BARS Tests

Behavioral Assessment and Research System (BARS) tests

Continuous Performance test (CPT) – attention
Digit Span (DST) – attention, memory
Match-to-Sample (MS) – visual memory + delay
Oregon Dual Task Procedure (ODTP) – motivation, memory
Progressive Ratio (PR) – motivation
Reversal Learning (RL) – learning
Selective Attention Test (SAT) – attention
Serial Digit Learning (SDT) – learning
Simple Reaction Time (SRT) – response speed
Symbol Digit (SDT) – complex function
Tapping (TAP) – response speed, coordination

All BARS tests are detailed below, followed by FAQs about using BARS.

Continuous Performance Test (CPT)

FUNCTION MEASURED: Sustained visual attention

DESCRIPTION: A series of stimuli are presented one at a time for several minutes, typically 5-10. Subjects are instructed to press a key when a target is presented. There are two versions of the task, a single target version (A) and a cue-target version (A-X). In the single target version, subject responds when a single target appears. In the cue-target version, subject responds when a cue is followed by the target.

PRIMARY MEASURES

Reaction time
Number of hits
Errors of omission (failing to respond to a target)
Errors of commission (responding to stimuli other than the target)

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean

Use [token] dispenser during instructions (eg, for children)
Assessment Duration (time or 3 of trials)
Response keys (for left, right hand)
Duration (stimulus presentation, inter-stimulus interval)
Target type (target, cue/target)
Cue stimulus (eg, +)
Target stimulus (eg, o)
Stimulus size
Percent of stimuli that are targets
List of distracting stimuli

RELIABILITY: Correct latency measure 0.79

REFERENCE: Farahat et al., Measures of short-term test-retest reliability of computerized neurobehavioral tests. NeuroToxicology, 2003, 24: 513-521.

For further info, contact diane-rohlman@uiowa.edu.

Digit Span (DST)

FUNCTIONS MEASURED: Attention, memory

DESCRIPTION: A series of numbers is presented sequentially on the computer screen, and the subject is instructed to reproduce the sequence of numbers by pressing the numbered 9BUTTON buttons in the same order (forward) or in reverse order (backward). The number of digits increases until a failure criterion is met. Depicted (partial screen) is the final digit of a 4-digit presentation; subject responses appear in the rectangular boxes.

PRIMARY MEASURES

Longest span forward and backward
Every response during training and assessment is recorded

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Alternate spans (for repeat testing)
number of spans at each length presented
stimulus duration
success/fail criteria (1 out of 2 chances)

RELIABILITY (1 week test/retest; n=30) (Campbell et al., Assessment 1999, 6:21-32 )

0.60 (forward) [WAIS Digit Span is comparable: 0.56*]
0.61 (backward) [WAIS Digit Span is comparable: 0.70*]
*Beaumont and French; International J Man-Machine Studies, 1987, 26:661-682)

BASE REFERENCE: Anger et al.; Neurotoxicology and Teratology, 1996, 18: 371-379; 3 in press (see References)

For further info, contact diane-rohlman@uiowa.edu.

Match-to-Sample (MTS)

FUNCTION MEASURED: Visual memory

DESCRIPTION: A 10×10 matrix of blocks (pictured top) is followed by three choices (pictured bottom), among which one is the same as the sample stimulus.

PRIMARY MEASURES: Number correct, correct response latency

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Number of trials
Maximum number of timeouts, errors
Response keys
Show prompt screen during assessment
Patterns – number of boxes filled
Distractor boxes (number of boxes toggled in distractors)
Stimulus durations
Delay list (user selectable or random) – interval between presentation of sample stimulus and distractors

RELIABILITY: 0.69

BASE REFERENCE: Farahat et al., Measures of short-term test-retest reliability of computerized neurobehavioral tests. NeuroToxicology, 2003, 24: 513-521.

For further info, contact diane-rohlman@uiowa.edu.

Oregon Dual Task Procedure (ODTP)

FUNCTIONS MEASURED: Motivation, memory

DESCRIPTION: The ODTP is an implementation of a test of motivation, attention and memory. The ODTP consists of the presentation of a 5-digit number; followed by a vigilance (distractor) task for 5-, 15-, or 25-second intervals; followed by a forced choice between the original 5-digit number and a different (incorrect) alternative (the choice is depicted; partial screen).

PRIMARY MEASURES

Errors on the relatively easy forced choice between two response alternatives are indicative of motivation to perform neurobehavioral tests (by analogy with the non-computerized Portland Digit Recognition Test [PDRT] given to assess motivation in people suspected of having poor motivation [Binder and Willis; Psychological Assessment, 1991, 3: 175-181.]), although the literature suggests that poor motivation is convincingly demonstrated only by very poor performance (viz, 60% or less)
Latency on the forced choice items (subjects are not specifically instructed to work quickly)
Distractor task correct and incorrect, and latencies for both
Every response during training and assessment is recorded

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

target duration
number of 5-digit items+choices
distractor difficulty in each test segment (up to 5 digits)

RELIABILITY (1 week test/retest; n=30) (Campbell et al., Assessment 1999, 6:21-32 )

0.89 (correct)
0.90 (forced choice latency)
0.90 (distractor task latency)

BASE REFERENCE: Anger et al., Journal of the International Neuropsychology Society, 1999; 5:203-212

For further info, contact diane-rohlman@uiowa.edu.

Progressive Ratio (PR)

FUNCTION MEASURED: Motivation

DESCRIPTION: Responses on a button are “reinforced” by a smiling face and the increment of a number (similar to the score in a game). Each reinforcer is followed by an increase in the number of responses to achieve the reinforcer by a fixed amount (ie, the ratio of responses to reinforcer delivery becomes progressively larger). Depicted is the top of a PB screen in which 10 ratios have been completed.

PRIMARY MEASURES

number of ratios (and longest ratio) completed
every response during training and assessment is recorded

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Assessment duration (time or number of reinforcements)
Starting ratio size, step size, and break point

RELIABILITY (1 week test/retest): in data analysis

BASE REFERENCE: planned

For further info, contact diane-rohlman@uiowa.edu.

Reversal Learning (RevLrn)

FUNCTION MEASURED: Learning

DESCRIPTION: The subject learns the correct response (1 of 2 key options) when a list of stimuli are presented. Once the correct responses are learned (to a specific criterion) the correct response/duration is reversed. Depicted (partial screen) are instructions in training/practice.

PRIMARY MEASURES

Number of trials to learn
Number of trials to reverse

Every response during training and assessment is recorded for analysis

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Advancement criteria/success criterion (to reversal)
Response keys/buttons (1-9)
Maximum allowable time or errors
Stimulus shapes for the two stimulus classes
Random or fixed symbol-response pairings
Correction of errors (yes or no)
Basis for length of assessment: trials or reversal completions

RELIABILITY (1 week test/retest): in data analysis

BASE REFERENCE: planned

For further info, contact diane-rohlman@uiowa.edu.

Selective Attention Test (SAT) – Replaces Vigilant Attention Test

FUNCTION MEASURED: Attention

DESCRIPTION: A small dot is briefly presented inside or outside one of two squares, one on the left and one on the right half of the screen. The subject is instructed to press one button when a dot appears in the square on the left, a different button when the dot appears on the right (training depicted below in a partial screen image; in assessment dot is 1/2 size shown), and to not press a button when the dot appears outside of either square. The location and duration of the dot presentation and the basis on which the interval between dot presentations increases or decreases is user-selectable.

PRIMARY MEASURES

Number of trials
Percent correct latency
Every response during training and assessment is recorded

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Number of trials
Assessment duration (time or number of trials)
Response buttons/keys
Stimulus duration and percent left/right & in/out)
Interstimulus interval (time between dot presentations)
Titrate inter-stimulus interval (ISI) (yes/no)

RELIABILITY (1 week test/retest; n=29): 0.71 (correct) (Campbell et al., Assessment 1999, 6:21-32 )

BASE REFERENCES:
Campbell et al., Assessment 1999, 6:21-32
variant: Anger et al.; Neurotoxicology and Teratology, 1996, 18: 371-379

For further info, contact diane-rohlman@uiowa.edu.

Serial Digit Learning (SDL)

FUNCTION MEASURED: Learning

DESCRIPTION: Up to nine digits are presented sequentially, and the subject is instructed to repeat the 9-digit sequence on the 9BUTTON, until a success or failure criterion is met. Depicted is the second digit of a 9-digit sequence (partial screen).

PRIMARY MEASURES

Number of trials
Score ranging from 0-24 (worst to best)
Every response during training and assessment is recorded for analysis

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Number of digits in the sequence (9 = maximum)
Alternate testing sequence (for repeat testing)
Stimulus duration and interstimulus interval (ISI)
Criterion for ending test (2 correct in a row)

RELIABILITY (1 week test/retest; n=30): 0.63 (correct) (Campbell et al.,Assessment 1999, 6:21-32)

BASE REFERENCE: Anger et al., Journal of the International Neuropsychology Society, 1999; 5:203-212

For further info, contact diane-rohlman@uiowa.edu.

Simple Reaction Time (SRT)

FUNCTION MEASURED: Response speed

DESCRIPTION: The subject is instructed to respond by pressing a 9BUTTON as quickly as possible after they see a stimulus presented on the screen or when a 9BUTTON response button becomes backlighted. A partial screen image of the instructions is depicted.

PRIMARY MEASURES

Response latency or reaction time
Every response during training and assessment is recorded for analysis

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)

Stimulus shape
Response button/key
Basis for time between stimuli (eg, random, WHO NCTB intervals) – ISI times
Mean duration of stimulus and mean time between stimuli (NES/SPES)
Assessment duration (time or number of trials)

RELIABILITY (1 week test/retest; n=30): 0.81 (Campbell et al., Assessment 1999, 6:21-32 )

BASE REFERENCES

Anger et al.; Neurotoxicology and Teratology, 1996, 18: 371-379
Rohlman et al.; Neurotoxicology and Teratology, 1996, 18: 407-412

For further info, contact diane-rohlman@uiowa.edu.

Symbol-Digit (SDT)

FUNCTIONS MEASURED: Complex functions

DESCRIPTION: This is described as a coding test in which digits are paired with symbols in a 2 squares by 9 squares matrix. A similar matrix at the bottom of the screen contains the symbols but not the digits. The subject is instructed to type the correct numbers (ie, that correspond with the respective symbols) in the empty matrix spaces.

PRIMARY MEASURES

Latency to complete the matrices;
Errors [primarily used to confirm effective performance]
Every response during training and assessment is recorded for analysis

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)
Assessment duration (number of matrices)
Symbol-Digit pairings (random or fixed)
Alternate symbol/digit pairs (for repeat testing)

RELIABILITY (1 week test/retest): 0.92 (Campbell et al., Assessment 1999, 6:21-32 )

BASE REFERENCES

Anger et al.; Behavior Research Methods, Instrumentation, Computers, 1994, 26: 209-212
Anger et al.; Neurotoxicology and Teratology, 1996, 18: 371-379
Rohlman et al.; Neurotoxicology and Teratology, 1996, 18: 407-412

For further info, contact diane-rohlman@uiowa.edu.

Tapping (Tap)

FUNCTIONS MEASURED: Response speed, coordination

DESCRIPTION: The subject is instructed to press (tap) button(s) as rapidly as possible using the index finger of one or both hands on one or two buttons. Responses incrementally increase the height of a dark bar (depicted) to suggest progress to the subject.

PRIMARY MEASURES

Number of taps completed or time to complete a fixed number of taps
Every response during training and assessment is recorded for analysis

PARAMETERS (test settings that can be selected by the user, or you can use our default setting)

Instructions

stepped vs. single screen – for repeat testing

written – spoken
Languages: English – Spanish – Portuguese – Korean – Arabic

Use [token] dispenser during instructions (eg, for children)
Assessment
Trial sequence of right-, left-/preferred-, nonpreferred-, alternating [one or both]-hand trials
Break duration between trials
Response buttons/keys
Assessment duration basis: time or number of taps

RELIABILITY (1 week test/retest; n=30) (Campbell et al., Assessment 1999, 6:21-32)

0.44 (preferred)
0.65 (non-preferred)
0.84 (alternating hands)

BASE REFERENCE: Campbell et al., Assessment 1999, 6:21-32

For further info, contact diane-rohlman@uiowa.edu.

Frequently Asked Questions (FAQ)

• Which BARS tests should I use?
> Select tests based on the functions expected to be affected by the neurotoxic chemical the target audience is exposed to.

• How long do the BARS tests take?
> The number of trials, duration of testing, and/or difficulty level of BARS tests can be set to lengthen or shorten the test duration.Â However, all BARS tests are self-paced so the participants control the duration of testing to a significant degree.

• How long should a test session last?
> 50 minutes is a good target. However, with breaks, we have tested people for as long as 4 hours when the protocol required it.

• Is BARS used for individual clinical testing?
> No. BARS is used for epidemiological research. There are no norms; published epidemiological research with BARS serves as a guide, however.