As a neurologist I frequently see patients who complain of memory impairment and forgetfulness. Some consult me primarily for this problem; many others who have come to consult me for some other problem such as headaches voice this concern during the course of their patient interview. All are concerned that they may have dementia. So in this post I shall discuss dementia. In keeping with the style of writing on this blog, I shall keep it simple and free of excessive medical jargon.
So what is dementia?
Broadly speaking dementia may be defined as a disorder in which a person experiences problems in multiple cognitive domains. So for example a patient who has moderate Alzheimer’s dementia shall experience problems with memory (cannot recall old information and may not be able to make new memories), speech (speech is sparse, vocabulary is markedly decreased), may experience problems with calculation, concentration, executive functioning (such as planning for the future), balancing his check book and learned tasks (such as tying his shoelaces, driving a car, using a spoon to eat, brushing his teeth). Family and friends may notice a change in personality (patient might becomes disinhibited, aggressive, argumentative or quieter and mute) and behavior (disruption of sleep wake cycles, night time wandering and so forth). A point to note here is that the motor and sensory parts of the brain remain largely intact so the patient is not weak if formal strength testing is carried out. The disease predominantly affects the higher mental functions—that is the functions which separate us from animals and make us so unique as a species—aka our ability to think, to calculate, to remember, to speak and our individual personality and behavior.
How does dementia present in the early stages?
The onset of dementia is usually subtle. In the early stages of the disease, the patient appears “normal”. Social graces are maintained. Appearance remains well groomed and if you meet such a person casually at a party you shall not mind anything miss. The patient also remains independent in all activities of daily living (ADLs) for example he can brush his own teeth, wear his clothes without any help, drive or take a bath. They may also be able to maintain/keep their jobs. This stage has been referred to minimal cognitive impairment or MCI for short. Further on from here things become trickier. A person may remain in MCI stage and not progress further or progress very very slowly. We still do not know the reason for this. Why some patients remain in MCI stage and do nor progress further. Others may advance on to frank dementia. Why this occurs in some patients rather abruptly and quickly as compared to others is still not known. As the patient advances from moderate to severe dementia he becomes progressively more and more dependent on care givers for ADLs. In the late/final stages of dementia, the patient is bed bound, mute, totally dependent on care givers, stiff and incontinent of both urine and feces. Death usually occurs due to superimposed infection such as pneumonia, sepsis or a urinary tract infection.
Are there different types of dementia?
There are indeed many different types of dementia: Alzheimer’s dementia, frontotemporal dementia (Pick’s disease), diffuse Lewy body dementia, dementia of Parkinson’s disease, vascular dementia and so forth. A dementia like clinical picture may also result from certain infectious diseases such as AIDS dementia complex also called HIV encephalopathy and mad cow disease. Vitamin B12 deficiency, hypothyroidism, chronic alcoholism, syphilis are other conditions which may cause a picture indistinguishable from primary dementias such as Alzheimer’s disease. It is important that these be looked for and ruled out since they are treatable causes of memory impairment. If depression is present, it should be identified in a timely fashion, treated and then the patient should be reassessed.
A point to note here is that all the above mentioned conditions present clinically in much the same fashion. It is indeed quite difficult if not impossible to make a definitive diagnosis such based on history and examination findings as clinical features overlap. Ancillary tests such as MRI brain, PET and SPECT scans may help to narrow the differential diagnosis. In the near future we remain confident that we shall be able to diagnose the different types of dementia more accurately and more importantly early on in the disease course.
How is dementia diagnosed?
The diagnosis of dementia till today remains predominantly clinical. By that I mean that the diagnosis is made after taking a thorough history and after considering the examination findings. In my personal experience I have found a good neuropsychological evaluation conducted by an experienced neuropsychologist as particularly helpful. MRI brain, PET and SPECT scans are helpful and may help narrow the differential diagnosis and in ruling out other conditions which may mimic dementia. A EEG study is useful and helps to collaborate the examination findings. There is a tremendous thrust to identify biomarkers for dementias such as Alzheimer’s disease both in the blood and the cerebrospinal fluid (CSF). In the same vein, MRI biomarkers are also getting close inspection and may be ready for clinical use in the near future.
How is dementia treated?
Primary dementias such as Alzheimer’s disease, frontotemporal dementia and dementia of Lewy body are progressive neurodegenerative conditions. At present we have no cure but there are drugs available which may slow down the rate of cognitive decline and ensure better quality of life both for the patient and the family members who care for them. None though is a magic wand and none work once the dementia is moderate to severely advanced. Research continues at a feverish pace and I remain confident of a breakthrough in my lifetime.
Can dementia be prevented?
Or rather can I take any steps now so that I do not get dementia in my later years? Many drugs, herbal and other supplements have been looked at, tested but none have shown a consistent benefit. High dose vitamin E supplementation did not work. Gingko does not work. This is what I advice my patients:
If they have vascular risk factors such as hypertension, diabetes mellitus or high cholesterol, these should be aggressively controlled.
Do not smoke and if you do—stop.
If you do have vascular risk factors, speak to your doctor about taking a tablet of baby aspirin daily. Follow his advice.
Exercise, exercise, exercise. There is ever more research that exercise is neuroprotective.
If you are big on supplements, I advice taking Vitamin B12 500 micrograms once or twice daily and fish oils (omega 3 fatty acids). Again speak to your doctor before you take any supplements.
Attacks of major depression “hurt” the brain. So depression should be identified and treated.
Nitin K Sethi, MD