and validated in an independent 6-center Belgian cohort. Results In the derivation cohort of 396 patients 19 liver transplantations (LTs) and 51 deaths occurred (median follow-up 118 months; interquartile range 60-202 months). In multivariate analysis age (hazard ratio [HR] 1.045; p < 0.001), non-caucasian ethnicity (HR 1.897; p = 0.045), cirrhosis (HR 3.266; p < 0.001) and alanine aminotransferase level (HR 0.725; p = 0.003) were significant independent predictors for mortality or LT (C-statistic 0.827; 95% CI 0.790-0.864). In the validation cohort of 408 patients death or LT occurred in 78 patients during a median follow-up of 74 months (interquartile range: 25-142 months). Predicted 5-year event rate did not differ from observed event rate (high risk group 21.5% vs. 15.7% (95% CI: 6.3%-24.2%); moderate risk group 5.8% versus 4.3% (95% CI: 0.0%-9.1%); low risk group 1.9% versus 5.4% (95% CI: 0.0%-11.4%); C-statistic 0.744 [95% CI 0.644-0.844]). Conclusions A Dutch-Belgian prognostic score for long-term transplant-free survival in AIH patients at diagnosis was developed and validated. Show less
Background: The impact of precision psychiatry for clinical practice has not been systematically appraised. This study aims to provide a comprehensive review of validated prediction models to... Show moreBackground: The impact of precision psychiatry for clinical practice has not been systematically appraised. This study aims to provide a comprehensive review of validated prediction models to estimate the individual risk of being affected with a condition (diagnostic), developing outcomes (prognostic), or responding to treatments (predictive) in mental disorders. Methods: PRISMA/RIGHT/ CHARMS-compliant systematic review of the Web of Science, Cochrane Central Register of Reviews, and Ovid/PsycINFO databases from inception until July 21, 2019 (PROSPERO CRD42019155713) to identify diagnostic/prognostic/predictive prediction studies that reported individualized estimates in psychiatry and that were internally or externally validated or implemented. Random effect meta-regression analyses addressed the impact of several factors on the accuracy of prediction models. Findings: Literature search identified 584 prediction modeling studies, of which 89 were included. 10.4% of the total studies included prediction models internally validated (n = 61), 4.6% models externally validated (n = 27), and 0.2% (n = 1) models considered for implementation. Across validated prediction modeling studies (n = 88), 18.2% were diagnostic, 68.2% prognostic, and 13.6% predictive. The most frequently investigated condition was psychosis (36.4%), and the most frequently employed predictors clinical (69.5%). Unimodal compared to multimodal models (beta = .29, P = .03) and diagnostic compared to prognostic (beta = .84, p < .0001) and predictive (beta = .87, P = .002) models were associated with increased accuracy. Interpretation: To date, several validated prediction models arc available to support the diagnosis and prognosis of psychiatric conditions, in particular, psychosis, or to predict treatment response. Advancements of knowledge are limited by the lack of implementation research in real-world clinical practice. A new generation of implementation research is required to address this translational gap. Show less
The development of a non-sputum-based, point-of-care diagnostic test for tuberculosis (TB) is a priority in the global effort to combat this disease, particularly in resource-constrained settings.... Show moreThe development of a non-sputum-based, point-of-care diagnostic test for tuberculosis (TB) is a priority in the global effort to combat this disease, particularly in resource-constrained settings. Previous studies have identified host biomarker signatures which showed potential, but there is a need to validate and refine these for development as a test. We recruited 1,403 adults presenting with symptoms suggestive of pulmonary TB at primary healthcare clinics in six countries from West, East and Southern Africa. Of the study cohort, 326 were diagnosed with TB and 787 with other respiratory diseases, from whom we randomly selected 1005 participants. Using Luminex(R) technology, we measured the levels of 20 host biomarkers in serum samples which we used to evaluate the diagnostic accuracy of previously identified and novel bio-signatures. Our previously identified seven-marker bio-signature did not perform well (sensitivity: 89%, specificity: 60%). We also identified an optimal, two-marker bio-signature with a sensitivity of 94% and specificity of 69% in patients with no history of previous TB. This signature performed slightly better than C-reactive protein (CRP) alone. The cut-off value for a positive diagnosis differed for human immuno-deficiency virus (HIV)-positive and -negative individuals. Notably, we also found that no signature was able to diagnose TB adequately in patients with a prior history of the disease. We have identified a two-marker, pan-African bio-signature which is more robust than CRP alone and meets the World Health Organization (WHO) target product profile requirements for a triage test in both HIV-negative and HIV-positive individuals. This signature could be incorporated into a point-of-care device, greatly reducing the necessity for expensive confirmatory diagnostics and potentially reducing the number of cases currently lost to follow-up. It might also potentially be useful with individuals unable to provide sputum or with paucibacillary disease. We suggest that the performance of TB diagnostic signatures can be improved by incorporating the HIV-status of the patient. We further suggest that only patients who have never had TB be subjected to a triage test and that those with a history of previous TB be evaluated using more direct diagnostic techniques. Show less
Background Proton magnetic resonance spectroscopy (H-1-MRS) of the human heart is deemed to be a quantitative method to investigate myocardial metabolite content, but thorough validations of in... Show moreBackground Proton magnetic resonance spectroscopy (H-1-MRS) of the human heart is deemed to be a quantitative method to investigate myocardial metabolite content, but thorough validations of in vivo measurements against invasive techniques are lacking.Purpose To determine measurement precision and accuracy for quantifications of myocardial total creatine and triglyceride content with localized H-1-MRS.Study type Test-retest repeatability and measurement validation study.Subjects Sixteen volunteers and 22 patients scheduled for open-heart aortic valve replacement or septal myectomy.Field Strength/Sequence Prospectively ECG-triggered respiratory-gated free-breathing single-voxel point-resolved spectroscopy (PRESS) sequence at 3 T.Assessment Myocardial total creatine and triglyceride content were quantified relative to the total water content by fitting the H-1-MR spectra. Precision was assessed with measurement repeatability. Accuracy was assessed by validating in vivo H-1-MRS measurements against biochemical assays in myocardial tissue from the same subjects.Statistical Tests Intrasession and intersession repeatability was assessed using Bland-Altman analyses. Agreement between H-1-MRS measurements and biochemical assay was tested with regression analyses.Results The intersession repeatability coefficient for myocardial total creatine content was 41.8% with a mean value of 0.083% +/- 0.020% of the total water signal, and 36.7% for myocardial triglyceride content with a mean value of 0.35% +/- 0.13% of the total water signal. Ex vivo myocardial total creatine concentrations in tissue samples correlated with the in vivo myocardial total creatine content measured with H-1-MRS: n = 22, r = 0.44; P < 0.05. Likewise, ex vivo myocardial triglyceride concentrations correlated with the in vivo myocardial triglyceride content: n = 20, r = 0.50; P < 0.05.Data Conclusion We validated the use of localized H-1-MRS of the human heart at 3 T for quantitative assessments of in vivo myocardial tissue metabolite content by estimating the measurement precision and accuracy.Level of Evidence 2Technical Efficacy Stage 2 Show less
Objectives: Frozen and freeze-dried plasmas may be used for local prothrombin time system calibration, for direct international normalized ratio (INR) determination, and for quality assessment. The... Show moreObjectives: Frozen and freeze-dried plasmas may be used for local prothrombin time system calibration, for direct international normalized ratio (INR) determination, and for quality assessment. The purpose of the present study was to evaluate the usefulness of INRs assigned with various types of thromboplastins to frozen and freeze-dried pooled plasmas obtained from patients treated with vitamin K antagonists.Methods: INRs were calculated according to the international sensitivity index (ISI) model using various thromboplastins and instruments, i.e. International Standards for thromboplastin as well as six commercial reagents prepared from rabbit and bovine brain, and recombinant human tissue factor. The uncertainty of the INRs was assessed using the standard deviations of clotting times and ISI values. Commutability of the plasmas was assessed according to the approved Clinical and Laboratory Standards Institute (CISI) Guideline EP30-A. Validation of a set of six frozen plasma pools for direct INR determination was performed according to the Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis (SSC/ISTH) guidelines.Results: For all frozen and freeze-dried plasmas, the INRs calculated with bovine thromboplastin Thrombotest were lower than the INRs assigned with other thromboplastins. With a few exceptions, the frozen and freeze-dried pooled plasmas were commutable. When the set of six frozen plasma pools was used for local calibration, the analytical bias of the INR was less than +/- 10% for all commercial reagents except Thrombotest.Conclusions: Processing of fresh plasmas to prepare pooled frozen plasmas and freeze-dried plasmas may lead to different INR assignments depending on the thrombo-plastin used. Despite minor INR differences, a set of six frozen plasma pools could be used for local calibration by direct INR determination. Show less
ObjectivesThe aim of this study was to assess the reliability, dimensionality and validity of the self-report questionnaire Health-Risk Attitude Scale (HRAS-13) in a sample of the general... Show moreObjectivesThe aim of this study was to assess the reliability, dimensionality and validity of the self-report questionnaire Health-Risk Attitude Scale (HRAS-13) in a sample of the general population and a patient population.MethodsSample 1 (n = 930) was recruited from the general population aged 18-65 years in the Netherlands. Sample 2 (n = 486) was recruited from the population of knee and hip osteoarthritis patients aged 45 and over, also from the Netherlands. Reliability was assessed using Cronbach's alpha, average inter-item correlation and item-total correlations. Dimensionality was examined using confirmatory factor analysis (CFA), principal component analysis (PCA) and bifactor analysis. Validity was assessed by performing known-group analysis using ANOVA tests.ResultsCronbach's alphas of the HRAS-13 were 0.73 in sample 1 and 0.69 in sample 2. Reliability and dimensionality analyses differed slightly between the samples, and suggest that a short version of the HRAS may capture a general component of health-risk attitude. Validity assessment of known groups showed that the HRAS-13 and a likely HRAS-6 distinguished between subgroups of respondents based on most of the assessed characteristics, but not all.DiscussionThese findings are a preliminary indication that the HRAS-13 is a promising multidimensional instrument for measuring health-risk attitude. However, further research in various samples on decisions where health risks play a role is warranted to confirm the dimensionality of the HRAS-13 and the items to be retained in a full or a shorter version. Show less
Background Despite the availability of guidelines for the performance of transcatheter aortic valve implantation (TAVI), current treatment pathways vary between countries and institutions, which... Show moreBackground Despite the availability of guidelines for the performance of transcatheter aortic valve implantation (TAVI), current treatment pathways vary between countries and institutions, which impact on the mean duration of postprocedure hospitalization.Methods and Results This was a prospective, multicenter registry of 502 patients to validate the appropriateness of discharge timing after transfemoral TAVI, using prespecified risk criteria from FAST-TAVI (Feasibility and Safety of Early Discharge After Transfemoral [TF] Transcatheter Aortic Valve Implantation), based on hospital events within 1-year after discharge. The end point-a composite of all-cause mortality, vascular access-related complications, permanent pacemaker implantation, stroke, cardiac rehospitalization, kidney failure, and major bleeding-was reached in 27.0% of patients (95% CI, 23.3-31.2) within 1 year after intervention; 7.5% (95% CI, 5.5-10.2) had in-hospital complications before discharge and 19.6% (95% CI, 16.3-23.4) within 1 year after discharge. Overall mortality within 1 year after discharge was 7.3% and rates of cardiac rehospitalization 13.5%, permanent pacemaker implantation 4.2%, any stroke 1.8%, vascular-access-related complications 0.7%, life-threatening bleeding 0.7%, and kidney failure 0.4%. Composite events within 1 year after discharge were observed in 18.8% and 24.3% of patients with low risk of complications/early (<= 3 days) discharge and high risk and discharged late (>3 days) (concordant discharge), respectively. Event rate in patients with discordant discharge was 14.3% with low risk but discharged late and increased to 50.0% in patients with high risk but discharged in <= 3 days.Conclusions The FAST-TAVI risk assessment provides a tool for appropriate, risk-based discharge that was validated with the 1-year event rate after transfemoral TAVI.Registration URL: https://www.ClinicalTrials.gov; Unique identifier: NCT02404467. Show less
Objective: We aimed to validate a food-frequency questionnaire (FFQ) for Dutch pregnant women, against three 24 h-recalls and blood concentrations of B-vitamins and fatty acids, using the method of... Show moreObjective: We aimed to validate a food-frequency questionnaire (FFQ) for Dutch pregnant women, against three 24 h-recalls and blood concentrations of B-vitamins and fatty acids, using the method of triads. Methods: We included 83 pregnant women from the general population of Rotterdam, the Netherlands, at a median gestational age of 15.6 weeks. Participants completed three non-consecutive 24 h-recalls, and subsequently filled out the 293-item FFQ. Participants provided blood samples from which we analyzed serum folate and vitamin B12, as well as red blood cell folate, linoleic acid, and total saturated, monounsaturated, and polyunsaturated fatty acids. Results: Estimated energy intake did not differ between the FFQ and 24 h-recalls. Deattenuated Pearson's correlation coefficients, between energy-adjusted nutrient intake estimates from the FFQ and the 24 h-recalls, ranged from 0.41 (fat) to 0.88 (fiber) for macronutrients, and were around 0.6 for most micronutrients, except for vitamin E (0.27). Using the triad method, we obtained validity coefficients of 0.86 (95% Confidence Interval (CI) 0.36, 1.00) for serum folate, 0.86 (95% CI 0.18, 1.00) for red blood cell folate, and 1.00 (95% CI 0.42, 1.00) for vitamin B12. Validity coefficients for serum fatty acids ranged from 0.22 to 0.67. Conclusion: This FFQ is a reliable tool for estimating intake of energy, macronutrients, folate and vitamin B12 among women in mid-pregnancy. Show less
Broekhof, E.; Kouwenberg, M.; Oosterveld, P.; Frijns, J.H.M.; Rieffe, C. 2020
No assessment tools are available to measure shame and guilt in children who are deaf or hard of hearing (DHH), while these self-conscious emotions might play a role in the frequently noted social... Show moreNo assessment tools are available to measure shame and guilt in children who are deaf or hard of hearing (DHH), while these self-conscious emotions might play a role in the frequently noted social and behavioral problems in this group. Therefore, the aim of this study was to validate the Brief Shame and Guilt Questionnaire (BSGQ) in DHH children. In addition, we examined associations of shame and guilt with social anxiety, self-esteem, delinquency, and psychopathic behaviors. A sum of 225 hearing (M-age = 11.62 years) and 108 DHH (M-age = 11.82 years) participants completed the self-report BSGQ. Multigroup confirmatory factor analysis confirmed the two-factor structure (i.e., shame and guilt) of the BSGQ in the DHH group. Measurement invariance was established across both groups. However, the DHH group reported lower levels of self-conscious emotions in comparison with the hearing group. The BSGQ showed good concurrent validity, where shame was associated with higher levels of social anxiety and lower levels of self-esteem, and guilt was associated with lower levels of delinquency and psychopathic behavior in both groups. Future research should investigate the potential behavioral consequences of lower reported levels of self-conscious emotions in DHH youth. Show less
Matsuda, A.; Inoue, K.; Momiyama, M.; Kobayashi, K.; Kubota, K.; Ohkubo, T.; ... ; Yamaoka, K. 2019
The 10-item Perceived Efficacy in Patient-Physician Interactions (PEPPI-10) questionnaire was used as an indirect measure of the patients' perception of the strength of their therapeutic connection... Show moreThe 10-item Perceived Efficacy in Patient-Physician Interactions (PEPPI-10) questionnaire was used as an indirect measure of the patients' perception of the strength of their therapeutic connection with their physician. The English version of the PEPPI-10 could serve as a valuable research tool for analyzing the relationship between patient and physician. The incidence of breast cancer is amongst the highest in Japan, and Patient Reported Outcome is often used as an outcome measure for breast cancer. It is particularly important to establish a strong patient-physician interaction for patients with breast cancer, since these patients require long-term treatment. We designed the present study to assess the reliability and validity of the Japanese version of the PEPPI-10 in female Japanese breast cancer outpatients. A cross-sectional study was performed at the Saitama Cancer Center, Japan. From August 2014 to August 2015, the Japanese versions of the PEPPI-10 that measure patient-perceived self-efficacy and the Brief Illness Perception Questionnaire (BIPQ) that measure illness perception were used for 92 breast cancer patients who received outpatient chemotherapy (mean age: 52.9 years, Cancer Stage I or Stage II : 82.6%, receiving adjuvant chemotherapy: 69.6%). We found that the Japanese version of the PEPPI-10 scale had a high coefficient of internal consistency (Cronbach's a coefficient, 0.83) for reliability, and concurrent validity analysis indicated that the utility of PEPPI-10 was moderately correlated with that of the BIPQ. In conclusion, the Japanese version of the PEPPI-10 is a useful tool that can empower breast cancer outpatients during the course of their treatment. Show less
Besselaar, A.M.H.P. van den; Abdoel, C.F.; Rijn, C.J.J. van; Meer, F.J.M. van der; Cobbaert, C.M. 2019
Neurological disorders may impair various aspects of walking ability that are needed for safe and independent walking. A comprehensive assessment addressing the key components of walking ability... Show moreNeurological disorders may impair various aspects of walking ability that are needed for safe and independent walking. A comprehensive assessment addressing the key components of walking ability may help to tailor management strategies to the individual needs of each patient. The aspect of walking adaptability is usually not assessed in clinical tests, but seems important for safe walking and is related to fall risk. The Interactive Walkway is a promising, unobtrusive, low-cost and comprehensive assessment tool of walking ability in daily practice. It is a walkway instrumented with an integrated multi-Kinect v2 set-up for markerless registration of 3D full-body kinematics. Besides performing quantitative gait assessments, the Interactive Walkway may also be used to assess walking adaptability. The Interactive Walkway is equipped with a projector to augment the entire walkway with (gait-dependent) visual context, such as obstacles, sudden-stop-and-start cues and stepping targets, demanding step adjustments under time pressure demands in a safe manner. The aim of this thesis was to examine if 1) this approach can provide a valid assessment of walking ability and, if so, 2) if it has clinical potential in the assessment of walking ability and fall risk in patients with stroke and Parkinson’s Disease. Show less