Dementia, including Alzheimer’s disease, can indeed cause people to forget the purpose of common objects, a phenomenon linked to the broader decline in recognition memory and cognitive function. This happens because dementia progressively damages specific brain regions responsible for memory, understanding, and the association of objects with their uses.
One of the key ways dementia affects memory is through the breakdown of neural structures that support recognition and meaning. Recent research highlights the role of perineuronal nets—delicate mesh-like structures that surround neurons and stabilize their connections—in maintaining social and object recognition memory. In Alzheimer’s disease, these nets deteriorate, especially in the hippocampus region called CA2, which is crucial for social memory, such as recognizing familiar faces and relationships. When these nets break down, patients lose the ability to recognize loved ones, even though their memory for objects may remain intact for some time[1][2][3][5].
This selective loss of social memory is heartbreaking but distinct from the loss of object recognition. However, as dementia progresses, the impairment often extends beyond social memory to affect recognition of objects and their purposes. This means that a person with dementia might see a common object, like a toothbrush or a remote control, but fail to remember what it is used for or how to use it. This is because the disease disrupts the brain’s ability to link the object’s appearance with its function, a process that involves multiple brain areas including the hippocampus and cortex[4].
The loss of object purpose recognition is part of a broader cognitive decline that includes difficulties with memory precision—the ability to recall detailed and accurate information. Studies show that even in early stages of cognitive aging, memory precision declines, making memories less detailed and more prone to errors. This decline affects not only long-term memory but also short-term and perceptual memory, which are essential for understanding and using everyday objects correctly[6].
From a medical perspective, the underlying mechanisms involve complex changes in brain chemistry and structure. For example, enzymes called matrix metalloproteinases (MMPs) become overactive in Alzheimer’s disease, leading to the breakdown of perineuronal nets. Experimental treatments that inhibit these enzymes have shown promise in animal models by preserving these nets and delaying memory loss, including social recognition[2][3]. While these findings are preliminary and mostly in mice, they offer hope for future therapies that might slow or prevent the loss of object and social memory in humans.
In addition to structural damage, dementia also causes astrogliosis—an abnormal increase in certain brain cells called astrocytes—which can disrupt the cholinergic system involved in memory and cognition. This contributes to recognition memory impairment without necessarily causing immediate neuron loss, indicating that early intervention might protect brain function before irreversible damage occurs[4].
In practical terms, when a person with dementia forgets the purpose of common objects, it reflects a breakdown in the brain’s ability to connect sensory information (what the object looks like) with stored knowledge about its use. This can lead to confusion, frustration, and difficulty performing daily tasks. Caregivers often notice that patients might hold an object but not know what to do with it or might use it incorrectly.
Understanding these changes helps explain why dementia affects people in such specific and sometimes puzzling ways. It also underscores the importance of supportive care strategies that compensate for these memory losses, such as labeling objects, simplifying environments, and providing step-by-step guidance.
The research into perineuronal nets and memory precision is ongoing, and while current treatments for dementia focus on symptom management, these new insights open avenues for potential disease-modifying therapies. For now, recognizing that forgetting the purpose of objects is a common and medically grounded symptom of dementia can help families and caregivers respond with patience and appropriate support.
Sources:
[1] New Atlas, “New target to prevent Alzheimer’s patients forgetting loved ones,” 2024
[2] The Pathologist, “Why do Alzheimer’s patients forget their loved ones?” 2025
[3] Study Finds, “The Cruelest Alzheimer’s Symptom May Finally Have Explanation,” 2024
[4] PubMed, “Temporal Progression of Recognition Memory Impairment,” 2023
[5] Full Bloom Memory Care, “Why Loved Ones Living with Dementia No Longer Recognize Us,” 2025
[6] Medical Device Network, “Study uncovers the first subtle sign of dementia,” 2024
