WWII Carbolic soap apparently helped a man who was socially outcast because he just would not bathe, had developed a fear of water. So a scent museum in England helped get the soap to him, and apparently it helped him recall pleasant memories of bathing in front of the fire.

One institution has (had?) scent memorabilia  available in candy-machine type dispensers. A leather ball glove for memories of going to baseball games etc

This article has such a great title, I had to include it.

This is fascinating.  Scents are indeed tied to memory, in most cases good memories.

There are two parts of the brain--the olfactory bulb and the hippocampus--where neurons can be regenerated.  Both are damaged in Alzheimer's disease.  Interesting essential oils via aromatherapy can be used to treat both the loss of smell and Alzheimer's disease.

https://www.the-scientist.com/notebook/regularly-whiffing-essential-oils-can-retrain-lost-sense-of-smell-32599

https://www.ecu.edu/news/newsstory.cfm?id=947

I found carbolic soap for sale in the UK. Okay not so helpful, I will keep looking

For Christine Kelly, an American expat living in England, smell training restored a perceptual experience she had lost completely after a viral infection four years ear­lier. Her anosmia led to depression, and during this low point Kelly met a clinician who introduced her to smell training with essential oils. On her train ride home from that initial visit, Kelly decided that if she were to do this, she would observe herself along the way. “In that respect I became a student of anosmia, rather than a victim,” she says.

She kept careful track of her training—noting how well she could pick up a scent, distinguish it from others, and smell it the same way she had before the infection (a common problem among those who suffer from a loss of the sense of smell is parosmia—scent distortion).

After a few months of training, odors began to come into focus for Kelly. At first, they were terrible. “Everything had an unearthly, disgusting smell that would vacillate between burning Teflon frying pans [and] spoiling ham sandwiches that had been left inside a camper van in the rain for three months,” she recalls. Then, with continued training, Kelly was able to get a fix on lemon. More and more smells followed.

Since its likely that other people are just as link wary as I am, I am pasting some of the contents from Lane's links below for convenience.  Here are the scents used and their effect.

To stimulate appetite, a scent mixture of grapefruit and clove is sprayed on patients’ bibs before mealtime.

A scent mixture of grapefruit and frankincense is used to help curb the so-called Sundown symptoms, such as anger and sadness, that often occur during the early evenings.

A third scent, a mix of rosemary and orange, is offered to caregivers and staff to help ease stress and stimulate creativity.

 “These scents release seratonin and endorphins and can decrease depression and pain in the brain,” she said. “If people are more alert, it decreases falls. And because people are feeling better, they sleep better, which makes them sturdier on their feet during the day.”

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“When people smell things, they are linked immediately and unconsciously to the past,” she said. “When you take a vitamin or an essential oil, it is made up of the same molecules as the body. It uses what it needs and the rest is eliminated.”

The study enables Loy to look at how appetite and moods are affected by the scents. To stimulate appetite, a scent mixture of grapefruit and clove is sprayed on patients’ bibs before mealtime. A scent mixture of grapefruit and frankincense is used to help curb the so-called Sundown symptoms, such as anger and sadness, that often occur during the early evenings.

Participants who receive one scent do not receive the other scent. A third scent, a mix of rosemary and orange, is offered to caregivers and staff to help ease stress and stimulate creativity. In the past, Farnell said she has seen dozens of people helped by the aromas and hopes even more will be helped through this study.

“These scents release seratonin and endorphins and can decrease depression and pain in the brain,” she said. “If people are more alert, it decreases falls. And because people are feeling better, they sleep better, which makes them sturdier on their feet during the day.”

Mary Knapp, 90, a resident at Beverly Health Care, is one of the dozens of participants in Loy’s study. Each day she wears on her sweater a heart-shaped patch scented with frankincense and grapefruit. Knapp described the scent as “mellow.”

Knapp’s daughter, Mary Langston, of Greenville, said she has noticed a marked change in the past few weeks in her mother’s attention span and ability to better remember relatives in photographs and scrapbooks.

“It’s been nice. It makes it so much easier to sit down and talk to her. As a child, you can’t imagine your parent’s not being able to remember things. But lately, it’s like she has been reborn,” Langston said. “She doesn’t get upset that she can’t remember things. Her attention span certainly has improved and she enjoys being around people more. Noises aren’t as disturbing for her.”

Beverly Health Care recreational therapist Amy Smith, who directs the study with nine patients at the care facility, said that keeping residents off medications helps them to be more alert and aware of their surroundings, and more willing to engage with others.

I keep thinking that I am following all these posts and then I keep missing some.  Thank you for these posts and all your posts HowDoYouDeal.  

There are two parts of the brain in which neurons can be regenerated: the olfactory bulb and the hippocampus.  These parts of the brain are also damaged in Alzheimer's disease.  Both sense of smell and certain memories can likely be at least partially restored via aromatherapy.  

Years ago, the mother of a nurse involved in the above study was on these boards.  She told me that once the study stopped the residents lost access to aromatherapy and they lost the improvements that they had made.  It made me sad to hear that.

For my mother we used a variety of essential oils via aromatherapy including rosemary, clove, oregano, thyme, bay laurel, and orange.  All except the last are stimulating essential oils (my mother used to say they almost knocked her out).  A few people have told me that the more stimulating essential oils increased agitation in their loved ones.  It is not clear whether the use of more relaxing essential oils such as lavender, orange, lemon balm, and rose would counteract this potentially negative side effect.

The most direct route to the brain is through the nose.  Several of the chemicals in several essential oils act as antioxidants which leads to some growth of neurons in the hippocampus and improvements in certain forms of memory (facial recognition, object recognition, sense of time and place, and overall alertness).

Here is another fascinating approach using the senses (especially the sense of smell) to help treat Alzheimer's disease:

Multi-sensory potential of archives in dementia care

This paper aimed to review the potential for archival items to be used to support therapeutic interventions in dementia care, with a particular focus on olfactory stimuli. Archival research was used to identify objects and to re-create authentic historical product fragrances from Boots UK. Potentially therapeutic material and smells for people living with dementia were identified and olfactory profiles created. These were characterized by strong smells and items featuring well-known brands and distinctive packaging including carbolic soap and Old English Lavender talcum powder. A dataset of items has been created for use in future research studies...

Further investigation of olfaction seems warranted, given the powerful association between smell and memory, the links between olfactory impairment and dementia, and evidence suggesting that smell can have a positive impact in care environments. This study sought to explore the potential for archival research to provide insights into re-creating authentic smells from the past to create olfactory stimuli of therapeutic value for use in dementia care settings, thus providing foundational knowledge to support further study...

A female living with dementia, who was largely mute according to carers, became animated and spoke lucidly when presented with a recognizable fragrance (perfume) which had been re-created using a formulation from the archive and some faux jewellery. Her husband advised that her reaction was remarkable and that she had been a jeweller, perhaps explaining why these items had such an impact. This example underlines the importance of combining olfactory with other stimuli, in this case object handling, creating a multi-sensory as well as personalized experience for someone living with dementia...

Another male living with dementia was restless and agitated, yet he displayed interest and engagement when exploring photographic equipment and shaving products. He became notably calmer as he demonstrated his knowledge of photography, including naming different camera components and techniques, whilst sharing anecdotes about family holidays, grooming routines, and loved ones that he would photograph...

Certain smells and certain objects can connect people with their past.  In addition the chemical processes behind multi-sensory experiences such as aromatherapy, flashing lights, music, et. can improve certain forms of memory in people with Alzheimer's disease.

"Why I Smells Like it's 1903" may provide part of the answer to treating Alzheimer's disease.

This is a link to the beginning of the archives:

http://archives.walgreensbootsalliance.com/

Not sure if more useful resources exist focusing on items that might be helpful to someone with Alzheimer's disease.