Auditory CPT — Free Sound-Based Sustained Attention and Inhibition Test

The continuous performance test (CPT), first proposed by Rosvold and colleagues in 1956, measures the ability to sustain attention through a monotonous stream of stimuli, responding only to targets and withholding on the rest. Most CPTs use visual stimuli; this one uses sound alone. With no visual cue at all, the steadiness of the auditory attention pathway shows directly, revealing lapses in listening focus that visual tests tend to miss.

Two pure tones play one at a time for 0.2 seconds each. The high tone (880 Hz) is the target and plays 63 times; the low tone (440 Hz) is the non-target and plays 27 times — 90 tones in random order at 1.7-second intervals, taking about two minutes and 33 seconds. Press the button (or the space key) as soon as you hear the high tone, and withhold on the low tone. Because 70% of tones are targets, your hand gets used to pressing and must hold back on the occasional low tone, so response inhibition is measured as well.

The headline score is accuracy (%): the number of targets you responded to plus the number of non-targets you withheld on, divided by 90. At 95% or above, both sustained attention and response inhibition are described as steady; at 85% or above, performance is described as generally good; below that, omissions or false alarms were somewhat frequent. Omissions (missed targets) of 4 or fewer out of 63 and commissions (responses to non-targets) of 3 or fewer out of 27 are interpreted as low.

You also see the mean and standard deviation of reaction time on correct target responses, plus the coefficient of variation (CV, SD divided by mean); a CV under 0.22 is taken as consistent responding. The signal-detection index d′ shows how well you separated targets from non-targets — higher means better discrimination — and the response criterion c indicates a lean toward impulsive pressing when negative or cautious withholding when positive. Both are computed with a correction for extreme rates.

Because this is a sound-based test, a very low volume or listening through speakers can make the two tones hard to tell apart and increase omissions. Bluetooth earphones deliver sound late and can add tens of milliseconds to your mean reaction time, so use wired earphones or at least the same device setup each time and follow the trend.

Listening focus is disturbed most by ambient noise, so start in a quiet room with earphones and the volume set comfortably. Lack of sleep and fatigue raise both omissions and reaction-time variability, while caffeine speeds responses but can add false alarms. Longer reaction times with age are a natural change, and differences in hearing can make the two tones harder to distinguish, so keep that in mind when reading results.

Soundary saves your results and shows the change from your previous test. Repeating every one to two weeks with the same earphones and device at a similar time of day, and following the trend in accuracy, CV and d′, helps you tell condition-related fluctuation from steady change. This is a self-check, not a diagnostic tool.

If accuracy keeps falling below 85% or omissions remain frequent even when you retry well rested in a quiet setting, and in daily life you often tune out during conversations or lectures or miss being called by name, consider a hearing check along with an attention assessment from a professional.