Mental fatigue, ‘brain fog’, and difficulties maintaining engagement are commonly reported issues in a range of neurological and psychiatric conditions. Traditional sustained attention tasks commonly measure this capacity as the ability to detect target stimuli based on sensory features in the auditory or visual domains. However, with this approach, discrete target stimuli may exogenously capture attention to aid detection, thereby masking deficits in the ability to endogenously sustain attention over time.

To address this, we developed the Continuous Temporal Expectancy Task (CTET) where individuals continuously monitor a stream of patterned stimuli alternating at a fixed temporal interval (690 ms) and detect an infrequently occurring target stimulus defined by a prolonged temporal duration (1020 ms or longer). As such, sensory properties of target and non-target stimuli are perceptually identical and differ only in temporal duration. Using the CTET, we assessed stroke survivors with unilateral right hemisphere damage (N = 14), a cohort in which sustained attention deficits have been extensively reported.

Stroke survivors had overall lower target detection accuracy compared with neurologically healthy age-matched older controls (N = 18). Critically, stroke survivors performance was characterised by significantly steeper within-block performance decrements, which occurred within short temporal windows (˜3 ½ min), and were restored by the break periods between blocks.

These findings suggest that continuous temporal monitoring taxes sustained attention processes to capture clinical deficits in this capacity over time, and outline a precise measure of the endogenous processes hypothesised to underpin sustained attention deficits following right hemisphere stroke.

精神疲劳、“脑雾”和难以保持参与是一系列神经和精神疾病中常见的问题。传统的持续注意力任务通常将这种能力测量为基于听觉或视觉域中的感官特征检测目标刺激的能力。然而，通过这种方法，离散的目标刺激可能会外源地吸引注意力以帮助检测，从而掩盖随着时间的推移内源性维持注意力的能力不足。

为了解决这个问题，我们开发了连续时间预期任务 (CTET)，其中个人连续监测以固定时间间隔 (690 ms) 交替的模式刺激流，并检测由延长的时间持续时间 (1020 ms 或更长）。因此，目标和非目标刺激的感觉特性在感知上是相同的，并且仅在时间持续时间上有所不同。使用 CTET，我们评估了患有单侧右半球损伤的中风幸存者 ( N = 14)，该队列已广泛报道持续注意力缺陷。

与神经健康的年龄匹配的老年对照相比，中风幸存者的目标检测准确度总体较低（N = 18）。至关重要的是，中风幸存者的表现的特点是明显更陡峭的块内性能下降，这发生在短时间窗口（~3 ½ 分钟）内，并通过块之间的休息时间恢复。

这些发现表明，持续的时间监测需要持续的注意力过程来捕捉这种能力随着时间的推移而出现的临床缺陷，并概述了对假设支持右半球中风后持续注意力缺陷的内源性过程的精确测量。