Optalert

Automakers can now achieve compliance for their drowsiness monitoring system using JDS as the ground truth

Paul Zubrinich — Mon, 22 May 2023 05:20:29 +0000

Automotive Original Equipment Manufacturers (OEMs) can now achieve both EU General Safety Regulation (GSR) compliance and European New Car Assessment Programme (Euro NCAP) assessment using Optalert’s non-invasive Johns Drowsiness Scale (JDS) as the ground truth.

Numerous automotive technical services firms in Europe, including UTAC, TÜV Rheinland, and Applus+ IDIADA, have reviewed the evidence and confirmed that Optalert’s JDS is a compliant measure of drowsiness under the European GSR. All of them operate Euro NCAP accredited testing laboratories. Each of them has recognised Optalert’s JDS as a valid alternative to the KSS^[1]. This will ensure compliance with the latest European regulations and future-proof design for both Euro NCAP assessment and the anticipated stricter requirements of the 2024 European regulations.

“This recognition has been made after a thorough review of the large volume of independent scientific evidence provided by your organisation, demonstrating the effectiveness and reliability of your drowsiness detection technology,” acknowledged UTAC’s Head of Technical Expertise and Vehicle Regulation Department, Céline Vallaude.

Optalert’s objective JDS is non-invasive and passively detects the driver’s impairment from drowsiness via their eyelid movements. It is the most accurate measure of its kind, bringing to the automotive market the most state of the art science and research available in drowsiness monitoring. Until now, the primary ground truth for testing drowsiness monitoring systems was the Karolinska Sleepiness Scale (KSS). This involved training the driver and asking them how tired they were every five minutes, inadvertently rousing them and invalidating the test. OEMs have been surprised and frustrated when their systems performed drastically differently once moving from test conditions to real world driving. Optalert’s JDS will minimise these frustrations, making the transition seamless.

This clears the way for both OEMs and tier 1 suppliers to either integrate Optalert’s drowsiness measurement technology via a software development kit (SDK) into their driver monitoring system (DMS) or occupant monitoring system (OMS), or validate their own drowsiness detection technology using Optalert’s JDS, a scientifically validated objective measure of drowsiness.

It is heartening to see the industry moving away from the imprecise and subjective KSS to the more accurate, reliable, and objective JDS. The JDS is a superior neurological biomarker that directly quantifies impairment from drowsiness. It requires no driver interaction, ensuring it does not bias the measurement.

Download the complete reports below:

UTAC: Letter endorsing the JDS
Applus+ IDIADA: Driver Drowsiness Metrics for DDAW and Euro NCAP
TÜV Rheinland: Confirmation letter from TÜV Rheinland
Others: Contact us to get more details about other technical services firms that have confirmed compliance outside of the public domain.

[1] as defined in the European Union Commission Delegated Regulation (EU) 2021/1341 of 23 April 2021 (part 2 clause 5.2)

What is drowsiness and how can it be measured?

Paul Zubrinich — Mon, 15 May 2023 04:04:20 +0000

When we commonly speak of drowsiness, we may use a range of terms interchangeably, such as fatigue, tiredness, or sleepiness. In common speech, this is fine. But for the purposes of understanding the underlying science, we need to be more precise around what each of these words mean.

Drowsiness is not fatigue

Fatigue is defined as a reduction in the efficiency of a muscle or organ after prolonged activity. It occurs after strenuous physical exercise or labour. If you lie on the couch after intense exercise, you regain energy.

Drowsiness emerges in the continuous state between being asleep and awake. And when drowsiness builds up, rest leads to sleep. If a drowsy person lies on the couch, they will nod off.

Drowsiness is physiological in nature

It is important to understand that drowsiness is not a feeling. It is a neurological state with a physiological process behind it.

There are two competing drives that determine if you are drowsy: the sleep drive and the wake drive. We can picture them like a seesaw. It shifts one way or the other as we spend time asleep or awake. If the sleep drive outweighs the wake drive, you get drowsy and eventually fall asleep.

Here is a quick overview of the mechanisms at play.

Sleep drive

Time awake

Throughout the day adenosine builds up in the brain, slowly dripping into our sleep bucket. It binds to neurons and slows down their activity. When we go to sleep we take our bucket of adenosine and tip it out.

Prior sleep

If you have poor sleep it can accumulate between days, commonly referred to as your sleep bank. Some people refer to this as a “sleep debt”. The adenosine can accumulate between days with poor sleep hygiene.

Time of day

There is another effect and that is time of day. There is a melatonin tap that drips into your sleep bucket as your core body temperature drops, particularly between 2:00 and 4:00 a.m.

Wake drive

What stops you getting drowsy is your wake drive. This is driven by arousal: visual stimuli, smell, taste, and also mental stimulation.

These are all important in understanding drowsiness in driving scenarios.

You are unlikely to have a drowsiness-related accident when driving through a new city, or in a built-up area with a lot of decisions.

Take the same person and put them onto a long, boring stretch of road and you have an increased risk.

Drowsiness is expressed biologically in two ways

There are two aspects of drowsiness that can be measured:

The Karolinska Sleepiness Scale (KSS) measures subjective tiredness. It has major issues in DMS applications because of its poor resolution and weak correlation with impairment.
Optalert’s Johns Drowsiness Scale (JDS) quantifies cognitive impairment due to drowsiness. It is the only clinically proven neurological biomarker for predicting performance failure in a driver.

How can we measure tiredness and impairment?

The most common measurement of subjective tiredness used in driver monitoring systems is the Karolinska Sleepiness Scale (KSS). This involves asking a subject how tired they are on a scale of 1 to 9 (see table).

The main issues with the KSS are:

As a subject becomes more impaired, their ability to assess tiredness also becomes impaired.
It is not stable over time – my “7” last month may not be the same as my “7” this month.
It varies between subjects – your “7” may differ from my “7”.
It is extremely low resolution – only two values, “7” and “8”, are of interest to developers of driver monitoring systems. This is not a fine enough resolution to detect drowsiness in advance of a high-risk scenario.

Measuring impairment is the more useful approach for predicting a performance failure in a driver. Optalert’s Johns Drowsiness Scale (JDS) is a measure of impairment that Harvard Medical School has deemed commensurate with gold standard laboratory measures. It involves tracking eyelid movements (what is called “blepharometry”) and calculating a composite measure involving 64 characteristics of this signal. This is the best predictor of a performance failure and is therefore the best measure of impairment.

In the lab, we measure performance failures with the Johns Test of Vigilance (JTV), which evaluates the rate at which a person responds to a visual stimulus within two seconds. As a subject becomes more impaired from drowsiness, we can precisely measure the degradation in their ability to respond to visual stimuli. On the road, the most common impairment metric is wheels out of lane.

The JDS is the most accurate predictor of these performance failures both in the lab and on the road.

Extremely alert
Very alert
Alert
Fairly alert
Neither alert nor sleepy
Some signs of sleepiness
Sleepy, but no effort to keep alert
Sleepy, but some effort to keep alert
Very sleepy, great effort to keep alert, fighting sleep

How can Optalert help you with measuring drowsiness?

If you’re in the mining, transport, or fleet industries, visit our Mining & Transport page to get an overview of our product suite and how it can help you reduce risk, increase productivity, and manage fatigue and drowsiness across a fleet of drivers.

If you’re in the automotive industry, visit our Automotive page and learn about how you can integrate our drowsiness measurement technology via a software development kit (SDK) into your driver monitoring system (DMS).

Measuring Driver Drowsiness – An interview with Paul Zubrinich

Paul Zubrinich — Thu, 09 Mar 2023 02:11:55 +0000

What is Optalert’s experience in measuring drowsiness in the field?
How do we see this technology reaching maturity in the automotive sector?
What is the difference between objective and subjective measures of drowsiness?
How does Optalert see drowsiness measurement evolving in the future?

In the lead-up to the InCabin conference in Phoenix next week, our CMO Paul Zubrinich discussed these questions and a lot more with Carl Anthony from AutoVision News.

DVN Exclusive Interview: Optalert

Ryan — Sun, 20 Nov 2022 12:56:16 +0000

Optalert has more than 20 yearsu2019 expertise in drowsiness, developed primally in their work for the mining industry, wherein the equipment and vehicles; the payloads; the operator cognitive loads, and the consequences of an accident caused by drowsiness are all enormous. Thatu2019s the demanding environment in which Optalert has grown their know-how.

Follow the link below to access DVN’s exclusive interview with Optalert CTO, Simon Block.u00a0

Optalert presents at InCabin Conference, Brussels

Ryan — Wed, 03 Aug 2022 21:19:55 +0000

Join us at InCabin 2022 and hear from Dr Trefor Morgan, Optalert General Manager – Research and Development, who will be delivering a session on Measuring and Demystifying Drowsiness.

Session Synopsis

If done correctly, drowsiness can be quantified from its early stage through to the late stages. There is a biological based change that occurs in the transition from alertness to sleep in everyone. This drowsiness indicator has been proven independently in multiple sleep studies.

In this presentation, we will discuss the recent convergence of technology and the changes in the regulatory and safety landscape that now makes it possible to measure drowsiness in passenger vehicles.

We will describe the importance of the right “Ground Truth” in the development of any drowsiness detection system.

The benefits of objective measurements of drowsiness extends beyond a person’s state of mind at a single point in time. Recent advancements in cameras, image processing, facial feature extraction, and Advanced Driver Assistance Systems (ADAS) have made it possible to interact with the driver and their environment directly. In this presentation, we will also describe a multi-stage approach to the application of countermeasures. This ensures driver comfort is preserved while prolonging the duration of safe driving by introducing tiered levels of countermeasure intensity that is best suited to remedy the various stages of driver drowsiness.

Program Details

Interest for in-cabin monitoring and intelligent interior technologies is soaring. Driven mainly by forthcoming regulations and market demand for improved safety, convenience and comfort for driver and passengers.

Applications for safety, comfort and productivity will be enabled by sensors, processing hardware, AI software and algorithms, and HMI & UI design. The InCabin community brings together experts from across all these technical disciplines and the whole supply chain to drive innovation and product development.

Date: 15 September 2022
Location: Autoworld, Brussels, Belgium
Tickets: auto-sens.com/incabin/

Optalert Drowsiness Mini-Series: Part Five

Ryan — Mon, 27 Jun 2022 21:25:04 +0000

Countermeasures

In the last episode, we discussed how an objective drowsiness measure is implemented in the field. We also briefly touched on techniques called countermeasures that can temporarily alleviate drowsiness. In this episode, we first talk about the way drowsiness systems are built today and their pitfalls. We then define countermeasures and discuss how they can be used to extend safe drive time.

What are countermeasures? Countermeasures, also known as interventions (Euro NCAP) are actions that can be undertaken by a person or programmed into a car’s Advanced Driver-Assistance Systems (ADAS) to prevent further harm to the driver and other road users. Countermeasures are ranked based on their intensity. Early stages can relieve a person’s drowsiness levels by providing audio/visual indicators that a person is drowsy, whereas end stages are intended for unresponsive drivers where an automated safety manoeuvre (also known as the Minimal Risk Manoeuvre or MRM) is executed to ensure the safety of all road users.

With modern advancements in Advanced Driver-Assistance Systems (ADAS), cars can now be programmed to provide a multitude of countermeasures to a driver when necessary. However, in their present forms, many drowsiness detection systems, regulations and assessment programs classify drowsiness as a simply defined yes or no rather than a state of continuum. As and when the Driver Monitoring System (DMS) indicates that a driver is drowsy, the car would have to produce all countermeasures. This could have adverse effects:

If a driver experiencing early-stage drowsiness is served with all available countermeasures, it would annoy the driver, leading them to shut these safety systems off.
If a car only produces warnings when a driver is already experiencing late-stage drowsiness, microsleeps or sleeps, the driver might be too far down the path for the warnings to be effective.

These increasingly complex ADAS systems need an effective strategy for delivering warnings and countermeasures to drivers, and drowsiness levels can form the basis for when these measures should occur. Implementing countermeasures that are proportional in severity will not only ensure drive comfort and quality without compromising on safety, but can also be used to extend safe driving duration, as seen in our commercial fleet example. However, countermeasures work best if a person’s drowsiness level can be objectively and accurately quantified on a graduated scale, providing the resolution necessary to differentiate between early-stage drowsiness, late-stage drowsiness and everything in between. Pairing different levels of drowsiness with their appropriate countermeasures provides us with a system that can prolong safe driving time, ensuring that we arrive at our destination safely.

Once a driver’s drowsiness level is quantified, a multi-level countermeasure approach to remedy their drowsiness is as below:

Awake: No special countermeasure required from the system. All ADAS warning systems are set to the lowest level of sensitivity, giving the driver liberty to drive in comfort and at ease.
Early drowsiness onset: Preservation phase – to allow the driver to focus on the main driving tasks, the system “makes driving easy” by enabling automatic cruise control, lane maintenance, and reducing distractions through warning systems.
Early-stage drowsiness: Driver stimulation phase – the system aims to stimulate the driver to counter further drowsiness by enhancing feedback about lane keeping accuracy, applying acoustic and haptic feedback about lane departure, and amplifying kinesthetics feedback of the adaptive cruise control (stronger acceleration/deceleration).
Drowsiness: Modification of driving conditions – the system aims to introduce sensory stimulation to the driver by modifying the ambient conditions: introducing fresh air (ventilation or opening window slightly), increasing radio/entertainment system volume, and reducing cabin temperature.
Late-stage drowsiness: High stimulation phase – the system aims to increase driver engagement, “making driving difficult” to further engage the driver in the driving activities by disabling automatic cruise control, increase steering torque (resistance), reducing spring suspension, amplifying motor sound, and even introducing controlled disturbances.
Falling asleep: Protection phase – the system tries to compensate for the driver’s potential impairment by advising the driver to stop and removing limitations placed on all warnings.
Sleep: Unresponsive phase – introduction of MRM and stopping the car safely.

This approach means that drivers will only receive the countermeasures that are appropriate to their current state. Drivers experiencing early-stage drowsiness will receive more subtle countermeasures that will temporarily reduce their drowsiness level and extend safe driving time without overwhelming them with other countermeasures. Drivers experiencing mid- to late-stage drowsiness will receive more intense countermeasures to further reduce their drowsiness level, inform them of their current state and suggest that they stop and take a break whenever it is safe to do so. Drivers who are falling or who have fallen asleep will receive the harshest countermeasures to wake them up, or in the worst-case scenario, automatically pull the car over in the safest way possible. This strategy ensures that drivers are not disturbed when they are not at risk of drowsiness-related performance impairment but, when necessary, introduces countermeasures that are appropriate to the driver’s current drowsiness level.

An example of this is depicted in the figure below. Because we introduce different levels of countermeasure intensity based on the driver’s drowsiness severity (orange), each level alleviates drowsiness by a small but significant amount. Even though over time a driver’s drowsiness does keep accumulating, the compounding effect of implementing a multi-level countermeasure strategy results in an extended safe driving duration, delaying the time it takes for a driver to enter a state where they are at high risk of an accident. In this example, the multi-level countermeasure strategy successfully prevented the driver from being at high risk of an accident through the course of their drive. In addition, because each level delivers a different set of countermeasures based on its intensity, the driver does not feel annoyed by or become desensitised to the alarms. This is in stark contrast to a single level countermeasure strategy where a driver’s drowsiness level is defined as a binary outcome (blue). Because all countermeasures are delivered at a single point (be it too early, on time or too late on the drowsiness scale), the reduction in drowsiness level only occurs once or twice, and thus we do not see the compounding effect when compared to the multi-level countermeasure strategy. Consequently, drivers may become too annoyed by the alarms (and thus decide to disable them) or may become desensitised to these repetitive alarms (red marker). This inevitably results in a continued increase in drowsiness levels, placing the driver at a high accident risk for the remainder of the drive (grey).

By coupling an objective drowsiness measure with a multi-level countermeasure strategy, our system aims to strike a perfect balance between drive comfort and safety, moving us closer to a world where drowsiness-related accidents can be a thing of the past.

And that’s a wrap! We hope that you have enjoyed this drowsiness mini-series. Over the last ten weeks, we started by discussing what drowsiness is and how our body regulates it. We then talked about how drowsiness is quantified and why objective measurements are important when determining how drowsy a person is. The story then moved onto insights that we have gained from drowsiness detection systems currently implemented in commercial fleets, and finished off here with countermeasures as a tool to balance how we deliver drowsiness alerts (therefore ensuring a positive driving experience) and safety (by extending safe driving time).

THE END… roll credits

Over the course of this mini-series, we have received numerous drowsiness-related questions. We love the enthusiasm that you’ve shown about drowsiness, so we have decided to compile and address them in an epilogue! In the meantime, for those who have more questions (but didn’t know where to ask them), please send us an email at info@optalert.com. If you are developing a DMS system and want to incorporate Optalert’s advanced drowsiness monitoring, release 7.0 of our software development kit has just been announced, and will be available from 30 June 2022. For more information please email us at automotive@optalert.com, or download the release notes.

Thank you for joining us, stay safe!

Drowsiness Detection and Validation

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Optalert Automotive Drowsiness Detection – Software Development Kit Release 7.0

Ryan — Tue, 21 Jun 2022 15:44:27 +0000

Optalert is excited to announce Release 7.0 of the Optalert Drowsiness Software Development Kit. The updated SDK will be available at the end of June 2022 for Tier 1 and OEM customers and all developers of Driver Monitoring Systems for the Automotive industry. Headline features include:

Objective and predictive drowsiness protection
Now with real-time driver state detection and KSS
Compliant with Euro NCAP, GSR and worldwide measures
Rapid integration with existing Driver Monitoring Systems
Built-in filtering to better adapt to combined DMS/OMS systems
Add a scientifically validated measure to your system

For more information please contact automotive@optalert.com.

DOWNLOAD RELEASE NOTES

Optalert Drowsiness Mini-Series: Part Four

Ryan — Mon, 06 Jun 2022 18:20:23 +0000

Drowsiness in the Field

In the previous episodes, we first looked at the sleep-wake cycle and the drowsiness processes we are all subject to. The last episode addressed the different types of drowsiness measures and weighed in on why one was better than the other. In this episode, we will use a case study from our commercial fleet business to describe how an objective drowsiness monitoring system works in the field.

The success of Optalert’s drowsiness detection system stems from a solid foundation of accurate measurements of objective drowsiness in drivers. The measurements are based on eyelid movements, or blepharometry, a well-established technique that has been scientifically developed and independently validated to quantify drowsiness. These measurements are collected and sent to a device that sits in the truck, usually a tablet or phone, which analyses the data to identify levels of drowsiness in a driver. The driver can continuously see their drowsiness level, and when drowsiness is detected, the device will:

Produce an audio alarm to alert the driver;
Produce a visual alarm by continuously displaying the driver’s drowsiness risk level (a scale of 0 to 10 with 10 being extremely drowsy) in high contrast colours;
Transmit this information in real-time to a supervisor/monitoring team.

The chart below is an example of the data measured by our system working in the field. It shows the drowsiness level of two drivers over an 18-hour period. Their drowsiness levels were continuously monitored and recorded. The first driver (in blue) started their shift at around 9am and continued through to 7:30pm, with a short break around 3pm. Their drowsiness level stayed in a safe range throughout the shift. The second driver’s shift started shortly after 8pm. They already start at a higher level than the previous driver but still at a safe level at the beginning of their shift. As the night wore on, their drowsiness continued to rise. After midnight, they entered a stage where they were at risk and the Optalert system stepped in. Without this intervention it is easy to see that the driver’s drowsiness could have continued to rise to extremely dangerous levels and could have resulted in an accident.

12:15am (MN = midnight) Driver B was at medium risk of performance impairment due to early-stage drowsiness. Medium-risk audio-visual alarms were triggered.
12:30am – 2:00am Driver B experienced temporary relief from drowsiness (decrease in Drowsiness Score in red shaded area) and was safe to continue working.
2:00am Driver B was at high risk of performance impairment due to drowsiness. High-risk audio-visual alarms were triggered.
2:00am and 2:30am Driver B experienced temporary relief from drowsiness while looking for a safe place to take a break.

It is important to note, immediately after an alarm is triggered, whether medium- (Event 1) or high-risk (Event 3), Driver B’s drowsiness is temporarily alleviated (represented by a Drowsiness Score decrease), allowing the driver to either prolong their shift (Event 2) or find a safe place to stop (Event 4). This drop is created by an increase in arousal caused by the 90dB alarm in the cabin and the driver’s supervisor contacting them on their radio. This effect was discussed in “Episode 2: How your body regulates drowsiness”. Independent studies have shown that there are different types of countermeasures (such as our audio and visual alarms) that can be applied to briefly relieve a person’s drowsiness levels, thereby extending their safe driving time (more on this next week).

But does all this work? Yes, it does! As shown below, after our drowsiness detection system was implemented at a single site, the company reported an 84% reduction in road accidents over four years.

Imagine if we saw this level of accident reduction on our roads. It would go a long way in mitigating the estimated 100,000 drowsy-driving crashes that occur every year on American roads. So, how do we implement an objective drowsiness detection system in everyday cars? What other countermeasures are there that we could use? Tune in next time!

For more details see Dr Murray John’s publication titled “Assessment of ‘Sleepiness’ in Human Drug Trials: A New Perspective”. You can download a copy here.

Drowsiness Detection and Validation

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Optalert Drowsiness Mini-Series: Part Three

Ryan — Tue, 17 May 2022 16:30:26 +0000

How is Drowsiness Measured?

Last episode, the drowsiness regulation process in humans was discussed. However, to apply this understanding to real world situations we need to be able to objectively measure drowsiness levels. So how is drowsiness measured?

There are two classes of methods for measuring drowsiness: objective and subjective. Objective measures are independent of the observer, meaning they do not rely on the perception of how drowsy the subject feels or looks. In a different scenario, this may be compared to measuring temperature with a thermometer. Subjective measures are dependent on the observer’s perception, opinion and feeling of a drowsiness condition. In a similar use-case, a subjective measure would be to ask the subject how hot/cold they feel.

There are several ways to measure drowsiness objectively. These methods normally involve the use of equipment (e.g. camera) and/or a skilled technician to collect the measurements and analyse the results. For example, drowsiness may be assessed by measuring eyelid movements. Blinks are often characterised by their duration and frequency of occurrence, both of which change when a person is drowsy. These measurements are accurately and gradually scaled, providing a precise reflection of a subject’s drowsiness levels.

On the other hand, subjective measures involve asking questions from which to infer a person’s drowsiness levels. Such questionnaires have been developed over many years of research and have been widely used in sleep medicine. One example is the Karolinska Sleepiness Scale (KSS), a 9-point scale that is used to assess sleepiness levels, with 1 being extremely alert and 9 being very sleepy.

It is natural to query whether one technique is better than the other. Subjective measurements are frequently used and are handy when objective measures are not easily accessible. For example, if a thermometer is not available, asking a patient to describe how hot or cold they feel is often an acceptable indicator of a fever, unless exact measurements are required for diagnosis. Subjective measurements are also an accurate method for assessing a person’s understanding or feelings about a particular topic. For example, open-ended exam questions allow students to be creative and critical in constructing their answers, providing teachers greater scope to assess their understanding of the topic.

But what if a person’s state of mind is compromised? How much can we depend on their ability to make a judgement about their current condition and consequently, assume that their judgement is not influenced by their current situation? Picture a scene where traffic police have just pulled over a driver for swerving across multiple lanes. The officer approaches the driver, who appears dazed and smells of alcohol. Naturally, the officer would use a breathalyser to objectively assess the driver’s blood alcohol content (BAC). In this situation it would be farcical to ask the driver to assess their own level of inebriation. Not only would the driver be a poor judge of their own condition, but there is also incentive for them to underestimate their BAC to avoid being penalised!

The same can be said about drowsiness. Subjective measurements of drowsiness are cheap and easy to administer as they only involve asking a series of relevant questions. However, these measures can be problematic. Consider the following:

On a 9-point drowsiness scale, can you accurately differentiate between being a 6 or a 7?

When someone is asked to report on their level of drowsiness during the transitional phase between wakefulness and sleep, the questionnaire’s subjectivity can lead to an inaccurate indication of their drowsiness level.

Is my self-reported score of 3 equivalent to your score of 3?

Subjectivity also means the perception and interpretation of questions could differ between people when they assess their own drowsiness score; a difference that is difficult to reconcile.

How drowsy are you now? How about now? How about now? How about now?

Studies have shown that actively asking someone to self-assess their drowsiness level affects their drowsiness level. If I wanted to track your drowsiness level but asked you every five minutes how drowsy you were feeling, I am actively affecting the very thing that I am trying to measure!

Before you are allowed to make a living as a driver today, how drowsy are you feeling right now?

A self-reported score could be subject to bias depending on the situation. If someone was only allowed to continue performing an activity on the condition that they were not drowsy, they could downplay how drowsy they really felt.

Objective methods for measuring drowsiness remove the elements of human perception and bias as they involve the use of equipment and/or skilled technicians. However, there is a higher barrier of entry before these measurements can be taken, for which reason such measurements are infrequently used. However, recent advancements in drowsiness research and semiconductor technology mean that these barriers are coming down and the benefits of obtaining objective drowsiness measures (using eyelid movements) now outweigh subjective ones. Cameras that are already available on phones or in cars can now record high-resolution eyelid movements. Paired with processors containing automated algorithms that can compute drowsiness scores efficiently, a cost-effective system that can objectively detect drowsiness effectively is now possible.

Fortunately, there is an existing technology ready to be deployed in all passenger vehicles. It has been proven over the past 25 years in sleep medicine and commercial fleet drivers. Tune in next week to find out more!

For more details see Dr Murray John’s publication titled “Assessment of ‘Sleepiness’ in Human Drug Trials: A New Perspective”. You can download a copy here.

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Optalert Drowsiness Mini-Series: Part Two

Ryan — Mon, 09 May 2022 20:25:36 +0000

How your Body Regulates Drowsiness

Last episode, we uncovered the two different types of drowsiness and what they mean. This week we discuss how our body regulates drowsiness throughout the day by covering the sleep-wake cycle, a process that drives drowsiness in humans.

Our drowsiness level is regulated by the sleep-wake cycle that contains complex biological mechanisms. Simply put, there are several factors that influence where we sit on the drowsiness continuum.

Adenosine is a chemical found in the brain that increases the desire to go to sleep.
Sleep Drive represents the reservoir of adenosine that accumulates in the brain throughout the day and tips the sleep-wake cycle towards sleep.
External Arousal Factors are factors that provide an increased level of wakefulness.
Wake Drive represents the psycho-sensory drive where the arousal effect has its impact and tips the sleep-wake cycle towards wakefulness.

Collectively, these components interact continuously by inhibiting each other, with the balance between components encompassing a person’s sleep-wake cycle.

When we wake up in the morning, the sleep-wake “see-saw” is tipped towards the wake drive. Throughout the day, adenosine starts to accumulate, slowly tipping the scale toward the sleep drive. When the sleep drive outweighs the wake drive, we start to feel drowsy. We can undertake activities that act as external arousal factors. For example, standing up, watching an exciting sports event or turning up the radio when we are driving are arousal factors that would temporarily increase our wakefulness. However, a continuous build-up of adenosine would result in these activities only being effective for a short period of time. Sleep remedies this build-up by reducing adenosine levels in the brain.

Picture these two scenarios. One takes place in your car during your morning commute through the city centre, with speed limits, traffic lights and road safety cameras at every intersection. Your senses are filled to the brim as you manoeuvre through morning traffic, cyclists and jaywalkers. In this scenario, the sleep-wake “see-saw” is tipped towards the wake drive. Adenosine levels in your brain are low, meaning the sleep drive “bucket” is empty, while firm pressure is placed on the wake drive, keeping you alert and awake.

Cut scene to a different scenario: a night-time drive in the countryside with nothing visible on either side. You are driving down a long stretch of road and the only things you see are the dotted lines on the road hypnotically passing by. The radio is off as everyone else in the car is fast asleep. In this scenario, the sleep-wake “see-saw” is tipped towards the sleep drive. Adenosine has been building up throughout the day and there are no external arousal factors to tip the scales back in favour of staying awake. As a result, you start to feel drowsy, or worse, microsleep while driving.

The good news is that there are ways (known as countermeasures) that can be deployed when we start to feel drowsy. Objectively knowing how drowsy someone is at a given time is critical in deploying the right countermeasures, as they can range from the very subtle (early-stage drowsiness) to the very severe (having fallen asleep). The earlier we implement these countermeasures, the more effective they are. In other words, we need an accurate measure of drowsiness even before the driver is aware they are starting to feel drowsy. A way to accurately and objectively quantify drowsiness levels is needed and is the topic of our next discussion.

For more details see Dr Murray John’s publication titled “Assessment of ‘Sleepiness’ in Human Drug Trials: A New Perspective”. You can download a copy here.’

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