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.
What's the Science Behind Impairment Testing?
Cognitive Processes Essential to Workplace Safety and Performance
Impairment tests typically measure the functionality of a combination of several cognitive information processes that are essential to the ability of workers to perform their tasks safely, efficiently, and without error (Zhang, 2019):
- Perception: Recognition and interpretation of sensory stimuli (sight, smell, touch, hearing, etc.).
- Memory: Short-term/working memory (limited storage), and Long-term memory (unlimited storage).
- Attention: Ability to sustain concentration on a particular object, action, or thought, and ability to manage competing demands in our environment.
- Processing speed: Ability to quickly process incoming visual stimuli, to understand spatial relationship between objects, and to visualize images and scenarios.
- Executive Functions: Abilities that enable goal-oriented behavior, such as the ability to
plan, and execute a goal. These include: - Flexibility: The capacity for quickly switching to the appropriate mental mode.
- Theory of mind: Insight into other people’s inner world, their plans, their likes and dislikes.
- Anticipation: Prediction based on pattern recognition.
- Problem-solving: Defining the problem in the right way to then generate solutions and pick the right one.
- Decision making: The ability to make decisions based on problem-solving, on incomplete information and on emotions (ours and others’).
- Emotional self-regulation: The ability to identify and manage one’s own emotions for good performance.
- Sequencing: The ability to break down complex actions into manageable units and prioritize them in the right order.
- Inhibition: The ability to withstand distraction and internal urges.
Fatigue vs. Alcohol Intoxication in the Workplace
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.
What Impairment Testing Measures
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.
Impairment Testing Baselines
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.
More Resources:
Analyzing Fit for Work in the Top 5 Most Common Workplace Accidents
How AlertMeter® Fits into a Workplace Drug and Alcohol Testing Program
What is Occupational Impairment? Here's Why Drug Testing Isn't Enough
What Occupational Impairment Tests are Available Today
Will Employees Buy-in to an Impairment Test Program
69% of Your Employees Are Drunk at Work
Signs of Impairment in the Workplace
Workplace Impairment Policy to Reduce Errors and Increase Productivity at Work
How AlertMeter® Fits into a Workplace Drug and Alcohol Testing Program
NSC Impairment Detection Technology & Workplace Safety Report
Recognizing Impairment in the Workplace
What are the Benefits of Cognitive Impairment Testing?
What Occupational Impairment Tests are Available Today
Impairment in the Workplace - How Does Impairment Testing Compare to Drug Testing?
Is Workplace Impairment Testing Right for Your Company?
References
Basner, Mathias, and Joshua Rubinstein. “Fitness for duty: a 3-minute version of the Psychomotor Vigilance Test predicts fatigue-related declines in luggage-screening performance.” Journal of occupational and environmental medicine vol. 53,10 (2011): 1146-54. doi:10.1097/JOM.0b013e31822b8356
Butler B, Tranter D. Behavioral tests to assess performance. In: Macdonald S, Roman P, editors. Research Advances in the Workplace: Volume 11. Drug Testing in the Workplace. New York: Plenum Press; 1994. pp. 231–255. [Google Scholar]
Czeisler MÉ , Lane RI, Petrosky E, et al. Mental Health, Substance Use, and Suicidal Ideation During the COVID-19 Pandemic — United States, June 24–30, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1049–1057. DOI: http://dx.doi.org/10.15585/mmwr.mm6932a1external icon.
Dawson, D., Reid, K. Fatigue, alcohol and performance impairment. Nature 388, 235 (1997). https://doi.org/10.1038/40775
ECA. (2016). Problematic substance abuse in aviation: Testing & peer support programmes. European Cockpit Association AISBL. Retrieved from https://www.eurocockpit.be/sites/default/files/problematic_substance_
use_prevention_in_aviation_eca_position_pp_15_1120_f_1.pdf
Fell, James C, and Robert B Voas. “The effectiveness of a 0.05 blood alcohol concentration (BAC) limit for driving in the United States.” Addiction (Abingdon, England) vol. 109,6 (2014): 869-74. doi:10.1111/add.12365
Lamond N, Dawson D. "Quantifying the performance impairment associated with fatigue." J Sleep Res. 1999 Dec;8(4):255-62. doi: 10.1046/j.1365-2869.1999.00167.x. PMID: 10646165.
Maltby, L. (2010). Impairment testing—Does it work? National Workrights Institute. Retrieved from http://www.workrights.org/nwi_drugTesting_impairmentTesting.html
Seijts, G. H. & O’Farrell, G. (2005). Urine collection jars versus video games: Perceptions of three stakeholder groups
toward drug and impairment testing programs. Journal of Drug Issues 35(4): 885–916. doi:10.1177/002204260503500411
Zhang, Jiawei. "Cognitive functions of the brain: Perception, attention and memory." arXiv preprint arXiv:1907.02863 (2019).
