What Is Dementia?

Dementia is a neurodegenerative disorder where the brain gradually loses several aspects of its function. While the most common symptom is memory loss, there is gradual impairment of several other brain functions where often the person ends up being unable to look after his own affairs.

Although this is a global syndrome there are actually many different kinds of dementia which differ from each other in terms of types of brain function affected, speed of progression and prognosis.


Most Common Forms of Dementia


  • Alzheimer’s Disease: Most well-known and commonest among the dementia syndromes Alzheimer’s disease accounts for 2/3rd of all dementias worldwide. Apart from memory most commonly the higher functions like ability to bank, ability to use modern technology like mobiles and remotes, driving, cooking etc. are affected in this disease.


  • Vascular Dementia: This dementia syndrome is related to lack of blood flow in the small blood vessels supplying deep areas of the brain. Usual risk factors are Blood Pressure, diabetes, high cholesterol, smoking, Diabetes etc. Memory is less affected in this syndrome and higher and intelligent functions are more commonly affected.


  • Lewy Body Dementia: This form of dementia occurs due to deposition of an abnormal protein called Lewy Body which results in shrinkage and loss of function of those areas of the brain. Visual hallucination (seeing objects and persons), aggression, agitation and motor symptoms of parkinsonism (stiffness and slowness) are hallmarks of this disease.


  • Parkinson’s Disease Associated Dementia: Parkinson’s disease patients over time develop memory impairment and a syndrome of dementia which is often very closely related to symptoms to Lewy Body dementia.


  • Frontotemporal Dementia or Niemann/Pick’s disease: This form of dementia causes loss of function of specifically frontal and temporal lobes of brain. Abnormal social behaviour, personality changes and speech impairment are common symptoms of this syndrome which unfortunately is very rapidly progressive.


  • Uncommon Causes: Many patients especially the older ones beyond 80 years have more than one cause contributing to their dementia. These are called Mixed dementias. Cumulative and gradual damage to brain from Chronic alcoholism (Korsakoff’s syndrome) and recurrent head injury (common in boxers and footballers) can also cause dementia. Rare conditions called Prion diseases (infections of brain with foreign virus like proteins) can cause Creutzfeldt-Jakob disease which may present as atypical aggressive dementia syndrome.

Risk Factors

  • Age: Dementia classically is a disease of the elderly, and there is a common belief within the medical fraternity that of we all lived enough we all will develop dementia one day.


  • Family History: Certain forms of dementia like early onset Alzheimer’s disease (before 70 years of age) tend to run in families. Researchers have found a particular gene called APO E4. About 50% of patients with this gene develop Alzheimer’s disease by age 90. This does NOT mean that if a person has dementia then their children will develop dementia.


  • Vascular Risk Factors: Smoking, diabetes, blood pressure and high cholesterol are thought to be risk factors for developing vascular dementia.


  • Lifestyle Factors: People with higher education, better social skills remain more engaged mentally and this seems to have a protective element.


The most important aspect of the diagnosis of dementia is the timeline described in history. The hallmark of a dementia syndrome is the slow onset of symptoms and a very gradual decline. It is never of sudden onset over a day or two but seems to come on over months to years. Also, the patient with dementia in the early and middle stages of the disease remains physically well.


Dementia represents a gradual decline in global brain function across many areas including speech, memory, language, reasoning, judgment etc. The symptoms with each form of dementia are often slightly different but this may only be recognisable to skilled healthcare providers who have experience working with people with dementia. Sometimes family members notice changes but mistakenly blame them on old age.


Early changes: The earliest symptoms of dementia are gradual and subtle. Many people and their families first notice difficulty remembering recent events or information (short term memory loss). Others can include the following.


    • Confusion (gradual onset)
    • Difficulties with language, like not finding the right word or not understanding speech of others
    • Difficulty with concentration and reasoning
    • Problems with executive function or complex tasks (driving, banking, cooking etc.)
    • Getting lost in familiar places


Late Changes: As dementia progresses the symptoms gradually worsen and often include behavioural and personality changes. The physical wellbeing of the patient also starts to decline gradually with increasing frequency of infections. Physical symptoms like appetite and weight loss and incontinence mark advanced stages of the disease.


    • Increased anger, hostility, and aggressive behaviour; alternatively some people become very passive
    • Hallucinations and/or delusions
    • Disorientation
    • Needing help with basic tasks (eating, bathing, dressing)
    • Incontinence (leaking urine or faeces without knowing)

The speed at which symptoms develop and decline vary in different persons. In the majority of cases the disease reaches advanced stages by 7 years from diagnosis. Most people with dementia do not die from the disease itself, but instead from a secondary illness such as pneumonia or urinary infection.

Investigations & Treatment

  • Mental Tests: There are several tests available to test a person’s memory and functioning of brain. They test various actions of the brain like memory, analytical skills, naming, recognising objects, speech formation and complex multitasking. Common tests include Abbreviated Mental Score (AMT, a 10 point score), MMSE (a 30 point score) and MOCA (a 30 point score).A full neuropsychological assessment is also very helpful but is time consuming and may need up to 2 hours.


  • MRI Brain: this may show shrinkage of certain areas of the brain and help in diagnosis of the type of dementia. 


  • Blood tests: Certain causes of dementia are reversible like vitamin deficiencies, underactive thyroid gland, infections like syphilis etc.  Blood tests to find out any reversible causes should be done.


Treatment For Dementia

  • Acetylcholine Esterase Inhibitors: There are three medicine called Donepezil, Galantamine and Rivastigmine available in this group. This treatment is effective only in Alzheimer’s Dementia and Dementia of Lewy Body. They do not cure the disease but offers some slowing down of the progression of symptoms over time.


  • Memantine: This medicine is again effective in Alzheimer’s dementia and Dementia of Lewy Body only; it may have some advantage in controlling agitation and aggression in dementia.


  • Blood Pressure and Cholesterol Control: These are important measures in controlling the progression of vascular dementia.


Dr. Dwaipayan Sen (FRCP(Glasgow) MRCP Geriatrics)

Consultant Stroke Physician, UK

How Consultation Works

  • Select How Would You Like To Consult

    Choose Between Online Or Video As Your Preferred Mode Of Consultation With The Consultant

  • Define Your Health Problems & Upload Necessary Reports

    In this section, upload patient details, medical history, current medications taken and the necessary report to discuss the case with the consultant

  • Pay & Book Your Consultation

    In this section you pay and book for your consultation

  • Consult With the Doctor

    With Online Query Consultation, the consultant replies to your queries within 24-48 hours from the time the consultation is booked.

    With Video Consultation, the consultant reviews your case and consults with you on the day the consultation is booked

Subscribe to our Newsletter