Workplace impairment is a serious and sometimes confusing topic. The causes of impairment are varied, the effects mixed and remediation efforts, until now, have been difficult to implement.
This guide to Workplace Impairment is designed to answer your questions and get your organization on the right track.
Cognitive Processes Essential to Workplace Safety and Performance
The cognitive effects of impairment due to drug or alcohol intoxication are well-researched and widely recognized. Difficulty walking, blurred vision, slurred speech, slowed reaction times, impaired memory, impaired judgment, and decision-making, are a few of the most common symptoms.
Less widely recognized is the fact that impairment due to fatigue often manifests in the same way. Since humans are naturally more vulnerable to fatigue through sleep loss, emotional distress, illness, dehydration, medication use, etc., the levels of impairment and consequent workplace safety risk attributable to fatigue often exceed that of intoxication.
One study compared the cognitive effects of alcohol impairment to fatigue impairment by measuring participants' performance on a variety of cognitive impairment tests.
They found that after 24 hours of sustained wakefulness, participants experienced a performance decrement equivalent to impairment due to a BAC of 0.05. (It takes at least four drinks for an average 170-pound male to exceed 0.05 BAC in 2 hours on an empty stomach and three drinks for a 137-pound female (Fell, Voas).)
The study also found that performance decrements varied depending on the complexity of the cognitive task. For example, after only 13 hours of sustained wakefulness, the level of impairment on reasoning speed matched that of a person with a BAC of 0.05.
Although comparable to the dangerous effects of intoxication, impairment by fatigue is often more subtle and difficult to identify.
Thus, impairment tests combine a variety of simple and complex tasks to serve as a finer measurement of impairment due to both intoxication and fatigue.
The AlertMeter®, for example, combines perception, decision-making, accuracy, speed, shape recognition, hand-eye coordination, and memory all in one 60-second test.
The test involves scanning a phone or tablet screen to recognize any differences amongst a variety of presented shapes. The user must determine if all the shapes are the same, or if one of the shapes is different. This measures the potential impairment of the perception, pattern recognition, and decision-making processes of the brain. Once reaching a decision, the user must tap the shape that is different or tap a button indicating that all the shapes are the same.
This challenges the information processing speed, accuracy, response time, and hand-eye coordination processes of the brain.
Finally, on several screens, they are asked to remember a shape and recall it several screens later. This challenges the short-term memory function of the brain as well as measuring users' ability to multi-task or switch quickly between tasks. The inclusion of a memory component in the test is especially effective at identifying cannabis-induced highs in real-time, a feat no other form of drug or impairment testing has accomplished.
The science is clear that a person impaired by intoxication or fatigue will experience significant challenges in carrying out these processes. Thus, the inability to perform on the AlertMeter® impairment test is a strong indicator of user impairment due to intoxication by any substance and fatigue due to any cause.
Since human cognitive function also includes learning, "individual rolling baselines" are a central component of all successful impairment tests:
"The [impairment] test’s scoring should adjust for the learning that occurs as employees perform the test repeatedly... Typically, this potential problem is handled by establishing a baseline performance level...This baseline is adjusted regularly to compensate for continued improvement due to practice or learning. To assess performance on any given day, the employee’s score is compared with his or her adjusted baseline score" (Butler, Tranter).
Impairment testing baselines also help personalize user performance and scoring in a way that controls for external variables such as intelligence, language, education level, or familiarity with technology. Essentially, this means that it doesn't matter how well or poorly a user performs on the test. Instead, what is being measured is the user's deviation from his/her typical cognitive behavior. Typically, there is a slight deviation in everyone's cognitive performance from day-to-day and even from morning to afternoon. Significant deviation, however, has been shown to be an accurate indicator of significant cognitive impairment.
For example, the AlertMeter's® scoring algorithm and its “rolling baseline” adjusts over time as users’ familiarity and performance with the test improves. If a worker is impaired, their score will fall significantly outside their baseline as shown in the AlertMeter® results graph below.
Note: AlertMeter® was validated by a NIOSH-funded 2009 scientific study, and further proven through other research studies in addition to 75+ million man-hours.
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