Designing Healthcare Technologies: Motivating Users by Decreasing Cognitive Load (Julie Rennecker and Shannon Halgren)

Cognitive Overhead in Healthcare

Designing Healthcare Technologies: Motivating Users by Decreasing Cognitive LoadShannon Halgren, PhDJulie Rennecker, PhD

Good morning. Thank you for joining us. When we started designing products for healthcare, several years ago, we quickly realized that what we thought we know about design, didnt always apply to healthcare. That realization interested us enough to explore this product use environment at a deeper level and to shift our design processes to meet the unique needs of these users. In this talk well share what weve learned.

Were happy to be here this morning to talk with you about cognitive loadwhich we refer to as cognitive overhead--as it applies to healthcare technology design. Well talk about what cognitive overload is, how it affects healthcare workers, and ways that we designers can minimize it through our product designs.

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HUMAN USE ERROR

Im going to begin by taking about error.

We ALL make mistakes. And we know mistakes, or what we in Human Factors call Human Use Errors, are made in the healthcare environment.

But, what factors affect when and how often human use errors are made?

How can the design of medical devices and applications minimize human use error?

These are some questions well be exploring during this presentation.

Lets begin by taking a quick look at a few documented human use errors in the use of medical technologies2

Feeding Tube and Trach Tube

http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/TubingandLuerMisconnections/ucm313275.htmFatal Tubing Mash-Ups

In healthcare, a common source of human use error are what call fatal tubing mash-ups. This is where a healthcare working connect two tubes together that should not be connected.

In this case, a feeding tube was accidentally inserted into a trach tube port and milk was delivered to an infants lungs.

The result was fatal.

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EHR ExampleLab ResultK+(3.1 mEQ/L)Dr. AIV K+ Order 1(40 meQ over 4 hr)Dr. AIV K+ Order 2(100 meQ addition to existing fluid)Dr. AAttempted to cancel first order(cancelled a similar order by mistake)PharmacyFilled Order 1Changed Order 2(too much K+, used 80 meQ)Nurse(s)Carried out Order 1 Carried out Order 2(40 meQ IV bolis and 80 meQ/L drip started}Dr. BMistakes low K + lab result as NEWTreats for low K+Patient K+(7.8 mEQ/L, normal = 3.7-5.2 mEQ/L)Shift Change36 hours later

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!(ONC, Health IT: Patient Safety Action & Surveillance Report, 2013: p.4)

And, in this example, an unfortunate string of errors related to the use of an Electronic Health Record (EHR) put a patient in serious danger, though he lived.

It began whenA gentleman had a low K level, 3.1 mili equivalients. Its just a little bit low, but does require treatment.Dr. A orders a K bolus to be delivered over a short period of timeThen he noticed the pt. already has an IV so decides it would be better to add the K to the existing IV fluid for a longer delivery time which results in greater pt. comfort (K sometimes burns).He attempted to cancel the first order, but instead cancelled a similar order by mistake.Pharm. filled the first order and changed the second order to comply with hospital policy around K treatments, but did fill it.Both orders, the bolus and the slower K administration, were carried out by the nurses.Shift change: Dr. B sees the 3.1 K level and interprets is as a new, post treatment lab value and treats for low K.K now has more than doubled. I very high or low level can stop the heart. They caught this mistake

The problem wasnt that these healthcare workers didnt care or were being careless, it was that the EHR allowed these mistakes to happen. There were several places along the way where the HER could have been more helpful in preventing this series of mistakes.

While health IT presents many new opportunities to improve patient care and safety, it can also create new potential hazards.5 poor user interface design or unclear information displays can contribute to clinician errors. (ONC, Health IT: Patient Safety Action & Surveillance Report, 2013: p.4)

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Human use errors are NOT a tiny problemInstitute of Medicine, 2000, To Err is Human44,000 98,000 deaths/year

Approximately one full 747 crashing every day

We wish that these errors were isolated incidents, but theyre not--the statistics on healthcare errors are staggering..

In 2000, the IOM published a study that got a great deal of public attention. In that report, they stated that almost 100,000 people per year died due to preventable medical errors. This is the equivalent of one full 747 crashing every day, which of course, we would hear about.

This report caused a number of new initiatives, guidelines and regulations designed to prevent human use error. 5

Human use errors are NOT a tiny problemInstitute of Medicine, 2012, Best Care at Lowest CostNorth Carolina: 18% of hospital patients are harmedMedicare: 14% of hospital patients harmedClassen et al: 33% of hospital patients harmed Estimated 86% of adverse events are unreported!

James, 2013, Journal of Patient Safety New estimate of preventable deaths: 210,000 400,000/yearPreventable incidents of serious harm: 2 8 million/year

However, fast forward a little more than a decadeSubsequent studies published in 2012 and 2013 suggest that the situation has not improvedEven worse, approximately 86% of adverse events are unreported A second study found that the original study may have underestimated the problem by as much as a factor of 4, putting the number of preventable deaths as high as 400,000 per year and the incidents of preventable serious harm are as high as 2-8 million/year.

Its difficult to determine the proportion of these errors due to medical device design, but as designers, we certainly dont want to worsen the problem.6

Why do errors like these happen?

ACT II

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Designing for the Context of Use

Standards for drugs and medical devices concentrate on safe design and production, with less attention to their safe use [in context].- Institute of Medicine, To Err is Human,1999

One recommendation from the original IOM study was that device design needed to pay more attention to the use of devices IN CONTEXT, not just whether they delivered the appropriate fluid or electric current, for example, at the correct rates.

Through our own research, weve seen that a critical component of this context is the mental workload of the healthcare user.

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Were not in Kansas Anymore! Fear of Litigation Infection Control Heavy Regulation High Risk Tasks Multi-Tasking Time Critical Tasks Mistakes = Lives High Accountability Sleep Deprivation Complicated Technology Multi-Disciplinary Teams

All of us involved in healthcare know that its a complex, high-risk world full of logistical and regulatory challenges just to name a few

So it should be no surprise that healthcare workers have a lot on their mind when theyre interacting with the devices youve designed.

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An inside look at thehealthcare environment

Trauma Patient Video

The first follows a trauma patient who arrives in the ER with a head trauma.The second will provide a look at one hospital unit through the eyes of an ICU nurse.

As you watch this first video, notice the wide number of complex micro-environments found within this healthcare facility 2 minutes

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What Did You Notice?

In this video, we saw a fairly typical trauma patient sequence beginning with the LifeFlight helicopter (or other ambulance) transferring to the ER, on to surgery, and finally to an ICU bed. What did you notice that might be important for you to keep in mind for designing healthcare devices? 12


The need for speedFrequent interruptions/multi-taskingMultiple handoffsMultiple, diverse playersLots of equipment, all with unique UIsThe pressure to get it right

Here are some things we noticed 13

An inside look at thehealthcare environment

ICU Nurse Video

The first follows a trauma patient who arrives in the ER with a head trauma.The second will provide a look at one hospital unit through the eyes of an ICU nurse.

As you watch this first video, notice the wide number of complex micro-environments found within this healthcare facility 2 minutes

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As you watch this video, try to keep track of all the different tasks and technologies this nurse works with across a few hours2 minutes

Rook ICU/Post-Op NurseRook cares for a recovering post-op patient while awaiting another from surgeryAfter working with her own patient, Rook assists in room set-up for a new admitAfter room setup, Rook gets a call another patient is arriving from surgeryThroughout the day, Rook mentors a novice CTICU nurseAfter assisting a nurse colleague, Rooks primary patient is about to arrive

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In just 2 minutes, we saw an ICU nurse perform several tasks: Care for/monitor a post-op patientSetup for a new admitReceive a second post-op patientMentor a novice ICU nurseAssist colleagueGet suppliesEtc.

What did you notice that might be important for you to keep in mind when designing healthcare devices? [TAKE THEIR COMMENTS] --- if giving talk to smaller group16


The pressure for accuracyFrequent interruptions/multi-taskingLots of equipment, all with unique UIsMultiple, diverse playersTraining during task performance

While the task details might vary from one hospital unit to the next or between hospital units and outpatient clinics, there are several recurring themes that span unit types and facilities[READ SLIDE]

Longer version/smaller groupIF MANY COMMENTS: Those are great observationshere are a few that we came up with: IF NONE or FEW COMMENTS: Here are some things we noticed: 17

Users Motivations: Comparison Across IndustriesOnline Retail

Social Media Healthcare

Need for speedMedMed to HighExtremely HighNeed for accuracyMed to HighLowExtremely HighConsequence of slow responseLowLow to MedMed to Extremely HighConsequence of errorMedLow to MedMed to Extremely HighUser stress levelLowLow to MedMed to Extremely HighEnvironmental distractionsLow to MedLow to MedMed to Extremely HighVariety of technologyLowLowExtremely High

To appreciate why designing for healthcare is so different, lets step back and take a look at User motivations when performing technology tasks in healthcare compared to performing technology tasks in other industries that we as a UX community more frequently support.18

How do we create technology for this unique user group & complex context?

READ SLIDE

To answer this question, wed like to review some basic concepts from cognitive psychology [Click!]

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Cognitive Psychology 101

Julie: and to do that Ill turn it over to Shannon, the cognitive psychologist member of our team.

Shannon: Lets spend a few minutes going back to Cognitive Psych 10120

Cognitive LoadWhitenton, K. (2013). Minimize Cognitive Load to Maximize Usability. Article published online. Cognitive Load:

The amount of mental resources required to operate the system

You can think of this as how much brain power is required to perform a task 21

3 Kinds of Cognitive Load Problem complexity- Starting an IV

- Using a defibrillator

- Conducting robotic surgeryUnrelated working memory load- Distractions

- Mental notes

- ConversationProcessing memory going towards building LTM schema- How is this IV pump different from the one I just used next door?

- How do I hold this transducer at each stage of insertion

Intrinsic Load - how complex the problem is All these examples have an intrinsic degree of cognitive demand even when performed on a simulator. Intrinsic load includes things like the number of steps to be remembered to complete the task, information that must be held in memory between steps in a task sequence, or activites/tasks that must be performed simultaneously [e.g., needing to hold down a button while inputting a new setting, needing to press two keys simultaneously, ]

Extraneous Load - load on working memory unrelated to problem at hand distractions--Audio or visual; information being remembered; participating in conversation with the patient, doctor, or family member

Germane Load - processing effort going towards the development of schema in LTM (creating connections, sequencing, rehearsing, building scaffolding)

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Cognitive Load is Cumulative+Intrinsic LoadExtrinsic LoadGermane Load+=Total Cognitive Load

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Cognitive load affects performance

Performance Drop with Cognitive OverloadMental CapacityCognitive Demand (Total Cognitive Load)Performance

Drews, FA et al (2009). Text messaging during simulated driving behavior. Human Factors, 51, 762-770.Pashler, HE (1984). Processing stages in overlapping tasks: Evidence for a central bottleneck. J of Experimental Psychology: Human Perception and Performance, 1, 395-403.Wickens, CD (1991). Processing resources and attention. In D. Damos (ed.), Multiple-task performance, p3-34. London, UK: Taylor & Francis.

As long as the cognitive demand is less than capacity/threshold, then performance is adequate.

But, the moment the demand exceeds threshold, performance suffers

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Let me show youwhat I mean

Im going to ask you to do a little experiment with me so I can demonstrate what it feels like to experience cognitive load.

For this exercise youll need to open the contact list on your mobile phone or tablet .

Go ahead and pull out your devices now and display your contact list.25

Dont Try This at Homein the ER!Procedural TaskCreate a new contact for Jane DoePhone number: 800-555-9634

Now, Im going to give you a simple procedural task to perform with this device: Please create a new contact for Jane Doe and enter her phone number.

All done? How did that go? Most of you probably found it pretty simple to do - its something youve done a least a few times before.

----Now, Im going to ask you to do that same task again, but this time, were going to add some cognitive load.

DONT start the next task until I tell you to begin.

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Distraction

Dont Try This at Homein the ER!Procedural TaskCreate a new contact for John DoePhone number: 800-555-5678

Cognitive TaskCount by 2s

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What if these were health care tasks?Procedural TaskSetup an IV

Cognitive TaskCalculate fluid rateAnswer patient questions

DistractionChild cryingOverhead page

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Humans have limited cognitive capacitybutthe cognitive demands on healthcare workers continue to increaseCapacityDemand

The ConflictPerformance

This leads us to a dilemma in healthcare.

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But what does this have to do with product design?

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The Resolution

Medical technology must be designed to require less cognitive overhead.

Product design simply can not be part of the problem. We need to contribute to the solution.

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Design Rules for Reducing Cognitive LoadBe Simple1Be Consistent5Be a Team Player6Be Helpful2Intrinsic LoadExtrinsic LoadGermane Load Be Smart Be Calm43

Weve developed a set of SIX design principles addressing the three aspects of cognitive load:[Read through list]

Now, well look more closely at each one.32


First, we need to address the intrinsic load imposed by whatever device were designing.

The two key principles here are Be Simple and Be Helpful.33

Be Simple1

The subject matter can be complex, but the UX should not be

[READ SLIDE].

One key to simplicity is34

Be MinimalLess is moreShow only what you really needGroup related informationUse a clean visual design

Be Simple1

Read slide35

Be Simple1

Be Minimal

Heres an example: Youre 10 minutes late out the door. Which would you rather use to decide if you need to grab a coat?

The example on the right is a great example of less is more - It provides only what you need

Even a visual design can be distracting36

Be MinimalLess is moreShow only what you really needGroup related informationUse a clean visual design

Be DirectCareful use of abbreviationsCareful use of iconsMake alert states obvious

Be Simple1

A second key to Being Simple is Be Direct37

Be Direct use obvious alert statesBe Simple1FusionCharts Patient Monitoring System

Patient Monitoring System by Fusion Charts

Status is clear at a glanceGraphics support rather than distractAppropriate visual heirarchy

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Be Helpful2Think guided workflows, not features

[Read slide]39

Provide GuidanceThrough the workflowNext stepsAccess to help

Be Helpful2

One of the best ways to be helpful is to provide guidance to assist the user during task performance

[read slide]40

Be Helpful2Before: Where do I start? Where can I get help?

Provide Guidance - Provide a place to start

OnOffButtonButtonButtonButtonButton

ComplexInformation DisplayStatus Display

ON

ON

ON

ONStatus Display

ON

ONLinkLinkLinkLink

Heres a conceptual example from one of our projects:

If you were a new user, where would you start? How would you get help? 41

Be Helpful2After: Guided Workflows, Grouped content

Provide Guidance - Provide a place to start

Our redesign took a guided workflow approach and provide a clear place to start and immediate access to additional help.

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Provide GuidanceThrough the workflowNext stepsAccess to help

Prevent ErrorsMake it obviousMake it easyMake it dummy-proofPrevent omissions

Be Helpful2When you are stressed out, [making it] dummy proof is better. OR Nurse

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Be Helpful2

Prevent Errors Make it dummy proof

Hungarian designer Kevin Harald Campean

http://designtaxi.com/news/360796/A-Bold-Sleek-Redesign-Of-The-First-Aid-Kit/?goback=%2Egde_63344_member_275785103#%21

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Be Helpful2

Prevent Errors Make it dummy proof

Designer: Kevin Harald Campean

Hungarian designer Kevin Harald Campean

http://designtaxi.com/news/360796/A-Bold-Sleek-Redesign-Of-The-First-Aid-Kit/?goback=%2Egde_63344_member_275785103#%2145


It isnt enough to only focus on the intrinsic load of our product.

As we saw in the video, our products will be used in complex environments, so we also need to think about helping users dealing with a heavy extrinsic load.

The key principles here are Be Smart and Be Calm.46

Technology should serve as a natural extension of our task performance rather than a barrier to overcome.

Be Smart3

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Be a Natural Extension of the userHold information in memory for the userPerform calculations for the user

of the taskProviding the right tools at the right timeRecognize errors or alert conditionsBe easy to ignore when not neededBe difficult to ignore when theres danger

Be Smart3

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Be Smart3LabK+(3.1 mEQ/L)Dr. AIV K+ Order 1(40 meQ over 4 hr)Dr. AIV K+ Order 2(100 meQ addition to existing fluid)Dr. AAttempted to cancel first order(cancelled a similar order by mistake)PharmacyFilled Order 1Rejected Order 2(too much K+, suggested 80 meQ)Nurse(s)Carried out Order 1 Carried out Order 2(80 meQ/L drip and 40 meQ IV bolis started}Dr. BMistakes lab result as NEWTreats for low K+Patient K+(7.8 mEQ/L)Normal K+ Level: 3.7-5.2 mEQ/LShift Change36 hours later

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!EHR: - Recognize patient already has fluids and suggest Order 2 to reduce pain.EHR: - Recognize unsafe levels of K+EHR: - Recognize unsafe levels of K+EHR: - Recognize unsafe levels of K+EHR: Better shift change updates & alertsImproved usability around date & time on lab results- Recognize unsafe levels of K+

Lets take a look at how the EHR could have been more helpful during this series of unfortunate events.49

Be Calm4

Provide a calm & soothing user experience

Healthcare workplaces are over stimulating and stressful environmentsThe technology, in contrast, needs to be calm50

Be AttractiveUse soothing colorsUse a neutral color paletteProvide ample white space

Be Calm4We assume if it looks nice, its a good product.- OR Nurse

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Be Attractive Pay attention to colorBe Calm4

Well use the color palette we selected for this presentation as an example. If we did our job right, you didnt even notice the colors until we pointed them out. Or, if you did notice them, it was because you liked them.52

Some might feel this color palette is more exciting, but its also is more tiring to view over long time periods53

Be Attractive Pay attention to colorBe Calm4

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A subtle color palette allows more attention to be given to alerts. This allows alerts to be less demanding themselves.54

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This color palette demands more vigilance to detect alerts.55

Be AttractiveUse soothing colorsUse a neutral color paletteProvide ample white space

Be MindfulCareful use of animationPay attention to use of audioAvoid causing alarm fatigue Be Calm4

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Be Mindful of audio and animation useBe Calm4

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Finally, we need to recognize the contribution to Germane Load made by each additional device added to the users world.58

Be Consistent5

Provide a predictable user experience routine is important

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Provide simple, consistent workflowsWithin the designAcross your product line Across similar medical devicesWith users expectations

Be Consistent5

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Within and between your product(s)

Be Consistent5

Use templates and style guides

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Within and between your product(s)

Be Consistent5Inventory interaction behaviors (alerts, modes, button states, controls, feedback, etc.)

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With users expectations

Be Consistent5Measure users mental models

Formative research techniques can be used to gather data on user expectations.

Card sorts can be used to understand users mental models 63

With users expectations and needs

Be Consistent5Interview and observe users in context

And field research can be used to gain an intimate understanding of users environment, tasks, motivations and needs.64

Be a Team Player6

Recognize that you are part of a technology team whether you want to be or not

Beyond consistency within your own product, it is important to recognize that your product is part of a technology teamwhether you want to be a team player or not!

Free clip art65

Be a Team Player6The product teams world view

Our Other Awesome ProductACME

Our Other Awesome ProductACMEOur New Awesome ProductACMECompeting ProductCompeting ProductCompeting ProductCompeting ProductCompeting ProductRelatedProductRelatedProductRelatedProductRelatedProduct

Free clip art

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Our New Awesome ProductACMEOur New Awesome ProductACMEBe a Team Player6The users world view

Competing ProductOur Other Awesome ProductACMERelatedProductRelatedProductRelatedProductCompeting ProductCompeting ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductOur Other Awesome ProductACMERelatedProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductUnrelated ProductPolicySafetyPatient ManagementStress ManagementAccuracyEfficiencyProtocolsRegulationInterpersonal RelationshipsRiskRecord KeepingFatigueHuman EmotionsDistractionsQuality

Free clip art

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Take a systems engineering perspectiveAvoid local success, global failureConsider the other technology being used in conjunction with yoursCompetitors productsOther products from your companyNon-related technology (smart phones, tablets, medical devices, EHRs, patient monitors, etc.) Each technology might have their own uniqueWorkflowsAudio soundsVisual alertsIcon sets & color palette

How will your product fit in with the existing technology?Be a Team Player6

[Ascom could be a good example here: In some facilities, the client uses their entire suite of products; in others, only the handset or only the console, etc.]68

Be a Team Player6then find a way to complement rather than compete

Study competitors, related products, industry standards, and the use environment

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Be a Team Player6Be different ONLY if you improve the global user experience.

Dont be different, just to be different.

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How do I know if my designs cognitive load is manageable?

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Evaluating Your Design for Cognitive LoadCommon methods used in uncommon waysDesign ReviewCognitive WalkthroughSimulated Use Usability TestingField ResearchCompetitive Product ReviewDirect Observation

Evaluating the cognitive load of your design doesnt require new research methods so much as attending to additional aspects of the design while using familiar methods, such as Design Reviews, Cognitive Walkthroughs, Usability testing & field research, etc.

Ill walk through a few examples to show you what I mean73

Evaluating Your Design for Cognitive LoadMinimalismAbbreviation & icon useConsistency across screens & workflows

Intrinsic LoadExtrinsic LoadGermane LoadDesign Reviews Cognitive WalkthroughGuided workflowsPaths for novice v. expert usersContextually-specific use cases (e.g., surgery, ER, home care)

Intrinsic Load

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Evaluating Your Design for Cognitive LoadSimple to useEasy interpretation of status

Obvious next stepsTo ensure workflows and content are accurate and usefulTo test audio and animation use

To ensure product is usable when used in conjunction with other technologyTo ensure product is easy to learn when experienced with other brands or past versions

Extrinsic LoadGermane LoadSimulated Usability TestingIntrinsic Load

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Evaluating Your Design for Cognitive LoadTask performance in a realistic settingSimulation lab in a medical facilityResearch lab modified to mimic use settingReal world environment

With a realistic level of cognitive loadDistractionsAmbient NoiseInterruptions (major and minor)Multi-tasking Finger or foot tapping while performing task Reading the time from a wall clock when each step of task is performed

With appropriate pre-use training

Intrinsic LoadExtrinsic LoadGermane LoadSimulated Usability Testing

Real world environment: coffee shop; subway; living room

Modified Research Lab:Room setup to mimic patient care settingEquipment placement similar to actual use

Interruptions:Answering unrelated questionsDoctor asking for a new task statPhone call/Text message

Provide Appropriate Level of Training prior to testingTeam trainingsSales Rep trainingInstructions for Use availableConsider lag time between training and task performance

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Evaluating Your Design for Cognitive LoadTask analysisWorkflowsContext analysis

Extrinsic LoadGermane LoadField Research: Pre-designCompetitive Product & Regulation ReviewIndustry standardsRegulatory guidelines

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Considering Cognitive Load During Design ValidationIntrinsic LoadExtrinsic LoadGermane LoadBe Simple & HelpfulDesign Walkthrough / Heuristic EvaluationCognitive WalkthroughIterative Usability Testing

Be Smart & CalmField ResearchTask AnalysisIterative Usability TestingBe Consistent & a Team PlayerCompetitive Product ReviewRegulation and Guidance ReviewDesign ReviewSimulated Use Usability TestingDirect Observation

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Sounds good, but how am I going to remember all this?

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Checklist for Reducing Cognitive Load Through DesignFor a copy, email one of us orsee me after the session.

[email protected]

[email protected]

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Design can save lives.

The bottom line.

What you [designers] do matters. Medical device design can mean the difference between injury & safety, life & death.Your designs can be the difference between a manageable level of cognitive load81

Manageable level of cognitive load

where your users feel like super heroes 82

Unmanageable level of cognitive load

or an unmanageable level of cognitive load which leads to human use error.

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THANK YOU!Julie Rennecker, PhD RNPrincipal ConsultantThe Management Doc, [email protected]

Shannon Halgren, PhDChief HF/UX ConsultantSage Research & Design, [email protected]

We hope this has been helpful. Be well & do good work.

. And now well take any questions.

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ReferencesDrews, FA et al (2009). Text messaging during simulated driving behavior. Human Factors, 51: 762-770.Eriksen, CW & Eriksen, BA (1974). Effects of noise letters upon the identification of a target letter in a non-search task. Perception and Psychophysics, 16: 143-149.Gasper, JG et al (2014). Are Gamers Better Crossers? An Examination of Ation Video Game Experience and Dual-task Effects in a Simulated Street Crossing Task. Human Factors, 56(3): 443-452.Horsky, J et al (2003). A framework for analyzing the cognitive complexity of computer-assisted clinical ordering. J of Biomedical Informatics, 36: 4-22.Institute of Medicine (2000). To Err is Human: Building a Safer Health System. Committee on Quality of Health Care in America, LT Kohn, JM Corrigan, & MS Donaldson (eds). Washington, DC: National Academies Press.Institute of Medicine (2012). Best Care at Lower Cost: The Path to Continuously Learning Health Care in America. M Smith et al (eds.), Committee on the Learning Health Care System in America. Washington, DC: National Academies Press.James, JT (2013). A New, Evidence-based Estimate of Patient Harms Associated with Hospital Care. J of Patient Safety, 9: 122-128.Katidioti, I and Taatgen, NA (2014). Choice in Multitasking: How Delays in the Primary Task Turn a Rational into an Irrational Multitasker. Human Factors, 56(4): 728-736.Kalyuga, S (2011). Informing: A Cognitive Load Perspective. Informing Science: the Intl J of an Emerging Transdiscipline, 14: 33-45.Pashler, HE (1984). Processing stages in overlapping tasks: Evidence for a central bottleneck. J of Experimental Psychology: Human Perception and Performance, 10: 395-403.Pashler, HE et al (2001). Attention and Performance. Ann Rev Psychology, 52: 629-651.Posner, MI & Petersen, SE (1990). The Attention System of the Human Brain. Ann Rev Neurosci, 13:25-42.Wickens, CD (1991). Processing resources and attention. In D. Damos (ed.), Multiple-task performance, p3-34. London, UK: Taylor & Francis.Wicklund, M., Kendler, J. and Strochlic, A. (2011). Usability Testing of Medical Devices. CRC Press, Taylor & Francis Group, Boca Raton, FL.

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