Concurrent Validity Study Research Articles

Memory Performance and Quantitative Neuroimaging Software in Mild Cognitive Impairment: A Concurrent Validity Study.

This study examined the relationship between patient performance on multiple memory measures and regional brain volumes using an FDA-cleared quantitative volumetric analysis program - Neuroreader™. Ninety-two patients diagnosed with mild cognitive impairment (MCI) by a clinical neuropsychologist completed cognitive evaluations and underwent MR Neuroreader™ within 1 year of testing. Select brain regions were correlated with three widely used memory tests. Regression analyses were conducted to determine if using more than one memory measures would better predict hippocampal z-scores and to explore the added value of recognition memory to prediction models. Memory performances were most strongly correlated with hippocampal volumes than other brain regions. After controlling for encoding/Immediate Recall standard scores, statistically significant correlations emerged between Delayed Recall and hippocampal volumes (rs ranging from .348 to .490). Regression analysis revealed that evaluating memory performance across multiple memory measures is a better predictor of hippocampal volume than individual memory performances. Recognition memory did not add further predictive utility to regression analyses. This study provides support for use of MR Neuroreader™ hippocampal volumes as a clinically informative biomarker associated with memory performance, which is a critical diagnostic feature of MCI phenotype.

Can an Observational Gait Scale Produce a Result Consistent with Symmetry Indexes Obtained from 3-Dimensional Gait Analysis?: A Concurrent Validity Study.

To investigate whether a simple observational tool may be a substitute to the time-consuming and costly 3-dimensional (3D) analysis, the study applied the Wisconsin Gait Scale (WGS), enabling assessment which is highly consistent with 3D gait parameters in patients after a stroke. The aim of this study was to determine whether, and to what extent, observational information obtained from WGS-based assessment can be applied to predict results of 3D gait analysis for selected symmetry indicators related to spatiotemporal and kinematic gait parameters. Fifty patients at a chronic stage of recovery post-stroke were enrolled in the study. The spatiotemporal and kinematic gait parameters were measured using a movement analysis system. The symmetry index (SI), was calculated for selected gait parameters. The patients’ gait was evaluated by means of the WGS. It was shown that stance % SI, as well as hip and knee flexion-extension range of motion SI can most effectively be substituted by WGS-based estimations (coefficient of determination exceeding 80%). It was shown that information acquired based on the WGS can be used to obtain results comparable to those achieved in 3D assessment for selected SIs of spatiotemporal and kinematic gait parameters. The study confirms that observation of gait using the WGS, which is an ordinal scale, is consistent with the selected aims of 3D assessment. Therefore, the scale can be used as a complementary tool in gait assessment.

Correlation Between Clinical Assessment and Lymphofluoroscopy in Patients with Breast Cancer-Related Lymphedema: A Study of Concurrent Validity.

Background: A disturbance of the superficial lymphatic system (dermal backflow) in patients with breast cancer-related lymphedema (BCRL) can be visualized by near-infrared fluorescence imaging or lymphofluoroscopy. In clinical practice, exact measurement of the dermal backflow is difficult. The purpose of the study is to investigate the concurrent validity between the clinical assessments and the lymphofluoroscopy in patients with BCRL. Methods and Results: Forty-five patients with BCRL stage I to IIb received lymphofluoroscopy and clinical assessments of their edematous limb (pitting status, skinfold thickness, skin elasticity, water content, lymphedema volume, and extracellular fluid). The correlation between the clinical assessments and the result of the lymphofluoroscopy was determined. The best overall agreement with dermal backflow was found for the clinical assessment pitting status, skinfold thickness, and water content. Overall sensitivity was excellent for lymphedema volume (92.5%), high for skinfold thickness (86.6%) and water content (75.0%), and moderate for pitting status (67.7%). Overall specificity was excellent for skin elasticity (94.7%), high for pitting status (83.4%), and moderate for skinfold thickness (61.6%) and water content (74.8%). In the evaluation of the whole arm, measurements of the excess volume were significantly greater for patients in an advanced stage of dermal backflow in comparison with patients in an earlier stage of dermal backflow (p = 0.002). Conclusions: The clinical assessments of skinfold thickness, water content, and lymphedema volume are the most appropriate tools to detect dermal backflow according to the lymphofluoroscopic images. To confirm the absence of dermal backflow, pitting status can be recommended.

Reliability and validity of a sedentary behavior questionnaire for South American pediatric population: SAYCARE study

BackgroundMulticenter studies from Europe and the United States have developed specifically standardized questionnaires for assessing and comparing sedentary behavior, but they cannot be directly applied for South American countries. The aim of this study was to assess the reliability and validity of the South American Youth Cardiovascular and Environmental (SAYCARE) sedentary behavior questionnaire.MethodsChildren and adolescents from seven South American cities were involved in the test-retest reliability (children: n = 55; adolescents: n = 106) and concurrent validity (children: n = 93; adolescents: n = 94) studies. The SAYCARE sedentary behavior questionnaire was administered twice with two-week interval and the behaviors were parent-reported for children and self-reported for adolescents. Questions included time spent watching television, using a computer, playing console games, passive playing (only in children) and studying (only in adolescents) over the past week. Accelerometer was used for at least 3 days, including at least one weekend day. We compared values of sedentary time, using accelerometers, by quartiles of reported sedentary behavior time and their sum.ResultsThe reliability of sedentary behavior time was moderate for children (rho ≥0.45 and k ≥ 0.40) and adolescents (rho ≥0.30). Comparisons between the questionnaire and accelerometer showed a low overall agreement, with the questionnaire systematically underreporting sedentary time in children (at least, − 332.6 ± 138.5 min/day) and adolescents (at least, − 399.7 ± 105.0 min/day).ConclusionThe SAYCARE sedentary behavior questionnaire has acceptable reliability in children and adolescents. However, the findings of current study indicate that SAYCARE questionnaire is not surrogate of total sedentary time.

The SED-GIH: A Single-Item Question for Assessment of Stationary Behavior-A Study of Concurrent and Convergent Validity.

The unfavorable health consequences of prolonged time spent sedentary (stationary) make accurate assessment in the general population important. However, for many existing questionnaires, validity for identifying stationary time has not been shown or has shown low validity. This study aimed to assess the concurrent and convergent validity of the GIH stationary single-item question (SED-GIH). Data were obtained in 2013 and 2014 from two Swedish cohorts. A total of 711 men and women provided valid accelerometer data (Actigraph GT3X+) and were included for concurrent validity analyses. A total of 560 individuals answered three additional commonly used sedentary questions, and were included for convergent validity analysis. The SED-GIH displayed a significant correlation with total stationary time (rs = 0.48) and time in prolonged stationary time (rs = 0.44). The ROC analysis showed an AUC of 0.72 for identifying individuals with stationary time over 600 min/day. The SED-GIH correlated significantly with other previously used questions (r = 0.72–0.89). The SED-GIH single-item question showed a relatively high agreement with device-assessed stationary behavior and was able to identify individuals with high levels of stationary time. Thus, the SED-GIH may be used to assess total and prolonged stationary time. This has important implications, as simple assessment tools of this behavior are needed in public health practice and research.

Estimating dyskinesia severity in Parkinson\u2019s disease by using a waist-worn sensor: concurrent validity study

Our research team previously developed an accelerometry-based device, which can be worn on the waist during daily life activities and detects the occurrence of dyskinesia in patients with Parkinson’s disease. The goal of this study was to analyze the magnitude of correlation between the numeric output of the device algorithm and the results of the Unified Dyskinesia Rating Scale (UDysRS), administered by a physician. In this study, 13 Parkinson’s patients, who were symptomatic with dyskinesias, were monitored with the device at home, for an average period of 30 minutes, while performing normal daily life activities. Each patient’s activity was simultaneously video-recorded. A physician was in charge of reviewing the recorded videos and determining the severity of dyskinesia through the UDysRS for every patient. The sensor device yielded only one value for dyskinesia severity, which was calculated by averaging the recorded device readings. Correlation between the results of physician’s assessment and the sensor output was analyzed with the Spearman’s correlation coefficient. The correlation coefficient between the sensor output and UDysRS result was 0.70 (CI 95%: 0.33–0.88; p = 0.01). Since the sensor was located on the waist, the correlation between the sensor output and the results of the trunk and legs scale sub-items was calculated: 0.91 (CI 95% 0.76–0.97: p < 0.001). The conclusion is that the magnitude of dyskinesia, as measured by the tested device, presented good correlation with that observed by a physician.

Concurrent Validity of a Commercial Wireless Trunk Triaxial Accelerometer System for Gait Analysis.

Wearable sensor devices have notable advantages, such as cost-effectiveness, easy to use, and real-time feedback. Wirelessness ensures full-body motion, which is required during movement in a challenging environment such as during sports. Research on the reliability and validity of commercially available systems, however, is indispensable. To confirm the test-retest reliability and concurrent validity of a commercially available body-worn sensor-BTS G-WALK® sensor system-for spatiotemporal gait parameters with the GAITRite® walkway system as golden standard. Reliability and concurrent validity study. Laboratory setting. Thirty healthy subjects. Spatiotemporal parameters: speed, cadence, stride length, stride duration, stance duration, swing duration, double support, and single support. In terms of test-retest reliability of the BTS G-WALK® sensor system, intraclass correlation coefficient values for both the spatial and temporal parameters were excellent between consecutive measurements on the same day with intraclass correlation coefficient values ranging from .85 to .99. In terms of validity, intraclass correlation coefficient values between measurement systems showed excellent levels of agreement for speed, cadence, stride length, and stride duration (range = .88-.97), and showed poor to moderate levels of agreement (range = .12-.47) for single/double support and swing/stance duration. Bland-Altman plots showed overall percentage bias values equal to or smaller than 3% with limits of agreement ≤15% (speed, cadence, stride length, stride duration, swing duration, and stance duration). Only for single and double support, the limits of agreement were higher with, respectively, -15.4% to 19.5% and -48.0% to 51.4%. The BTS G-WALK® sensor system is reliable for all measured spatiotemporal parameters. In terms of validity, excellent concurrent validity was shown for speed, cadence, stride length, and stride duration. Cautious interpretation is necessary for temporal parameters based on final foot contact (stance, swing, and single/double support time).

Reliability and validity studies of the Turkish version of Humor Styles Questionnaire for Children

This article presents the investigation of the psychometric properties of the Turkish version of the Humor Styles Questionnaire for Children (CHSQ Turkish). Four studies were assessed using a sample of Turkish secondary school students in two different schools located in Istanbul and a total of 717 students participated in these four studies. Factor analyses and internal consistency (study 1), test-retest reliability (study 2), concurrent validity (study 3), convergent and discriminant validity (study 4) were investigated in this research. In study 1, the results of the confirmatory and exploratory factor analysis indicated that the four-factor structure (aggressive, affiliative, self-enhancing, self-defeating) of a modified 17-item version was confirmed. In addition, corrected item-total correlations (.50–.70) and internal consistency values of the four factors were acceptable (.82, .83, .80, .73, respectively). Test-retest reliabilities during a 4-week period (.69, .82, .74, .72, respectively) were adequate in study 2. In study 3, concurrent validity of the scale was supported with reference to depression and anxiety. In study 4, convergent and discriminant validity of the CHSQ Turkish were confirmed by assessing AVE, square root of AVE and correlations between four factors. Additionally, the correlations of the four factors of the scale with sensation seeking and loneliness were additional evidence for convergent validity. The CHSQ Turkish was assessed to be a valid and reliable measure.

Adaptation of the prosocial behavioral intentions scale for use with Turkish participants: Assessments of validity and reliability

This study adapted and investigated the psychometric properties of the Prosocial Behavioral Intentions Scale (PBIS) in a Turkish sample in four sub-studies. Findings of a confirmatory factor analysis (Study 1), and tests of internal consistency and test-retest reliability (Study 2), concurrent validity (Study 3), convergent, and discriminant validity (Study 4), have been presented in this article. The confirmatory factor analysis conducted in Study 1 indicated that the unidimensional-factor structure had the best fit to the data. Study 2 found that the internal consistency value was acceptable and test-retest reliability over a 4-week period was adequate. Study 3 supported the concurrent validity of the Turkish PBIS with reference to altruism and empathy. In Study 4, convergent validity was established based on the correlation between the Adult Prosocialness Scale (APS) and Turkish PBIS. Factor loadings and t-values of the items, composite reliability (CR), and the Average Variance Extracted (AVE) value of the Turkish PBIS were optimal. Discriminant validity was confirmed based on the correlation between the Turkish PBIS and Social Appearance Anxiety Scale (SAAS), with adequate cross-loadings of the PBIS and the Fornell and Larcker criterion. Thus, the Turkish PBIS was found to be a brief, valid, and reliable measure of prosocial behaviors.

Can we use GPS for assessing sprinting performance in rugby sevens? A concurrent validity and between-device reliability study.

The purpose of this study was to (1) provide data on maximal sprinting speed (MSS) and maximal acceleration (Amax) in elite rugby sevens players measured with GPS devices, (2) test the concurrent validity of the signal derived from a radar device and a commercially available 16 Hz GPS device, and (2) assess the between-device reliability of MSS and Amax of the same GPS. Fifteen elite rugby sevens players (90 ± 12 kg; 181 ± 8 cm; 26 ± 5 y) participated in the maximal sprinting test. A subset of five players participated in the concurrent validity and between-devices reliability study. A concurrent validity protocol compared the GPS units and a radar device (Stalker ATS II). The between-device reliability of the GPS signal during maximal sprint running was also assessed using 6 V2 GPS units (Sensorevery-where, Digital Simulation, Paris, France) attached to a custom-made steel sled and pushed by the five athletes who performed a combined total of 15 linear 40m sprints. CV ranged from 0.5, ±0.1 % for MSS and smoothed MSS to 6.4, ±1.1 % for Amax. TEM was trivial for MSS and smoothed MSS (0.09, ±0.01) and small for Amax and smoothed Amax (0.54, ±0.09 and 0.39, ±0.06 respectively). Mean bias ranged from -1.6, ±1.0 % to -3.0, ±1.1 % for smoothed MSS and MSS respectively. TEE were small (2.0, ±0.55 to 1.6, ±0.4 %, for MSS and smoothed MSS respectively. The main results indicate that the GPS units were highly reliable for assessing MSS and provided acceptable signal to noise ratio for measuring Amax, especially when a smoothing 0.5-s moving average is used. This 16 Hz GPS device provides sport scientists and coaches with an accurate and reliable means to monitor running performance in elite rugby sevens.

Early neonatal near miss identified through health information systems

The aim of this study was to validate a definition to identify cases of early neonatal near miss using data from health information systems (SIS in Portuguese). This was a concurrent validation study focusing on three definitions for identification of cases of early neonatal near miss among live births in a university hospital in 2012. Three different definitions were applied to this live birth cohort using the criteria birth weight, gestational age, 5-minute Apgar score, admission to the neonatal intensive care unit, mechanical ventilation, and congenital malformations, in different combinations, considering the proposals in two Brazilian articles (Silva et al.; Pillegi-Castro et al.) and a third (SIS definition) with available data from health information systems. Cases were defined as infants that had survived the risk conditions as of the 7th day of life. For concurrent validation, the study adopted early neonatal deaths as the reference. Of the 2,097 live births studied, 33 died in the early neonatal period, and the number of cases of early neonatal near miss varied according to the definition used: 153 (Silva definition), 194 (Pileggi-Castro definition), and 304 (SIS definition). Sensitivity and specificity were 97% and 92.6%, respectively, according to the Silva definition, 90.9% and 90.6% according to the Pileggi-Castro definition, and 93.9% and 85.3% according to the SIS definition. The results show that the SIS definition has sensitivity and specificity close to the other definitions and suggest that it is possible to monitor early neonatal near miss using only data that are available in official health information systems.

Validation of a Wearable Sensor for Measuring Running Biomechanics

Background: Running biomechanics have traditionally been analyzed in laboratory settings, but this may not reflect natural running gait. Wearable sensors may offer an alternative. Methods: A concurrent validation study to determine agreement between the RunScribe^TM wearable sensor (triaxial accelerometer and gyroscope) and the 3D motion capture system was conducted. Twelve injury-free participants (6 males, 6 females; age = 23.1 ± 5.5 years, weekly mileage = 16.1 ± 9.3) ran 1.5 miles on a treadmill. Ten consecutive strides from each limb were collected, and the mean values were analyzed. Pronation excursion, maximum pronation velocity, contact time, and cycle time were compared between measurement platforms using intraclass correlation coefficients (ICC) and Bland-Altman analyses. Results: Excellent ICC estimates were found for maximum pronation velocity, contact time, and cycle time. Pronation excursion demonstrated fair ICC estimates. The mean differences between platforms were small with limits of agreement clustered around zero, except for contact time measures which were consistently higher with the RunScribe compared to the camera-based system. Conclusion: Our study revealed that the RunScribe wearable device showed good to excellent concurrent validity for maximum pronation velocity, contact time, and cycle time; however, direct comparisons or results between the two platforms should not be used.

Idea Adoption in Workplace Innovation: Scale Development and Initial Validity Evidence

Despite the importance of workplace innovation, the adoption of creative ideas at workplace level has received little attention owing to a lack of measures for idea adoption. The purpose of this study was to develop and validate a scale that measures the process of idea adoption. More specific, the scale assesses the behavior of supervisory leaders in terms of idea openness, selection and application. Three studies were conducted to develop the idea adoption scale and investigate its psychometric properties (Study 1, n = 326); establish concurrent, convergent and divergent validity (Study 2, n = 334); and assess test-retest reliability over a three month period (Study 3, n = 189). The findings showed that the full idea adoption scale and its subscales have good psychometric properties: the three factor structure was supported and scales showed internal consistency and retest reliability. Furthermore, the scales’ associations with other variables provided initial evidence for concurrent, convergent and divergent validity. Several recommendations are made for the application of the scale in research and practice.

Applying Item Response Trees to Personality Data in the Selection Context

Self-report personality scales are used frequently in personnel selection. Traditionally, researchers have assumed that individuals respond to items within these scales using a single-decision process. More recently, a flexible set of item response (IR) tree models have been developed that allow researchers to investigate multiple-decision processes. In the present research, we found that IR tree models fit the data better than a single-decision IR model when fitted to seven self-report personality scales used in a concurrent criterion-related validity study. In addition, we found evidence that the latent variable underlying the direction of a response (agree or disagree) decision process predicted job performance better than latent variables reflecting the other decision processes for the best fitting IR tree model.

Assessment of cam morphology of the hip with ultra sound imaging by physical therapists is reliable and valid

BackgroundFemoroacetabular impingement syndrome is considered present when a combination of clinical symptoms, signs and morphological features of the hip co-exist. Imaging is increasingly popular in primary health care settings with physical therapists performing ultrasound (US). ObjectiveThe aim of this study was to assess the diagnostic accuracy and inter-rater reliability of ultrasound in determining presence of cam morphology. DesignA concurrent validity and inter-rater reliability study. MethodsThe presence of cam morphology of the hip was determined by α angle measures using Kinovea software. A cam was defined present when the α angle >60°. The index test was US and radiographs served as a gold standard. ResultsCorrelation between the radiographic α angle and ultrasound measures was r = 0.82 (p < 0.01). Inter-rater reliability was high with an ICC of 0.74 (95% CI 0.61–0.84).The predictive value for presence of cam morphology had a sensitivity of 79% and a specificity of 94%. The positive predictive value was 79% whereas the negative predictive value was 94%. Total accuracy was 90%. ConclusionsUltrasound conducted by trained physical therapists is a valid, reliable, specific and sensitive diagnostic tool to assess the presence of cam morphology.

Capturing patient-reported area of knee pain: a concurrent validity study using digital technology in patients with patellofemoral pain.

BackgroundPatellofemoral pain (PFP) is often reported as a diffuse pain at the front of the knee during knee-loading activities. A patient’s description of pain location and distribution is commonly drawn on paper by clinicians, which is difficult to quantify, report and compare within and between patients. One way of overcoming these potential limitations is to have the patient draw their pain regions using digital platforms, such as personal computer tablets.ObjectiveTo assess the validity of using computer tablets to acquire a patient’s knee pain drawings as compared to paper-based records in patients with PFP.MethodsPatients (N = 35) completed knee pain drawings on identical images (size and colour) of the knee as displayed on paper and a computer tablet. Pain area expressed as pixel density, was calculated as a percentage of the total drawable area for paper and digital records. Bland–Altman plots, intraclass correlation coefficient (ICC), Pearson’s correlation coefficients and one-sample tests were used in data analysis.ResultsNo significant difference in pain area was found between the paper and digital records of mapping pain area (p = 0.98), with the mean difference = 0.002% (95% CI [−0.159–0.157%]). A very high agreement in pain area between paper and digital pain drawings (ICC = 0.966 (95% CI [0.93–0.98], F = 28.834, df = 31, p < 0.001). A strong linear correlation (R2 = 0.870) was found for pain area and the limits of agreement show less than ±1% difference between paper and digital drawings.ConclusionPain drawings as acquired using paper and computer tablet are equivalent in terms of total area of reported knee pain. The advantages of digital recording platforms, such as quantification and reporting of pain area, could be realized in both research and clinical settings.

Dirty Dozen Scale: a study of adaptation to Turkish university students

Objective: In recent years, Machiavellianism, psychopathy and narcissism have been considered together as the dark sides of the personality. In this study, the purpose is to adapt the Dirty Dozen Scale to Turkish culture. Meth-ods: Four steps have been conducted in this study. These studies are linguistic equivalence study, structure and concurrent validity study, predictive validity study, and reliability study, respectively. Nine hundred and thirty-two university students (61% female), who were included in the four steps, participated in the study. Results: Applying a confirmatory factor analysis [χ2(51,430)=145.16, p

A novel approach for intra-operative shape acquisition of the tibio-femoral joints using 3D laser scanning in computer assisted orthopaedic surgery.

Image registration (IR) is an important process of developing a spatial relationship between pre-operative data and the physical patient in the operation theatre. Current IR techniques for Computer Assisted Orthopaedic Surgery (CAOS) are time consuming and costly. There is a need to automate and accelerate this process. Bespoke quick, cost effective, contactless and automated 3D laser scanning techniques based on the DAVID Laserscanner method were designed. 10 cadaveric knee joints were intra-operatively laser scanned and were registered with the pre-operative MRI scans. The results are supported with a concurrent validity study. The average absolute errors between scan models were systematically less than 1 mm. Errors on femoral surfaces were higher than tibial surfaces (P<0.05). Additionally, scans acquired through the large exposure produced higher errors than the smaller exposure (P<0.05). This study has provided proof of concept for a novel automated shape acquisition and registration technique for CAOS.

Development and Validation of Objective Performance Metrics for Robot-Assisted Radical Prostatectomy: A Pilot Study.

We explore and validate objective surgeon performance metrics using a novel recorder ("dVLogger") to directly capture surgeon manipulations on the da Vinci® Surgical System. We present the initial construct and concurrent validation study of objective metrics during preselected steps of robot-assisted radical prostatectomy. Kinematic and events data were recorded for expert (100 or more cases) and novice (less than 100 cases) surgeons performing bladder mobilization, seminal vesicle dissection, anterior vesicourethral anastomosis and right pelvic lymphadenectomy. Expert/novice metrics were compared using mixed effect statistical modeling (construct validation). Expert reviewers blindly rated seminal vesicle dissection and anterior vesicourethral anastomosis using GEARS (Global Evaluative Assessment of Robotic Skills). Intraclass correlation measured inter-rater variability. Objective metrics were correlated to corresponding GEARS metrics using Spearman's test (concurrent validation). The performance of 10 experts (mean 810 cases, range 100 to 2,000) and 10 novices (mean 35 cases, range 5 to 80) was evaluated in 100 robot-assisted radical prostatectomy cases. For construct validation the experts completed operative steps faster (p <0.001) with less instrument travel distance (p <0.01), less aggregate instrument idle time (p <0.001), shorter camera path length (p<0.001) and more frequent camera movements (p <0.03). Experts had a greater ratio of dominant-to-nondominant instrument path distance for all steps (p <0.04) except anterior vesicourethral anastomosis. For concurrent validation the median experience of 3 expert reviewers was 300 cases (range 200 to 500). Intraclass correlation among reviewers was 0.6-0.7. For anterior vesicourethral anastomosis and seminal vesicle dissection, kinematic metrics had low associations with GEARS metrics. Objective metrics revealed experts to be more efficient and directed during preselected steps of robot-assisted radical prostatectomy. Objective metrics had limited associations to GEARS. These findings lay the foundation for developing standardized metrics for surgeon training and assessment.

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: IV. The Pause Marker Index.

Three previous articles provided rationale, methods, and several forms of validity support for a diagnostic marker of childhood apraxia of speech (CAS), termed the pause marker (PM). Goals of the present article were to assess the validity and stability of the PM Index (PMI) to scale CAS severity. PM scores and speech, prosody, and voice precision-stability data were obtained for participants with CAS in idiopathic, neurogenetic, and complex neurodevelopmental disorders; adult-onset apraxia of speech consequent to stroke and primary progressive apraxia; and idiopathic speech delay. Three studies were completed including criterion and concurrent validity studies of the PMI and a temporal stability study of the PMI using retrospective case studies. PM scores were significantly correlated with other signs of CAS precision and stability. The best fit of the distribution of PM scores to index CAS severity was obtained by dividing scores into 4 ordinal severity classifications: mild, mild-moderate, moderate-severe, and severe. Severity findings for the 4 classifications and retrospective longitudinal findings from 8 participants with CAS supported the validity and stability of the PMI. Findings support research and clinical use of the PMI to scale the severity of CAS.