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Drug trials

Drug trials: measuring the link between caffeine and alertness with Optalert

Caffeine has always been known as a stimulant for wakefulness. But if being alert is the main reason for drinking a cup of coffee, what would it do for those who are well-rested, not drowsy and in a non-sleepy environment?

In 2008, world-renowned sleep doctor and Optalert Founding Director Dr Murray Johns together with Natalie Michael, Caroline Owen and John Patterson studied the effects of caffeine on alertness as measured by infrared reflectance oculography. Their findings were published in Psychopharmacology (Volume 200, Issue 2, pp 255–260).

Researchers used 12 “low” and “non-users” of caffeine as participants of the study.

The study was based on the following conditions:


Participants and investigators do not know if they are receiving the caffeine tablet or the placebo.


Participants were given both the caffeine tablets and the placebos but on different days


Half the participants take caffeine (Drug A) on their first experimental day and the other half take the placebo (Drug B).

The participants completed a short vigilance at baseline and then at the following intervals after ingestion:

During testing at each of the four intervals above (and at baseline) participants’ alertness levels were measured using Optalert’s infrared ocular technology. By simply wearing a pair of Optalert glasses during each test, participants’ eyelids were measured at a rate of 500 times per second.

Measurements include:

The data collected is dense, but from this data we are able to also reveal a simple score on a scale from 0-10.

JDS score

This scale, the Johns Drowsiness Scale (JDS), was established by Dr Murray Johns and can literally put a number on how drowsy or alert a person is. The simple 10-point scale lets users quickly identify an objective measure of drowsiness and alertness, where a JDS score of 0 = very alert while a score of 10 = very drowsy.

Karolinska Sleepiness Scale

Participants also used the Karolinska Sleepiness Scale (KSS) to self-report their alertness level.

Results of the study show that caffeine significantly lessened the drowsiness state and reaction times according to the collected JDS scores that lasted for 3-4 hours.

Optalert’s JDS accurately measures real-time drowsiness

Results of the study showed that there was no significant difference between the caffeine and placebo groups in terms of reaction time, subjective assessment of alertness (KSS) and objective assessment of alertness (JDS) prior to caffeine or placebo ingestion.

However, after intake, the caffeine group performed faster during their tests and also reported feeling more alert. The JDS also effectively detected the changes resulting from caffeine intake, where a tangible difference in performance and alertness emerged.

Traditionally, caffeine has demonstrated little perceptible effect on ocular movement, but for the first time ever, the JDS has successfully identified even the smallest fluctuations in a participant’s eye movement to show a correlation between caffeine ingestion and alertness.

Pharmaceutical and clinical trials

The pharmaceutical industry continues to adopt new and advanced ways to gather data, analyse results, and develop market-ready products.

The increase in production of new drugs in the market moves into deliberate ways on how to conduct testing and clinical trials. All drugs must go through stringent stages of testing before they are approved and finally ready for sale.

Public health and safety is at the core of these tests, which may take up to 15 years to complete.

Introducing Optalert’s technology into pharmaceutical applications enhances existing testing with faster and more accurate and sensitive real-time data.

Sleeping tablets

Most people take sleeping pills or calming tablets that are popularly known to promote sleep. Doctors may recommend drugs to assist with common (but short-term) sleeping problems.

Drowsiness has also been a side effect of some medicines in the market. The eagle RESEARCH accurately measures the performance of these sleep-related drugs in terms of efficacy and the time measured from its intake to activity.

How Optalert’s technology is used during pharmaceutical drug trials

This study demonstrates how drowsiness can be objectively measured in real time with the JDS. The direct link between drowsiness and the effects on an individual’s level of attentiveness and concentration become more than just observations; these findings are critical in maintaining not only public safety, but overall health and wellbeing, too.

Results of the JDS scores can also be used to verify the pharmacokinetic properties of a new drug just like measuring the level of intake and viability of caffeine as done in this study.

Pharmaceutical companies benefit from Optalert’s eagle RESEARCH in conducting clinical trials of new medicines by accurately measuring and recording data and four core outcomes:

Optalert’s drowsiness detection glasses can enhance testing such as the standard Multiple Sleep Latency Test (MSLT) system by effectively determining real-time and continuous measures of drowsiness throughout a study.

At the core of Optalert’s drowsiness detection system is our glasses, fitted with an invisible LED camera that measures a user’s eyelid movement at a rate of 500 times per second. Changes in blink speed and eyelid movements are easily detected and then converted into a score from 0-10 that rates alertness and sleepiness.

The JDS will help pharmaceutical companies effectively measure fatigue, drowsiness and alertness in drugs during trials. Our technology can record and provide additional data on a participant’s state of both drowsiness and wakefulness.

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