It's a sad fact that as we get older, a lot of cognitive impairment can come along for the ride. Alzheimer's Disease, senile dementia, and more. There are many issues that can strike in old age, but it's usually easier for writers to just make old people forgetful. It should be noted that not everything going on inside the brain is a disease or a syndrome; sometimes the machinery just wears out, and sometimes people are just absentminded. And sometimes, they're on medications (or medications that interact with other medications they're taking) that make them loopy.
You can usually expect this to be played for pathos, as Grandma or Grandpa rages against the loss of their faculties and their family has to watch the person they love die by inches (not for nothing is Alzheimer's called "The Long Goodbye").
However, sometimes it's given a more immediate urgency, as when the person has forgotten some piece of information vital to saving the world or doesn't remember that he's an agèd, ass-kicking hero with at least one more good fight in him. In this case, you can probably expect a variant of Easy Amnesia, if only temporarily.
Sometimes though, this trope can be downplayed, as Granny's memory is just shown to be faded, but has no real bearing on the plot, and can usually be used for a cheap laugh. Sometimes seniors take advantage of others' expectations and feign this as a form of Obfuscating Stupidity. Compare Grandparental Obliviousness and The Fog of Ages.
Please limit real-life examples to notable cases of age-related memory loss, and keep it civil.
- It was implied that Aunt May was a little senile in the early days of Spider-Man. Characterization Marches On and this is no longer the case (now she's sometimes more aware than Peter himself).
- In Brightest Day, the newly-resurrected Martian Manhunter tracks down Melissa Erdel, the daughter of the scientist who brought him to Earth, in hopes of learning more about the late Dr. Erdel's research. Unfortunately for him, Melissa is now an old woman whose memory is failing her, no thanks to a chunk of machinery stuck in her brain from the accident that brought J'onn to Earth, but she does remember enough to recall that J'onn wasn't the only Martian that she and her father managed to summon. At the conclusion of the story, J'onn is able to use his intangibility to remove the shrapnel from her head, helping clear up some of her memory issues.
- X-Factor (2006): The elderly Doctor Doom of Bishop's future is suffering from severe dementia. He's well aware of his condition, admitting he has good days and bad days, and even on his good days he's not entirely lucid (addressing Cyclops as "Mr. Clops", for example). Of course, his skill with technology is just as good as ever, even on his bad days.
- The Bolt Chronicles: In "The Spaceship," Rhino has bouts of advanced-age cognitive impairment, at times suffering from paranoia, anger, and delusions.
- Mama Coco in Coco is a sympathetically portrayed example. She very obviously has some kind of dementia, since she's very old (she's Miguel's great-grandmother), struggles to tell her family members apart, and is mired in the memories of her Disappeared Dad, who she thinks is coming back despite him being long dead. This is actually a plot point, since she is the only one who actually still remembers Héctor, but her memories of him are slipping, meaning that it's only a matter of time before he suffers his Final Death from being forgotten. However, in the end, once Miguel plays Remember Me for her, she remembers everything about Héctor and is for a while more lucid than she has been in the entire film.
- Little Angels: The Brightest Christmas: Daniel seeks shelter in a cabin owned by an old man named Zeke Eaterman, who initially took Daniel for a salesman and his dog for a horse, and rambled on while Daniel tried to set him straight. Then, when Daniel asks for the phone, he excitedly points it out to him, only to then mention that the phone isn't plugged into anything.
- Angelo Ledda in The Alzheimer's Case, who is trying to do One Last Job while his memory is starting to fade.
- The film Still Alice is about a middle aged woman who suffers the onset of Alzheimer's.
- Rise of the Planet of the Apes: The development of the virus that would lead to intelligent apes and the pandemic that would dethrone humanity was originally designed to treat Alzheimers's.
- Mars Attacks!. Richie's grandmother calls both of her grandsons (Richie and Billy Glen) "Thomas".
- Friends with Benefits, the movie is pretty lighthearted, if not a bit raunchy, up until Dylan's father is introduced, who is clearly suffering from memory loss. The Death Cab for Cutie song "Follow You Into the Dark" is played during this scene, which doesn't help matters. Another scene has his father panic while out at dinner, when he wonders why his ex-wife isn't coming to dinner with him. At the end of the film, one of his memory lapses prompts him to advise Dylan to patch things up with Jamie, as the former cites an example of a woman he himself let go of.
- Peter Jackson's The Lord of the Rings: The Two Towers portrays King Theoden this way, sort of. He may be possessed by Saruman rather than just corrupted by Wormtongue's influence, but everyone assumes it's old age robbing him of vitality (to say nothing of grief caused by his only son and heir being killed). Particularly apparent when Gandalf removes the corruption/possession and all of a sudden he looks twenty years younger.
- One of the elderly Lost Boys in Hook has "lost his marbles". Literally and figuratively. He finds them by the end of the movie, though.
- In Transformers: Revenge of the Fallen, Jetfire, a decayed ancient robot, is less forgetful and more completely batshit insane. He changes subject back-and-forth at a incomprehensible pace, forgets to mention crucial detail (such as when he teleports everyone to Egypt without a warning), and seems to be overall a bit clueless. His memory in specific, though, is very good: One of his main roles is explaining a lot of ancient history nobody else but him knows.
- The present day story in The Notebook has an elderly Noah reading the titular book to his wife, Allie, whose memory has faded. She has a few moments of lucidity, but they come and go in waves. Her last moment of lucidity results in her and Noah peacefully dying in their sleep.
- Max's mother in The Cobbler, obviously suffers from senile dementia. In one scene Max finds her purse in the microwave.
- Sir Graham in Mortdecai, who seems to be having a bad case of dementia and forgets things every ten seconds or so.
- Professor Xavier in Logan suffers from a degenerative brain disease that's affected his memory, as he doesn't seem to recognize Logan when he's first introduced and rambled about random things, and has also affected his control over his telepathy as when he has a seizure, he can freeze hundreds of people if they're in range to the point harming them and possibly killing them, as it's implied this is how the X-Men died.
- The Dresser: Played very tragically with Sir, the leading man of a troupe of Shakespearean actors. He is unable to remember lines or even remember what play they're doing. He also has wild emotional outbursts in public, as well as occasionally slipping into near-catatonia.
- Aunt Emily in What a Carve Up!. She says she is knitting balaclavas for the boys in the trenches. When Syd says she's a bit late for that she responds "Of course not. It only started in 1914". (The film is set in 1961). She also thinks George Bernard Shaw is alive and offers to introduce Ernie to him, and cannot keep track of who is alive and who is dead.
- Discussed in Waiting... when Monty meets an elderly man who claims that it's great at his age to be able to wander around in your underwear and flip off children because everyone just assumes he's senile, but then laments that he doesn't always realize he's doing it until someone slaps him which means he really is becoming senile. Later, Monty excitedly remarks that he's the coolest old guy he's ever met.
- The Spirit of '76: Dr. Von Mobil, the one man old enough to remember what life was like before the magnetic storm that degaussed all recorded history, is barely capable of stringing a sentence together and confuses the Preamble to the Constitution with the Miranda Rights.
- in On Golden Pond, Norman has trouble remembering people in old photographs and at one point gets lost in the vacation spot he's been coming to stay in every summer for years, and it terrifies him.
- The movie Away From Her is about a man who is forced to check his wife into a nursing home due to her rapidly advancing dementia, and he has to watch while she forgets him completely and strikes up a romance with another resident.
- Knives Out introduces Wanetta "Great Nana" Thrombey as one of these, being the oldest Thrombey (nobody knows her age, but her son is 85) and having lost a mental acuity, rarely ever moving or speaking. However, she's also the least dysfunctional member of her family aside from her late son, and she ends up providing a vital clue for solving his murder.
- Remember: Zev is 89 and suffering from severe dementia, to the point he often forgets what he's doing or that his wife recently died. Not only that, but he forgot his own Nazi past.
- In Relative Fear, Earl addresses his daughter Linda as "Katie," the name of his dead wife.
- A doctor gets an elderly patient's results back and gives him the bad news: he has cancer and Alzheimer's. The patient nods stoically and say it could be worse: he could have had Alzheimer's too.
- Inverted in one version of the scary story where a babysitter notices an Uncanny Valley statue who turns out to be an escaped murderer. The babysitter notices the statue, calls the family, and the grandfather who answers tells her they don't have a statue. The babysitter is about to take the kids and run when the father calls back: they did order a statue, but thanks to her they know the grandfather has Alzheimer's.
- Brothers Keepers: Brother Zebuluon, one of the two oldest monks, isn't quite all there, although he does remember some useful tidbits now and then.
- A Brother's Price: The Porters had some mothers who were rather scatterbrained, and described as "ancient". They died in an explosion, caused by a bomb the Porter family had planted there. The younger ones wanted to get rid of the scatterbrained seniors who they feared would spill their murderous secrets.
- The Knight Camaris, in Tad Williams' Memory, Sorrow and Thorn trilogy needs to be awakened from a long senescence.
- Famed magical historian Bathilda Bagshot from Harry Potter is one of the oldest characters in a series where Wizards Live Longer. Shes known Dumbledore since he was a kid and he is in his 110s throughout the series. Shes also Grindelwalds great aunt and hes a year or two younger than Dumbledore. All this suffice to say, shes very old and could be in the 150 ballpark. However by the time of the last book shes, as someone else put it, nuttier than squirrel poo. Rita skeeter also calls her Batty Bagshot. Although Voldemort had killed her and Nagini was inhabiting her body by the time Harry meets her so its not clear if shed actually lost her facilities.
- El Patron in House of the Scorpion suffers from this towards the end of his life. He harvests brain implants from fetal clones of himself to regain his lucidity however.
- The elderly and absent-minded Professor Regius Chronotis ('Reg') from Dirk Gently's Holistic Detective Agency describes his memory as being "like the Queen Alexandria butterfly, in that it is colorful, flits prettily here and there, and is now, sadly, almost completely extinct."
- A Song of Ice and Fire:
- Archmaester Valgrave, the ravenology teacher at the Citadel of Oldtown, is known for being particularly senile, and a younger aspirant usually takes his place on the Conclave of Archmaesters. Another maester, Aemon, was, on the contrary, unusually lucid for his (very) advanced age, but shortly before his death he started succumbing to scatterbrainedness. And this was Played for Drama (unlike with Valgrave above) and led to a particular Tear Jerker.
- This was also the case with Aemon's great-great-great-great-great (-great, depending on how you trace the line of descent) grandfather Jaehaerys I. For both of them, it was probably due to their impending deaths wracking their minds as well as their bodies; as senility doesn't usually manifest itself so quickly and the 69 year-old Jaehaerys was a little young to be going senile.
- Likewise, Jaehaery's wife Alicent starts to mentally unravel during the last year of her life.
- One of Mr. Wednesday's cons in American Gods was pretending to be a helpless old man completely befuddled by modern gadgetry.
Shadow: By my count, that young lady just paid you twice for the privilege of having you at her gas station.
- Warrior Cats:
- Graypool has something like dementia: she gets confused frequently, getting the past and present mixed up. She tragically meets her death this way: she wanders off alone, thinking she's going to a Gathering, confuses Tigerstar for the long-dead father of her adopted kits, Oakheart, and reveals the secret that the kits are from ThunderClan. Tigerstar gets impatient with her, and, flustered, she steps backward, loses her balance, and falls down a slope, hitting her head.
- Played for Drama with Bluestar. During her last life she turned into this mainly due to Sanity Slippage caused by her deputy Tigerclaw betraying her. Bluestar couldn't focus and would get the past mixed up with the present, amongst other issues. Word of God is that she suffered from dementia. Bluestar wasn't even that old when she started becoming scatterbrained; she wasn't even seven years old.
- Holden's unseen grandmother in The Catcher in the Rye is senile. She sends him birthday money multiple times a year.
- Miss Trixie in A Confederacy of Dunces is blatantly senile and has become incompetent at her job, desperately wanting to retire. Ironically, her bosss wife forces him to keep her around under the belief that her job is all she has left.
- In Diary of a Wimpy Kid, when Great-Granny Meemaw was alive, she was in charge of putting the prizes in the plastic eggs for the family Easter egg hunt every year. When she got really old, she started putting strange things in the eggs like green beans, tissues, and her valuable diamond ring.
- Language Arts: Sister Georgia, one of the residents of Cody's nursing home, thinks she's still working as a teacher at a Catholic school for disabled kids. She doesn't understand where all the children have gone.
- The 7 Yüz episode "Refakatçiler" shows how Serhat's increasingly forgetful behavior, in addition to his physical ailments, lead to a frustrating loss of independence. Vildan pointedly reminds him more than once when he leaves the burner running, to his disdain.
- Madam Secretary: After Air Force One goes missing with the President and Speaker of the House on board, and the Vice President is out sick, an elderly Senator is called in to swear in as president. However, a comment he makes reveals that he believes Ronald Reagan is still president, forcing Elizabeth to become president.
- In the third season of The Story of Tracy Beaker, we are introduced to Jackie, who has come into care after her grandfather, who was her main carer, develops Alzheimer's and can no longer look after her. At first, Jackie has a really hard time accepting this as she loves him dearly and doesn't want to lose him as he's her only living relative until he passes away in Season Four, but gradually comes to terms when she sees how badly affected he is.
- An episode of The Dumping Ground has Gina, one of the care workers, bring her elderly mother, Hattie, to Elm Tree House after Hattie's carer is taken ill. As the episode progresses, it becomes evident that Hattie requires care because she has Alzheimer's. For instance, she mistakes Faith (one of the young people) for Gina, fails to recognise Tee (another of the young people), who ends up having to keep re-introducing herself, and forgets repeatedly that she has been brought to Elm Tree House.
- House of Cards (US):
- Donald Blythe's wife suffers from Alzheimer's disease. Frank uses this to his advantage to aid getting him to support a budget bill.
- In Season 3, a Supreme Court Justice comes to the President and quietly admits to being diagnosed with Alzheimer's, requesting retirement. He's encouraged to remain on the bench because it would be politically inconvenient. He has an episode of losing his train of thought during a public legal proceeding, and forgets the name of a long-time colleague. Later, because the wind has shifted, the Pres. needs him off the court but he refuses to quit, confounding the Commander in Chief's schemes.
- Jimmy Cavanaugh in Orange Is the New Black. She ends up breaking her arm when she mistakes the chapel altar for a diving board, and is later given compassionate release. Considering the state of the social net in the modern day United States plus the fact she is a convict, it's pretty much a death sentence for her.
- In Law & Order, Det. Ed Green's dad is mentioned as having Alzheimer's.
- Star Trek: The Original Series episode "The Deadly Years". As a result of exposure to radiation from a comet Captain Kirk and several other Enterprise officers undergo Rapid Aging. Captain Kirk is shown forgetting things several times, including several orders he had given, that he had signed a fuel consumption report and that the Romulans had broken Code 2.
- In the premiere of NCIS: New Orleans a former NCIS agent is murdered causing Pride and Gibbs to reinvestigate a case all of them worked on together decades ago. Only one other member of that team is still alive so they go to visit him to see if he can give them any insight into what really happened back then. However, the guy suffers from Alzheimer's and while he remembers Pride and Gibbs, he quickly forgets why they are visiting and cannot provide them with any useful information.
- The soap opera farce Soap features the character of Major Gatling, father of the main characters. He is a veteren not only suffering from some form of senile dementia, but with a touch of PTSD. He believes himself to still be fighting WWII (occasionally with live ammo). It's all Played for Laughs.
- In Unforgettable Carrie has a Photographic Memory. The Ironic Twist is that her mother is in a nursing home and due to Alzheimer's doesn't remember Carrie.
- Nash Bridges has a rare instance of this afflicting a regular character: Nash's father Nick (James Gammon).
- Cougar Town plays this distinctly not for laughs. Late in season four, Jules takes her father to the doctor for what she thinks is an overdue physical only to discover he'd already gone the previous month and forgot about it. It turns out he's stricken with Alzheimer's.
- Geriatric issues show up several times on Scrubs, naturally. There's Johnny, the tackling Alzheimer's patient, Pickles (an old man who only says "Pickles!"), and more.
- An Emmy Bait episode of The West Wing sent C.J. Cregg home to visit with her father, whose struggling with Alzheimer's. Notable in that it depicts and describes the condition accurately. Also, it's heartbreaking.
- One season saw a running sub-plot of a Justice on the Supreme Court writing opinions in verse. Eventually it becomes clear that he's having episodes where his faculties are failing, but "On my good days, I'm better than anyone you could hope to get on the bench", and refuses to step down.
- Shows up on two different occasions on Lost Girl
- A second-season episode is built around the purchase of a weapon of mass destruction, however the weapon is a geriatric grandma... her trigger is taking away her portable TV, then telling her your enemies are responsible.
- A third-season episode sends Bo back to her childhood home for some Epiphany Therapy with her sex-hating mother, only for her to find a sweet old widow who barely remembers that Bo even left, let alone why.
- An episode of Psych has Shawn investigating two related crimes committed some thirty years apart, motivated to help his father's former partner, now rather lost to Alzheimer's.
- An early episode of Eureka involves a long-forgotten relic of the Cold War, and Carter has to hunt down the guy who invented it. Then he has to find a way to get the guy's noodle back in order.
- Played very darkly (naturally), in the Torchwood episode "Out of Time". A biplane containing passengers from the 1950s gets displaced in time and ends up in the present. One passenger wants to track down his son, who would now be an elderly man. Turns out he's in a nursing home with Alzheimer's and while he can remember random bits of his past, he isn't nearly lucid enough to know what any of his memories mean and doesn't recognize his own father. Seeing his son in that state is what convinces him there's nothing left for him, and he is Driven to Suicide.
- One episode of Community had Pierce join a gang of seniors who kept being jerks to people, relying on their age to get away with it. One of their gags was pretending to be lost and senile so that random cops would take pity on them. This was subverted when one of them actually did have a serious lapse... while driving a car. Ultimately not played for laughs.
- Played for laughs with Pierce himself, who can't seem to remember anything past a week. At one point the group exploits his memory problems to convince him they didn't forgot his birthday. The last one didn't work out as well as they thought, though.
- In the later seasons of Stargate SG-1, it's discovered that the Goa'uld System Lord Yu is beginning to go senile, though his First Prime is doing his best to hide this fact and run the empire in his place. This is troubling to the heroes, because while Yu is just as evil and megalomaniacal as any other System Lord, he was at least rational and pragmatic compared to the outright psychosis of his fellows, and thus could be counted on for an Enemy Mine situation when it was necessary.
- Absolutely, positively not Played for Laughs in Black Mirror "Playtest". The protagonist of the episode, Cooper, lost his father to Alzheimers and succumbing to it himself (or even worse, losing his mother to it) is one of his deepest, most personal fears. The brain-altering horror game he was playtesting uses this against him and it completely shatters his mind, Room 101 style.
- Deus Salve O Rei: Queen Crisélia is going senile by the start of the story and beings suffering very random memory losses (such as forgetting that her daughter died a long time ago) and begins talking to herself. This is why in one of her lucid moments, she tells her grandson Afonso to succeed her when he returns from his expedition.
- Call the Midwife: The elderly Sister Monica Joan is implied to have mild dementia. She's mostly a benign Cloudcuckoolander who's very good at her job in Nonnatus House despite her flights of fancy, but her condition is sometimes Played for Drama, such as when she loses concentration during a phone call with a woman in labour.
- Live Forever As You Are Now with Alan Resnick: "Elderly Woman" Jordan Card claims that drawings of herself are birds and frogs, and talks to her digital clone about nonsense subjects, such as the fact that it's a Monday. Her clone doesn't fair any better, and just rants about how cold the room is.
- Played for laughs (mostly) with Maw-Maw on Raising Hope. She is implied to have some type of dementia, and has occasional moments of lucidity, when she accuses Burt and Virginia of mooching off her. (In actuality, although it may have started out that way, they're actually the ones taking care of her, and in fact when she's removed to a nursing home by the state, she's miserable there because the Chances knew her quirks and were better able to deal with them than the nursing home was.) She relives parts of her life from when she was younger, and has multiple hidden talents, some that show up when she's lucid, others that show up when she's in her delusions. A Running Gag (especially early in the series) was Maw-Maw taking her top off when it was not appropriate to do so.
- Merle of The Adventure Zone: Balance is the oldest member of the group, and can be very scatterbrained. He tends to forget about his magic or items more than the other party members. Lampshaded when Istus gives Merle a magic item that will allow him to send himself 9 seconds into the past in order to fix a mistake.
Magnus: I just wonder how long it'll take him to forget he has that.
Merle: Forget he has what?
Merle: I prostate myself before you—
- He (and Clint) also has a tendency to forget people's names, calling Lucretia "Lucinda", and Istus "Isthmus". He even forgets his own surname. Twice.
- He also will occasionally say one word when he means another.
- In It Makes A Sound, the Other Voice in Deirdre's house, whose outbursts and activities consistently interrupt the broadcast of her amateur radio show, is heavily implied to have some form of dementia, especially judging by her attempt to speak into Deirdre's mic while she's away.
The Other Voice: "Who's there? I'm in the hole. Yes, I'm n-the sixteenth hole. If you can find, wined and dime it...*clapping noises* I am the hole-holy smokes..."
- Harper thinks this of Woods in Call of Duty: Black Ops II during the introductory scene. However, he is proven wrong seconds later, as the latter is still very with it.
- Rosine of Granblue Fantasy is often featured in events and is interacting with other younger characters. Sadly she has some mild dementia due to her age and often forgets Lyria and Vyrn's names. She mistakes Vaseraga for her husband in a Fate Episode due to some very thin similarities (i.e. a large man carrying a large scythe) even though the latter always wears a helmet.
- Old Reece from Grand Theft Auto: San Andreas is implied to be this, as Ryder mentions the former having 'popped his membrane years ago'. Indeed, he will talk to CJ in a manner that suggests he is mentally in the past.
- Michelle Walthers in Deus Ex: Human Revolution is this. Her mind is probably years ago in the past, as she insists to an adult Adam that he is only in his childhood (while thinking that the adult Adam is a food delivery driver). After completing her side-quest, if the player tries to press her for information about Adam's real parents after she discusses the White Helix labs, she will continue to forget the conversation, leaving the player no choice but to leave.
- Deus Ex Machina 2 (which is not related to the above) follows the protagonist's entire lifespan, and depicts his going senile by having the clocks throughout the previous Old Age stage turn into a mess of shattered parts that he floats through, encountering portals leading to low-res versions of several of the previous stages in reverse order as he deteriorates further and further. The final gameplay stage ("Wonder") has him wandering aimlessly through a winding road as a song from the perspective of a child who can't find their parents plays in the background.
- Anju's grandmother appears to have this in The Legend of Zelda: Majora's Mask, as she thinks Link is her deceased son (or the mayor as a child if he's wearing Kafei's mask). However, reading her diary shows that she is quite lucid, and she only fakes it to avoid having to eat Anju's terrible cooking.
- The premise of Ether One is that you are using cutting-edge technology to embark on a Journey to the Center of the Mind of such a person. Through it, you learn some information about the patient's experiences with their failing mental facilities including that the patient could not remember why he was attending a funeral (for what turns out to be the patient's spouse), that the patient once struggled to make a music box work only to be told that it was actually a cushion, that the patient has suffered extremely unpleasant outbursts due to misplacing things and, finally, that the technology does not exist, and that you are the dementia-afflicted patient and that your experience is an internal struggle to sort out your own memories.
- In Persona 4, Hisano's husband was clearly suffering from some sort of dementia, probably Alzheimer's, before his death (even if the game never uses the word) to the point of forgetting who she was. She considered his passing a mercy and is still incredibly broken up by it when you meet her.
- Sensei from Advance Wars 2 and Dual Strike seems to have shades of this, though it's unclear how much of this is down to humility and not wanting to be the centre of attention. He dismisses the idea that he was once a practically unbeatable C.O. in his bygone yearsnote as mere rumours from so long ago that he had almost forgotten.
Sonja: Sensei! You did it! You are victorious!
Sensei: Hm? I am? Oh, that's nice.
- Implied for Gran from Survivor: Fire, who bakes brownies at two in the morning and then doesn't go out of the kitchen when they burn and start a fire.
- The Phoenix Wright: Ace Attorney trilogy has two witnesses that Phoenix has to face with this characterization. Both of them are subversions.:
- In the first game, the caretaker of the boat rental shop Phoenix and Maya investigate is a textbook example. He's so disconnected from reality that he thinks he runs a noodle shop. He believes the two are his grandchildren Keith and Meg and says that they will inherit the noodle shop someday. He's prone to falling asleep and does so several times, even when he was on the stand, and can't even remember his own name. It turns out that he was Obfuscating Insanity. His real name is Yanni Yogi and he was the court bailiff trapped with Miles Edgeworth and his father Gregory in the elevator. He was framed for killing the latter and his lawyer used the Insanity Defense, citing oxygen deficiency being trapped in the elevator, to have him declared innocent even though he really didn't take Gregory's life.
- In Trials and Tribulations, it's Victor Kudo, a Dirty Old Man. The resulting cross-examination makes it look like Kudo's memory has gone bad, due to his testimony not matching up with some of the evidence. This cross-examination also tries to make it out that he was only looking at the waitress' outfit, meaning he couldn't properly identify the defendant. As it turns out, Kudo's memory is just fine despite his age. The inconsistencies were the result of Kudo witnessing not the actual murder, but a reenactment that was done to frame Wright's client. And the waitress of the reenactment purposefully hid her face from Kudo's view.
- In Don't Starve's character film for Warly, "Taste of Home", he is shown caring for his elderly and disabled mother and jogging her memories by cooking for her the meals she used to cook for him. She relapses as soon as the meal is over, and isn't aware enough to react when he's kidnapped to the Constant on his way to wash the dishes.
- In the good-prevails ending of Myst V: End of Ages, we meet an aging Atrus—who mistakes Watson for a long-dead friend, implying that as of the mid '00s he was in the early stages of Alzheimer's.
- Davan Macintire's father, Fred, was diagnosed with Alzheimer's several years into Something*Positive. He remained lucid for quite a while, using it as an excuse to play pranks on his kids, but steadily deteriorated over time and died in 2020.
- Stand Still, Stay Silent: In a character's backstory, the warning signs of someone being Brainwashed and Crazy were mistaken for the early stage of dementia due to the person being of a fairly advanced age.
- Poison Ivy Gulch: Parodied here when the mayor meets an old man protesting senility.
- FreedomToons: Joe Biden will invariably be portrayed as a senile old man who barely comprehends what's going on around him.
- In The Tourettes Guy, Danny's ex-wife Shirlena has a grandpa with Alzheimer's who began taking his clothes off in a K-Mart one day. Danny found this story more hilarious than heartbreaking.
- The bots of the Jolly Roger Telephone Company are designed to waste the time of telemarketers and other annoying callers. One of them, Whitey Whitebeard is designed to exemplify this trope and thus makes a great choice for those looking to scam the elderly. He rambles about the bad weather, talks about how hard it is for him to get up to go answer the door, and generally seems like he's not quite all there. Later iterations of him even have a custom routine in which if the AI detects a medical scam, he will start talking about his back pain and ask if the scammer has medication which can treat that.
- Plonqmas: Plonqs mother is revealed to be suffering from dementia in A Plonqmas Tale — 2018. He is urged to call her for the holidays, and does so at storys end.
- The Proud Family: Suga Mama dates another senior citizen named Clarence. While her family assumes he is trying to take advantage of her, it is later revealed at the end of the episode that his memory is addled, and had been missing from home for awhile. The wedding they planned to have is called off, leaving Suga Mama heartbroken.
- Goldie Delicious from My Little Pony: Friendship Is Magic is a distant relative of the Apples; she is portrayed as an elderly woman that lives with dozens of cats in a dusty house filled with junk. It's never stated but she seems to fit perfectly within the symptoms of Diogenes syndrome.
- Granny Smith was at least a little senile in the early seasons, but she's mostly lucid nowadays due to Characterization Marches On.
- Hey Arnold! Arnold's Grandma is pretty much insane. This trope is played for laughs though, as her shenanigans are used for comedic effect. The only time she is shown to be normal is in flashbacks and in an episode with a rough heat wave droves everyone else crazy while driving her sane.
- One interpretation of Granddad's tall tales in The Boondocks is that he is suffering from the early stages of dementia.
- Played for Laughs in SpongeBob SquarePants with Mermaid Man, whose memory leaves much to be desired.
- Grandpa Dave is implied to have an early stage of this in the Arthur episode, "Grandpa Dave's Memory Album".
- The South Park episode "Cash for Gold" implies that grandpa Marvin Marsh has Alzheimer's and he explicitly says he does in "Nobody Got Cereal?"
- The Simpsons:
- Abraham "Grandpa" Simpson has a pretty heavily eroded mind. This can range from simple forgetfulness to being completely divorced from reality. He once kept two policemen occupied by claiming to be the Lindbergh baby and wanting his "fly-fly dada". When the police ask if he's trying to stall them, or if he's just senile, he admits it's "a little from Column A, a little from Column B". This is consistently played for laughs.
- Mr. Burns, Homer's elderly employer, dips his toe in and out of this trope. Sometimes he's quite clever and shrewd, but other times he seems unaware that it's not still the 19th Century, and he's never able to remember who Homer is, even after being reminded that "all the recent events of your life have revolved around him in some way." This is also played for laughs.
- Danger Mouse's superior Colonel K became this as this series went on. He can never remember how to end a transmission or gets transmission sign-offs confused.
Colonel K: Over and out? No, 127 to 5, last thing I heard.
- In season 4 of BoJack Horseman, BoJack's mother Beatrice has succumbed to dementia, which BoJack very reluctantly deals with since she wasn't the best mother to him. She confuses him for a maid named Henrietta and tends to get the past and present day mixed up. The episode "Time's Arrow" is a Whole Episode Flashback to her youth as shown through the lens of her deteriorating mind, with disturbing details like background characters' faces being completely blank and the letters on signs glitching and getting mixed up. By season 5, she has died from it.