TEST
Continuous Performance Test (CPT)
Vigilance, sustained attention, and inhibition under monotony
Continuous Performance Test inspired by Rosvold (1956) and designed following the parameters of Conners, Epstein, Angold, and Klaric (2003). A 14-minute go/no-go task with variable intervals that makes it possible to objectively measure inattention, impulsivity, slowness, and attentional fatigue.
360
TRIALS
14 min
DURATION
3
ISI (1, 2, 4 s)
90/10
GO/NO-GO (%)
WHAT THE TEST IS
Sustained vigilance during 14 minutes of monotony
Introduced by Rosvold et al. (1956) and popularized by Conners in ADHD, the CPT is the reference test for assessing sustained attention. Its go/no-go structure tests vigilance, perceptual discrimination (Signal Detection Theory), and inhibitory control.
Its apparent simplicity conceals high clinical sensitivity: it detects attentional difficulties in ADHD, multiple sclerosis, TBI, schizophrenia, and neurodegenerative diseases (Riccio et al., 2002; Huang-Pollock et al., 2012). The manipulation of intervals (1, 2, and 4 s) makes it possible to separate fast-processing problems from vigilant-maintenance problems during waiting periods.
HOW IT IS ADMINISTERED
Press for any letter except “X”
360 uppercase white letters are shown one by one on a black background for 250 ms. The user must press the space bar (or the touch area) for any letter except “X”. The target proportion is 90/10 (non-X letters / X letters).
The 360 trials are divided into 18 sub-blocks of 20 trials, with interstimulus intervals (ISI) of 1, 2, or 4 seconds randomized. There is no feedback during the test. The structure makes it possible to analyze the effect of presentation rate on speed and accuracy, and the evolution of performance by blocks (attentional fatigue).
WHAT THE TEST MEASURES
Indicators and their interpretation
The CPT generates a rich profile: global performance, speed-accuracy balance, perceptual sensitivity, response bias, and fatigue curves by block and by ISI.
Hits and omissions
Correct responses to target stimuli and missed targets. Measures sustained attention and vigilance.
High omissions: inattention, lapses, fatigue (typical of inattentive ADHD).
Hits close to 100%: preserved vigilance.
False alarms (commissions)
Responses given to an “X” (non-target stimulus). Direct marker of inhibitory control and impulsivity.
High FAs: impulsivity, inhibitory failure (frontal TBI, ADHD).
Low FAs: preserved inhibitory control.
Mean RT
Average reaction time in ms for hits. Measures processing speed and attentional efficiency.
High RT + errors: alertness or processing deficit.
Low RT + errors: impulsivity.
RT variability
Standard deviation of RTs. Especially sensitive marker of “minor lapses” in attention that do not always result in an omission.
High variability: fluctuating attention (ADHD, schizophrenia, TBI).
Low variability: consistent performance.
Sensitivity d’ and bias β
Signal Detection Theory indices. d’ measures the ability to discriminate target from non-target; β reflects the response criterion (conservative vs. liberal).
Low d’: reduced attentional sensitivity.
Liberal β: tendency to over-respond (impulsivity).
Fatigue (change by blocks)
Evolution of RT and errors across the 6 time blocks. Objectively measures the vigilance decrement characteristic of neurological conditions.
Progressive increase in RT/omissions: attentional fatigue (TBI, MS).
Stable performance: preserved mental endurance.
REFERENCES
Bibliography
- Rosvold, H. E., Mirsky, A. F., Sarason, I., Bransome, E. D., & Beck, L. H. (1956). A continuous performance test of brain damage. Journal of Consulting Psychology, 20(5), 343–350.
- Conners, C. K., Epstein, J. N., Angold, A., & Klaric, J. (2003). Continuous performance test performance in a normative epidemiological sample. Journal of Abnormal Child Psychology, 31(5), 555–562.
- Riccio, C. A., Reynolds, C. R., Lowe, P., & Moore, J. J. (2002). The continuous performance test: A window on the neural substrates for attention? Archives of Clinical Neuropsychology, 17(3), 235–272.
- Huang-Pollock, C. L., Karalunas, S. L., Tam, H., & Moore, A. N. (2012). Evaluating vigilance deficits in ADHD: A meta-analysis of CPT performance. Journal of Abnormal Psychology, 121(2), 360–371.
- Mackworth, N. H. (1948). The breakdown of vigilance during prolonged visual search. Quarterly Journal of Experimental Psychology, 1(1), 6–21.
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Measure vigilance, impulsivity, and attentional fatigue with millisecond precision over 14 minutes. Especially sensitive in ADHD, MS, TBI, and cognitive impairment.
