Understanding Dementia: It’s More Than Memory Loss

Dennis Fitzgerald, MD
July 21, 2026

Southcoast Health’s Memory Care program recently marked its first year of serving patients and families across the South Coast. In this Expert Insights article, Dr. Dennis Fitzgerald, who leads the program, explains what dementia really is (and isn’t), why an accurate diagnosis matters, and what you can do today to protect your brain health.

A Growing Challenge

An estimated 7.4 million Americans age 65 and older are living with Alzheimer’s dementia today, and Alzheimer’s is only the most common cause of dementia, not the only one. Deaths from Alzheimer’s disease have more than doubled since 2000, and the number of people affected is expected to nearly double by 2060. Behind every diagnosis is a family: nearly 13 million Americans provided over 19 billion hours of unpaid care to a loved one with dementia in the past year.

What Is Dementia?

Cognitive impairment exists on a spectrum separated between subjective cognitive impairment, mild cognitive impairment and major neurocognitive disorder (e.g., dementia).

• Subjective Cognitive Impairment refers to when you feel like your memory or thinking is slipping, even though standardized testing doesn’t show objective deficits.
  
• Mild Cognitive Impairment (MCI) means there are real, measurable changes in memory or thinking, noticeable to you or your family, but you can still manage your daily life independently.
  
• Major Neurocognitive Disorder (the formal term for dementia) means those changes have progressed to the point where they interfere with activities of independent living like managing finances, keeping track of medications, driving safely, or preparing meals.

These terms describe how much thinking has changed and how this interferes with your daily function. They don’t tell us why. This is why dementia is an “umbrella term” – a categorical description that doesn’t ascribe a cause. Identifying the underlying cause is the job of a careful evaluation, because the “why” determines the treatment, and sometimes the cause is treatable.

Neurodegenerative Causes

Alzheimer’s disease is the most common cause of dementia. It typically begins after age 65, though it can appear in people in their 40s or 50s. The hallmark is short-term memory loss: repeating the same questions, forgetting recent conversations, misplacing items. Notably, some patients genuinely cannot perceive their own memory loss and may become defensive or even confrontational when family members bring it up.

Lewy body disease (LBD) is critically underrecognized and often undiagnosed, despite being the second most common cause of dementia, and can often co-occur with Alzheimer’s disease. Further, the symptoms are much more responsive to treatment with typical Alzheimer’s drugs like donepezil – even more responsive than those with Alzheimer’s alone. Lewy Body Disease comes in two forms:

• Parkinson’s disease dementia, where a person has Parkinson’s for years before cognitive changes develop.
• Dementia with Lewy bodies, where cognitive changes appear before movement symptoms.

In both forms, the features are distinctive: visual hallucinations, visual distortions (mistaking one object for another), acting out dreams during sleep, fluctuations with days of seemingly normal thinking interspersed with periods of confusion and drowsiness. Neuropsychiatric changes, like new-onset depression, anxiety or psychosis, are common. Patients with LBD may also become confused about their medications.

Frontotemporal dementia (FTD) tends to strike younger people, often between 45 and 65. Some variants affect language first: speech may become halting and effortful, or a person may struggle to find words or mispronounce common words. Another variant changes a patient’s personality, with apathy, loss of social graces, and impulsive decisions. This is a particularly tragic condition because it usually affects patients in the prime of life and may be perceived as a moral failing by patients’ families.

Vascular cognitive impairment is the result of recurrent strokes, sometimes large, sometimes tiny and silent, that cumulatively damage the brain’s wiring. Often patients appear “slower” while walking, talking, or thinking, and may have trouble focusing on more than one task at a time.

When Dementia Is Reversible

Not everything that looks like dementia is neurodegenerative. When evaluating patients, Southcoast Health’s Memory Care program searches for treatable causes, including:

• Vitamin deficiencies. Low vitamin B1 or B12 can impair memory and thinking.
  
• Thyroid disease. An underactive thyroid can slow both body and mind.
  
• Medical conditions. Chronic kidney disease, liver disease, and other illnesses can reduce the brain’s efficiency and cloud cognition.
  
• Medications. Sedatives, sleep aides (such as Benadryl, a common ingredient found in Tylenol PM), bladder medications, older allergy medications, and other common prescriptions can interfere with normative brain function, especially in combination.

Reducing Your Risk: What the Science Says

Research suggests that up to 45% of dementia risk is tied to factors within our control.

In a recent large-scale study, participants who followed a structured program of regular aerobic and resistance exercise, the brain-healthy MIND diet, regular cognitive challenges and social engagement, and routine preventive care showed significantly greater improvement in cognitive function than those given the same advice to follow on their own.

Two lessons stand out. First, lifestyle changes work. Second, structure and accountability matter; the group with coaching, goals and teammates outperformed the go-it-alone group.

Simple brain-friendly steps you can start now:

• Get moving: aim for aerobic exercise most days of the week, plus strength training
• Eat for your brain: the MIND diet emphasizes leafy greens, berries, nuts, fish and olive oil
• Challenge your mind: learn, read, puzzle, and stay curious
• Stay connected: social engagement is brain exercise, too
• Know your numbers: control blood pressure, cholesterol, and blood sugar
• Talk with your doctor about your personal risk

Memory Care at Southcoast Health

If you or a loved one is experiencing changes in memory or thinking, you don’t have to navigate it alone. Southcoast Health’s Memory Care program provides comprehensive cognitive evaluations to establish an accurate diagnosis, including identifying the reversible causes described above.

Southcoast Health also participates in GUIDE (Guiding an Improved Dementia Experience), a Medicare program designed to support people living with dementia and their caregivers. For eligible patients, GUIDE provides access to a care navigator available 24/7, caregiver training and education, and respite care benefits of up to $2,500 per year, giving caregivers the chance to rest and recharge.

Learn more about the Memory Care program at Southcoast Health Brain & Spine.