Dementia sign seen in the shower could predict condition years before diagnosis

Some signs of dementia are easy to miss. Beyond some of the well-known symptoms of dementia such as memory loss, behavioural changes, and difficulties in communication, other less obvious signs can go by unnoticed.

And according to experts, other subtle signs could present themselves in the most unexpected places. One of these is the bathroom.

Neurologist Dr Meredith Bock recently pointed out that failing to catch the distinct smell of your shampoo or soap during a shower might signal underlying cognitive issues. Anosmia, the medical term for losing one's sense of smell, has strong correlations with dementia and could predict conditions like Alzheimer’s disease, Lewy Body dementia, and Parkinson’s.

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This sensory loss could precede an official dementia diagnosis by years. Of course, though, anosmia isn't a definitive sign of dementia - common ailments such as colds, flu, sinus infections, allergies, and even COVID-19 are frequently to blame.

But if it coincides with additional dementia-associated symptoms, it may be indicative of something more serious. Speaking to Parade, Dr Bock, who serves as the chief medical officer at Remo Health, said: "The process of neurodegeneration that causes dementia can also affect sensation and sensory processing related to smell, making it harder for them to recognize familiar scents like their favourite shampoo or body wash."

It is thought this occurs due to the fact the area of the brain that governs smell can become damaged by dementia. One study, published in the Alzheimer’s and Dementia journal in 2023, found that a loss of smell was linked to an increased risk of dementia.

During the comprehensive study, researchers followed over 2,400 individuals for almost eight years to observe the correlation between their sense of smell and dementia development. Findings disclosed that participants with a total absence of smell had an almost tripled risk of dementia, while those with hyposmia, a decreased ability to detect odours, faced an increased risk of 1.76 to 1.85 times.

The term "severe olfactory dysfunction" was used to describe major reductions in smell capability, which also spelt a grim prediction for brain health – with very poor smell function corresponding to a 2.56-fold increase in dementia risk. Furthermore, a separate University of Chicago medicine department-led investigation noted that a sharp decline in smell during a period of otherwise normal cognitive function could signal several hallmarks of Alzheimer’s disease.

Importantly, this insight might allow for pinpointing individuals in middle age who are unsuspectingly on the path to dementia. Neurologist and medical director at Sentara RMH Medical Centre, Dr Fouzia Siddiqui also spoke to Parade, sharing that "an increased risk of cognitive decline and Alzheimer’s disease dementia has been identified in subjects with olfactory dysfunction. Odour identification has been identified as a useful screening tool that predicts conversion from mild cognitive impairment to Alzheimer’s disease dementia."

In cases where someone notices this symptom, Dr Bock recommended checking in with a GP. A doctor can administer cognitive tests to determine if a decline in neurological function might be impacting the sense of smell.

Dr. Bock also mentioned: "Unfortunately, if the loss of smell and taste is due to a neurodegenerative disorder, such as Alzheimer’s disease or Parkinson’s disease, it does not come back."

Amongst the common indicators of dementia listed by the NHS are memory loss, trouble concentrating, difficulty with daily tasks, problems with conversation comprehension or finding suitable words, disorientation in time and place, and shifts in mood. Anyone experiencing these signs should consult their GP.