Chapter 27: Cognitive & Neurologic Function in Older Adults

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Welcome back to The Deep Dive.

Today we are tackling something that I think a lot of us take for granted, but it is actually the most complex piece of machinery in the known universe.

We're this web of tissue that literally defines who we are, how we move, how we feel.

But the big question we're looking at today is, what happens to that machinery when it gets old?

It is the ultimate question for gerontology, isn't it?

And specifically, we're diving into Chapter 27, Cognitive and Neurologic Function from Gerontologic Nursing, the fifth edition by Sue E.

Minor.

Right.

And just to set the stage for our listeners, our mission today is pretty specific.

We're imagining our listener is a nursing student.

Maybe they're encountering gerontology for the first time.

They've opened this massive textbook.

They see Chapter 27 and they see diagrams of neurons and lists of drugs, and they're feeling a little overwhelmed.

Our job is to decode this.

We want to translate that dense physiological and clinical text into a clear, logical narrative.

We want the what, the why, and the how of nursing care.

Exactly.

We aren't just reading the book to you.

We're going to connect the dots between the anatomy, the hardware, and what you actually see

So give us a roadmap.

Where are we going today?

We have a lot of ground to cover.

We're going to start with the normal age -related changes, what happens to the hardware of the brain.

Then we're going to look at the three Ds, depression, delirium, and dementia.

That's a huge section.

We'll move into major neurologic conditions like Parkinson's and stroke, and we'll finish with the nurse's toolkit, how do you manage behaviors, and what about the pharmacology?

Okay, let's jump right in.

Section one, the hardware.

I feel like there's this common assumption that getting old just means losing brain cells.

Like you hit 65 and your neurons just start dying off in mass numbers.

Is that accurate?

That is actually a widespread myth, and the text acts very quickly to correct it.

We used to think aging was just mass extinction of neurons, but modern imaging shows us that while there is some loss, it's not as extensive as we believed.

The primary issue isn't that the neurons disappear, it's that they change shape and function.

So they're still there, but they look different.

Exactly, they shrink.

The actual cell body decreases in size, but more importantly, they accumulate gunk inside.

The text describes the accumulation of lipofusion.

Lipofusion, that sounds like a technical term for rust.

It's essentially cellular debris.

It's a dark fluorescent pigment that builds up over decades.

You also see the development of neuritic plaques outside the cells.

So imagine an engine that's been running for 80 years.

The pistons are still there, but there's carbon buildup and the oil is sludge.

And I assume that affects how the engine runs.

Precisely.

This structural change hits the neurotransmitters.

These are the chemical messengers, acetylcholine, dopamine, serotonin.

As we age, the enzymes that synthesize these chemicals become less efficient, and the receptor sites on the receiving neurons degrade.

So if I'm understanding this right, you have a shrinking neuron sending out fewer chemical messengers into a gap that is cluttered with debris.

That is a perfect visualization.

And the result is a change in synaptic transmission.

The signal still gets there, but it takes the scenic route or it meets resistance.

This is why we see a slowing of nerve impulse transmission.

Clinically, this manifests to slower reaction times.

It's not that the person can't process the information, they just need a few more milliseconds to do it.

Okay, let's double click on sleep.

Because you mentioned the reticular activating system, the RAS.

I remember that from Anatomy 101.

But refresh my memory.

Physiologically, what is the RAS actually doing?

Think of the RAS as the brain's gatekeeper.

It's located in the brainstem and it's a net of nerve cells that filters incoming stimuli.

When you're awake, it's letting the noise through.

When you sleep, it suppresses that input so your cortex can rest.

In aging, we see a physical deterioration in those neurons in the brainstem.

The gatekeeper gets a little sloppy.

So it's not filtering as well.

Exactly.

It lets more noise through, which leads to frequent awakenings.

But the bigger story here is the architecture of the sleep itself.

We used to think sleep was just sleep, but minor breaks it down into distinct stages and they get hit differently by aging.

Right.

You have REM and non -REM.

Correct.

Non -REM has four stages.

Stages one and two are light sleep.

Stages three and four are deep, slow -wave sleep.

Here is the crucial physiological insight.

Stages three and four are where physical restoration happens.

That's where growth hormone is released.

That's where tissue repair happens.

And that's the deep recharge.

That is the battery recharge.

And the data shows that in older adults, stage three and four sleep is drastically reduced.

In some people over 90, it's virtually So if they lose the physical repair stage,

that has to impact how their body heals from illness.

100%.

If you have a 90 -year -old patient recovering from surgery and they literally cannot enter deep restorative sleep, their healing trajectory is compromised.

And to make it trickier, while deep sleep vanishes, stage one, that transition sleep where you are barely under actually increases.

So they're spending more time in the shallow end of the pool.

Exactly.

They feel like they slept, but they didn't rest.

They report fragmented sleep.

And this is where the nurse has to be a detective because if a patient says, I wake up at 4 a .m.

every day, that might be normal aging, a shift in the circadian rhythm called phase advance.

But if they're falling asleep while eating breakfast, that is pathologic hypersomnia.

That's not aging.

That's a red flag.

That is a key takeaway.

Naps are okay.

Falling asleep in your soup is not.

Let's move to the inputs, the senses.

The brain is only as good as the data gets, right?

What happens to the input devices?

They degrade, and this creates an input problem.

Let's look at vision first.

The lens of the eye thickens in yellows.

It becomes less elastic.

This leads to presbyopia, the inability to focus on close objects.

But the yellowing is interesting.

It changes color perception.

Everything looks a little sepia -toned.

Essentially.

The yellow lens filters out shorter wavelengths of light.

This means the ability to distinguish between blue, green, and violet shades fades.

If you are a nurse teaching a patient to sort pills, and you say, take the blue one, they might literally not be able to see the difference between the blue and the green pill.

That is a massive safety issue.

It is.

And because the lens thickens, less light hits the retina.

An 80 -year -old needs about three times as much light to read as a 20 -year -old.

They also struggle with glare recovery.

Driving at night becomes dangerous because oncoming headlights blind them for longer.

And hearing, I know we joke about hearing.

But what is the physiology there?

It's called presbycusis.

This is sensorineural hearing loss.

The hair cells in the cochlea degenerate.

But it's not just turning the volume down.

It is frequency specific.

You lose the high frequencies first.

What does that sound like?

Well, human speech relies on high frequencies for consonants.

Sounds like F, G, S, Z, T, S, Those are high -pitched percussive sounds.

Vowels are low -pitched.

So the older adult hears the vowels but loses the consonants.

So did you take the fish?

Exactly.

Speech becomes muddy.

So if you are a nurse and you are shouting at a patient, did you take your pills, the TKPS might all be dropping out.

Shouting usually raises the pitch of your voice, which actually makes it harder for them to hear.

You need to lower your pitch and speak clearly, facing them so they can lip read.

And briefly, taste and smell.

The number of receptors drops.

But again, think safety, not just culinary enjoyment.

If you can't smell, you can't smell smoke.

You can't smell a gas leak.

You can't smell that the milk has gone bad.

It becomes a safety hazard and a major cause of appetite loss.

So we have slower processing, lighter sleep, and bad data coming in from the senses.

How does this affect actual thinking?

Is forgetfulness normal?

This brings us to the text that emphasizes that intelligence doesn't just vanish.

There is a difference between fluid intelligence and crystallized intelligence.

Break those down for us.

Fluid intelligence is biologically determined.

It's processing speed, learning new things quickly, multitasking.

Think of it as how fast the librarian can run to get a book.

That declines with age.

But crystallized intelligence, that's the library itself.

Long -term memory, wisdom, vocabulary, knowledge accumulated over a lifetime.

That often remains intact or even improves.

So a healthy older adult might take longer to learn a new computer system, but they can explain the history of the company better than anyone.

Precisely.

They need time.

That's the key for nurses.

Allow time for processing.

Don't rush the history taking.

The file is in there.

The librarian just walks a little slower now.

Okay, so if we know things change, we need to be able to measure it.

Section two is about toolkit assessment.

Why is establishing a baseline so important?

Because older adults have what we call reduced homeostatic reserve or homeostenosis.

They can't bounce back as easily.

If you don't know what their normal is, you can't tell when they've dropped.

If a patient comes in and they're a little confused, is that their baseline dementia or did they just develop a urinary tract infection an hour ago?

You need a baseline to detect reversible conditions.

And how do we assess function?

The text talks about ADLs and IADLs.

Right.

ADLs are activities of daily living the basics.

Bathing, dressing, toileting, eating.

These are the last to go.

IADLs are instrumental activities of daily living, paying bills, shopping, cleaning the house, using the phone.

Why the distinction?

Because IADLs require higher level cognitive function.

They are the early warning system.

You will see someone whose house is getting messy or who isn't paying bills long before they stop bathing themselves.

If you only check ADLs, you might miss the early stages of decline.

Now, the text lists a few screening instruments, the DSRS, the SLOMS, the MiniCog.

I want to circle back to the MiniCog.

You mentioned the clock drawing test.

I'll be honest, when I first saw this, I thought, really?

We're diagnosing dementia by asking someone to doodle a clock.

It seemed too simple.

It feels simple, but if you unpack the cognitive load required to do it, it's actually a stress test for the brain.

Think about the command.

Draw a large circle, put the numbers in, and set the hands to 10 past 11.

Okay, break that down for me.

What is the brain actually doing?

Step one is verbal understanding.

The auditory cortex has to hear the instruction, and Wernicke's area has to decode clock and 10 past 11.

If they just stare at you, the breakdown might be there.

Then they have to draw the circle.

Right.

That's visual spatial planning.

They have to visualize the shape and execute the motor command.

But the real test is the numbers.

This is executive function and abstract reasoning.

You have to plan ahead.

You have to know that 12 goes at the top, 6 at the bottom, and you have to space the other numbers so they fit.

I've seen patients write one, two, three, and by the time they get to five, they're already at the bottom of the circle.

Exactly.

That's a planning deficit.

It shows the frontal lobe isn't looking ahead.

And then the final trap, 10 past 11.

A specific type of error happens here called stimulus bound response.

The patient hears 10 and draws a hand pointing at the 10.

They lose the abstract concept that 10 past means the number two.

Wow.

So a simple sketch actually tests hearing, language, motor skills, spatial planning, and abstract reasoning all at once.

In less than a minute.

That's why it's the gold standard for rapid screening.

If that clock is abnormal, if the numbers are squished or the hands are wrong, it is highly predictive of cognitive impairment.

And for a nursing student, it's a tool you can use anywhere.

You don't need a computer.

You just need a napkin and a pen.

Okay.

Let's move to the heavy hitters.

Section three, the three D's, depression, delirium, and dementia.

The text has this table 27 -2 that contrasts them.

This seems like peak NCLE -X exam material.

Absolutely.

Differentiating these three is probably the most critical skill for a gerontologic nurse.

You cannot treat them if you can't tell them apart.

Let's start with depression.

The text calls it the great masquerader.

Why?

Because in older adults, depression can look exactly like dementia.

It's called pseudo dementia.

The patient might have memory loss, apathy, difficulty concentrating, and slowed speech.

If you assume it's Alzheimer's, you miss the chance to treat a reversible condition.

If you treat the depression, the memory often comes back.

And they don't always walk in crying, right?

We have this image of depression as weeping.

Rarely in this demographic, older adults present with somatic symptoms.

They complain about their body.

My stomach hurts.

I'm constipated.

I'm so tired.

My back aches.

They don't say I'm sad.

They express their psychic pain through physical language.

There is a really alarming statistic in the text regarding suicide.

Yes.

White men over age 85 have the highest suicide rate of any demographic.

It's a tragedy that often goes unnoticed.

The risk factors are loss of a spouse, physical illness, and living alone.

Nurses need to be hypervigilant.

If an older man gives away his prized possessions, puts his will in order, or stops taking his meds, that is a massive red flag.

Next, delirium.

How is this different from dementia?

The key word is acute.

Dementia is a slow, gradual slope.

Delirium falls off a cliff.

It happens over hours or days, and it fluctuates.

One minute they are lucid, answering your questions.

Ten minutes later, they are hallucinating or picking at the air.

The text calls it a medical emergency.

It is.

Think of delirium as the brain's check engine light flashing red.

It's a sign that something is physically wrong elsewhere in the body.

Common causes, what we call vulnerability factors, include infections like UTIs, or pneumonia, dehydration, and polypharmacy.

And rescranning devices.

Yes.

The text is very firm on this.

Tying someone down is a great way to cause or worsen delirium.

It increases fear and agitation.

The assessment tool here is the CAM Confusion Assessment Method.

It looks for that acute, onset, and fluctuating course.

So if it's delirium, we don't treat the brain primarily.

We fix the underlying cause.

Exactly.

Antibiotics for the UTI, fluids for dehydration, and nursing interventions are huge here.

Reorient them.

Mr.

Smith, you are in the hospital.

It is Tuesday.

Give them their glasses and hearing aids so the world isn't scary.

Drugs like antipsychotics are a last resort, only for safety, because they can actually mask the symptoms we are trying to monitor.

Now the third D, dementia.

This is the syndrome.

It's chronic,

progressive, and the big one is Alzheimer's disease, AD.

AD accounts for 60 to 80 % of cases.

Pathologically, we are talking about beta amyloid plaques, clumps of protein between neurons, and tau tangles, twisted fibers inside neurons.

These destroy the transport system of the cell, leading to neuron death and hippocampal atrophy.

Let's look at the pharmacology here, because I feel like Aristept, Don Pezel, is on every single med list I see in clinicals.

We know it's for Alzheimer's, but what is it actually doing at the synaptic level?

To understand Aristept, we have to go back to that neurotransmitter we mentioned earlier, acetylcholine.

In the brain, acetylcholine is critical for memory and learning.

It's the messenger.

In Alzheimer's, the neurons that produce this messenger are dying off, so you have a supply shortage.

Okay, low supply.

So does Aristept make more acetylcholine?

No, and that's a common misconception.

We can't easily force the brain to make more.

Instead, Aristept works on the cleanup crew.

The cleanup crew.

Right.

Normally, after acetylcholine delivers its message, an enzyme called acetylcholinesterase comes along and breaks it down to clear the synapse.

It's like a janitor sweeping up the hallway.

Aristept is a cholinesterase inhibitor.

It handcuffs the janitor.

I see.

So if you stop the janitor from sweeping up the acetylcholine, the little bit of acetylcholine you do have hangs around longer.

It stays in the synapse and has a better chance of hitting a receptor and sending a signal.

It's making the most of a dwindling supply.

That is a great way to visualize it.

Handcuffing the janitor.

Yeah.

But that only works for a while, right?

Right, because eventually there isn't enough acetylcholine being made for it to matter.

That's why these drugs are most effective in mild to moderate stages.

But then we have the second class of drugs, mementine or nemenda, and this works on a totally different system.

Glutamate?

Glutamate is excitatory, right?

It revs things up.

Usually, yes.

But in Alzheimer's, you get a chronic leak of glutamate.

It's like a dripping faucet.

This constant dripping overstimulates the neurons until they burn out and die.

It's called

excitotoxicity.

So if Aristept is boosting the signal, memenda is shielding the noise.

Exactly.

Memenda blocks the receptors just enough to stop that background static, the pathological dripping, but still allows the important signals through.

It protects the neuron from burning out.

That's why you often see them prescribed together.

One boosts the signal.

The other clears the static.

Okay, that makes sense.

Now, not all dementia is Alzheimer's.

What about vascular dementia?

How do we spot that versus Alzheimer's?

Vascular dementia, or VAD, comes from blood flow issues,

little strokes or brain attacks.

The progression is the key differentiator.

AD is a smooth slide down, a gradual, consistent decline.

VAD is stepwise.

You have an event, you drop, you plateau for a while, then another event, another drop.

And the risk factors are basically the same as heart disease.

Exactly.

Hypertension, diabetes, smoking.

If you have bad vessels in your heart, you likely have bad vessels in your brain.

Then there's Lewy body dementia.

This one sounds terrifying because of the hallucinations.

It is challenging.

It has of both AD and Parkinson's.

They have visual hallucinations, often very vivid, seeing little people or animals, and they have the shuffling gait of Parkinson's.

But here is the crucial nursing warning.

They are extremely sensitive to antipsychotic medications.

Why is that?

Because of the dopamine issue.

If you give a patient with Lewy body dementia a standard dose of Haldol, which blocks dopamine, you can cause a severe, life -threatening reaction.

It can cause total rigidity.

Nurses need to know.

If you see hallucinations A and D, a shuffle, be very, very careful with antipsychotics.

Good to know.

And frontotemporal dementia.

Picks disease.

Yeah.

This affects the frontal lobes first.

So memory might be okay initially, but their personality changes.

They lose their filter.

They might become aggressive or sexually inappropriate or lose language skills, aphasia.

It's tragic because it often hits younger in the fifties.

Before we leave dementia, is there any good news?

Are reversible dementias?

There are a few, which is why we assess.

The text highlights normal pressure hydrocephalus and pH.

It's a buildup of spinal fluid.

It has a classic triad of symptoms, gait disturbance, incontinence, and cognitive dysfunction.

Is there a mnemonic for that?

Wet, wobbly, and wacky.

Wet for incontinence, wobbly for the gait.

They walk like their feet are magnets stuck to the floor and wacky for the confusion.

If you identify this and shunt the fluid, they can get significantly better.

Wet, wobbly, and wacky.

I'll remember that.

Is.

Okay.

Section four.

We have a patient with dementia.

They are acting out.

What is this?

So what for the nurse?

How do we manage the environment?

The golden rule is that the behavior is a form of communication.

They aren't trying to be difficult.

They're trying to tell you something, but their brain can't form the words.

Let's look at wandering.

Why do they do it?

Boredom.

Or they're looking for the bathroom.

Or they think they need to go to work.

The text suggests interventions like safe paths, let them wander safely, or camouflage the exits.

How do you camouflage a door?

You use their visual deficits to your advantage.

Put a poster over the door handle so it looks like a bookshelf.

Or paint the doorknob the same color as the door.

Because of the agnosia, loss of recognition, they physically cannot distinguish the exit.

It keeps them safe without restraining them.

And sundowning.

That confusion that hits at 4pm.

Very common.

It's linked to the disruption of circadian rhythms and sensory overload.

Interventions.

Light therapy.

Keep the lights bright in the day to reset the clock.

Reduce noise and clutter in the evening.

Don't plan complex tasks for 5pm when their battery is empty.

Paranoia is another tough one.

You stole my purse.

Never argue.

Logic doesn't work.

If you say, I didn't steal it, they won't believe you.

Instead,

acknowledge the feeling and use distraction.

I haven't seen it, but let's look for it together.

Often they just misplaced it because of the memory loss.

Also, check if they can see and hear.

If they can't hear what you're whispering to another nurse, they might assume you're plotting against them.

Section 5 deals with specific neurologic conditions.

Let's talk Parkinson's disease, PD.

We mentioned the hardware earlier.

What is the wiring fault in PD?

It's a neurotransmitter imbalance in the basal ganglia.

You have a seesaw between dopamine and tilicoline.

Dopamine inhibits movement, keeps it smooth.

Acetylcholine excites it.

In PD, the dopamine producing cells die.

So the seesaw tips.

Right.

Without dopamine to act as the break, the acetylcholine runs wild, causing rigidity and tremors.

The text uses the T -R -A -P acronym to describe the symptoms.

Walk us through G -A -P.

T for tremor.

Specifically,

a resting tremor, often called pill rolling with the thumb and finger.

R for rigidity.

The muscles are stiff.

You feel cogwheel rigidity when you try to move their arm.

A for akinesia or bradykinesia slow movement.

They have masked face, no expression.

P for postural instability.

They fall over easily.

What are the nursing priorities here?

Falls are number one.

They have a fascinating gait.

They take little shuffling steps, lean forward, and pick up speed like a runaway train and can't stop.

They also freeze in doorways.

You have to teach them to march to consciously lift their knees.

Also, swallowing dysphagia is a huge risk.

They aspirate easily.

And self -care buttons and zippers become impossible, so Velcro is your friend.

And meds.

Levodoparbidopa.

It provides the dopamine they are missing.

Timing is critical.

If you are 30 minutes late with their meds, they might freeze and not be able to move.

It is not a medication you can give whenever.

Let's switch two -stroke CVA.

Two types.

Ischemic and hemorrhagic.

Ischemic is a clot -blocking blood flow, prombotic or embolic.

Hemorrhagic is a bleed, burst vessel.

Ischemic is way more common.

And the phrase, time is brain.

Vital.

For an ischemic stroke, we have a clot -buster drug called RTPA.

But there is a strict window, usually three hours from symptom onset.

If you wait too long, the tissue is dead, and the drug might just cause bleeding into the dead tissue.

So, rapid assessment is key.

Why can't everyone get the clot -buster?

The exclusion criteria are strict.

If they have had recent surgery, a history of bleeding, or if their blood pressure is too high, you can't give it.

You'd cause a massive hemorrhage.

Nursing care for strokes seems heavy on the rehab side.

It is.

In the acute phase, you position them with the head until lower intracranial pressure.

But then it's about function.

Dysphagia screening before you feed them anything.

You don't want them to aspirate pneumonia on top of a stroke.

What about the vision issue?

Hormonymous hemianopia?

That's a mouthful.

It means they lose the same half of the visual field in both eyes.

So if they have a right -sided stroke, they might not see anything on the left side of space.

So they eat half their dinner and stop.

Exactly.

They literally ignore the left side of the plate.

The nurse has to teach them to scan the room, physically turn their head to bring the missing side into view.

It's a learned behavior.

Section 6.

We are wrapping up with pharmacology and mental health.

We've touched on meds, but there are some general rules for geriatrics.

The mantra is start low, go slow.

Older livers and kidneys don't clear drugs as fast.

The half -life of a drug might be doubled.

A formal dose for a 40 -year -old could be toxic for an 80 -year -old.

Specifically, psychotropic meds.

Anti -psychotics.

We keep warning about these.

They are high risk.

They can cause EPS extra pyramidal symptoms.

This looks like Parkinson's shaking stiffness or tardive dyskinesia.

Those repetitive involuntary movements of the mouth and tongue like chewing or lip smacking.

And that can be permanent, right?

Yes.

Even after you stop the drug, that's why we are so cautious.

Also, mention neuroleptic malignant syndrome.

NMS.

Rare but fatal.

High fever, muscle rigidity.

If a patient on anti -psychotics spikes a temp, you need to act fast.

What about

benzodiazepines?

Valium?

Adivine?

The text is pretty firm.

Avoid if possible.

They increase fall risk, cause confusion, and can actually make agitation worse.

A paradoxical reaction.

You give it to calm them down and they get wilder.

Finally, mental health and aging.

We talked about depression, but what about anxiety?

Anxiety is common, but often presents as somatic complaints again.

Or OCD -like rituals.

Older adults might check the door locks 50 times because they feel unsafe.

And somatiform disorders, where they have physical symptoms with no medical cause.

How does a nurse handle that?

It's all in your head.

Never say that.

The pain is real to them, even if the MRI is clean.

You need a non -judgmental approach.

Acknowledge the discomfort, but avoid reinforcing the sick roll.

Focus on function.

I know your back hurts, but let's try to walk to the window.

Wow.

We have unpacked a massive amount of information.

From the shrinking neurons and the janitor enzymes to the wet, wobbly, and wacky gait of NPH.

It is a lot, but if we synthesize it, the core theme of Chapter 27 is this.

Aging brings changes, yes.

The hardware slows down,

but disease dementia, delirium, depression is not inevitable.

It is not normal.

The nurse's role.

The nurse transforms.

You aren't just a caregiver.

You are a detective using those assessment tools to find the baseline and spot the delirium before it spirals.

And you are an architect modifying the environment, changing the lights, hiding the doors, building a world where the patient can still function safely despite their deficits.

I love that.

Detective and architect.

Before we go, I want to leave our listeners with a provocative thought from the text.

It mentions something called benign suicide or passive suicide.

Yes.

This is a heavy concept to end on, but vile.

It's the idea that some older adults silently give up.

They stop eating, or they forget their heart meds, or they just lose the will to keep the machine running.

It's not an active overdose.

It's a quiet withdrawal.

It challenges us to look beyond the chart, doesn't it?

To see the person and their will to live.

Absolutely.

You have to read the spirit as well as the synapse.

Well, on that note, we want to thank you for joining us on this deep dive into gerontologic nursing.

Good luck with your studies.

And remember, start low, go slow, and keep scanning the room.

Take care, everyone.

This has been the Last Minute Lecture Team, signing off.