In the early stages of development of drugs for neurological or psychiatric disorders, one of the most important questions is whether the drug crosses the blood‑brain barrier and shows pharmacological effects on the central nervous system. The desire to be able to provide an in-depth answer to this question has driven CHDR to develop the NeuroCart. However, execution of the NeuroCart tests was only possible at the CHDR clinical site. To overcome this barrier and allow for the tests to be performed at any clinical site around the world, CHDR has developed the NeuroKit.
The NeuroKit consists of a series of neuropsychological and neurophysiological tests that can be used to measure a wide range of CNS functions. Importantly, as a portable version of the NeuroCart, the NeuroKit can be used to correlate a compound’s CNS effects with drug concentration, helping to determine whether an effect is specifically due to the compound. The compound’s profile can also be compared to profiles of other compounds tested on the NeuroCart or the NeuroKit.
An overview of the NeuroKit tests
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Adaptive tracking measures visuomotor coordination and vigilance. Adaptive tracking is particularly sensitive to drugs that can induce ataxia. In this test, the subject uses a joystick to move a small dot so that it stays within a continuously moving circle in a Virtual Reality headset. During the test, the speed of the circle is adjusted in response to the subject’s ability to keep the dot in the circle, ensuring that the test is adapted to the individual subject.
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The body sway test measures the subject’s body movements in a single direction (usually forward/backward movement). Body sway is measured while the subject stands with his/her eyes closed. This is performed using an accelerometer attached at the lower back of the participant.
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The N-back test is a cognitive task used to assess working memory and attention. Participants are presented with a sequence of stimuli (e.g., letters or numbers) and must identify when the current stimulus matches one presented N steps earlier. The difficulty increases as the value of N rises, testing memory capacity and cognitive flexibility.
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The VAS Bond & Lader is a visual analogue scale used to assess subjective feelings of mood and alertness. It consists of a line, with endpoints representing extreme feelings such as "calm" to "anxious" or "alert" to "drowsy." Participants mark a point on the line that best represents their current state, and the position is later quantified to give a score.
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The VAS Bowdle is a visual analogue scale used to assess subjective feelings of sedation or sleepiness. It consists of a line with endpoints representing opposite feelings, such as "alert" and "sedated." Participants mark a point on the line that best reflects their current state of sedation.
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Saccadic eye movements are highly sensitive and specific measures of the subject’s alertness, sedation and tranquility. Saccadic peak velocity is one of the most sensitive measures of alertness currently available in drug research. Participants are using a Virtual Reality headset and are instructed to continuously look at a dot. As the dot ‘jumps’ from side to side on the screen, the response of each eye is monitored.
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Measuring smooth pursuit eye movements provides a measure of the participants’ coordination. In this test, the participant is using a Virtual Reality headset and is instructed to follow a dot as it moves smoothly from side to side.
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The finger tapping task is a simple motor test commonly used to assess fine motor control, coordination and neurological function. During the task, participants are asked to tap their finger (or fingers) against a tablet at a rapid pace for a set period, often with one hand or both hands simultaneously. The number of taps or the speed at which the participant can perform the task is measured. This task is used to evaluate cognitive and motor functions, and it can help detect neurological conditions, such as Parkinson's disease or other disorders that affect motor skills.
