Dementia is a general term that encompasses a group of neurological diseases affecting the brain that result in the deterioration of two or more areas of higher cognitive functions.
Its prevalence is estimated at 13.5-15% of the population over 65 years of age. This percentage increases to 30-33% in those over 85 years of age and jumps to 50-55% in those over 90 years of age. It is the most frequent cause of mental deterioration in old age.
There are several and varied definitions of dementia. An acceptable definition may be that of Professors Lishman and Ron: “global and acquired deterioration of intellectual functions, memory and personality, which interferes with the social and occupational functioning of the individual and in which the level of consciousness is maintained normal.”
Types of dementia
Alzheimer’s disease is the most common dementia (40-50%), followed by vascular dementia (15-20%), Lewy corpuscles (10-15%) and the rest (Parkinson’s disease, Huntington’s chorea, progressive aphasia, etc.) make up the remaining 10-15%.
Sometimes it is difficult to distinguish one from the other, especially in middle and advanced stages. In more than 30% of cases they overlap with each other, forming what is known as mixed or multimodal dementia.
Symptoms
The essential symptoms are:
1. memory impairment, which is usually the predominant symptom.
2. Impairment of abstract thinking and logical reasoning (inability to find and differentiate between related words, difficulty in defining words and concepts).
3. Impaired judgment (inability to take reasonable action on issues and problems related to work, social or family contacts. The ability to control impulses is also affected).
4. Disorder of higher cortical functions: aphasia (loss of ability to produce and understand language), agnosia (inability to recognize previously learned stimuli) and apraxia (dissociation between desire to perform a movement and motor execution).
5. Personality changes: withdrawal, apathy, delusions of theft, jealousy (uncontrolled jealousy), uninhibited behavior, etc.
6. Normally there is no disorder of the level of consciousness.
Causes
Dementias are classically divided into primary and secondary:
1. Primary dementias are those whose cause is in the brain (Alzheimer’s disease, frontal dementia, frontotemporal dementia, etc.).
2. Secondary or pseudo dementias are those caused by hormonal deficits (hypothyroidism), hormone excess (hyperthyroidism or hyperparathyroidism) or reversible psychiatric disorders such as depression, toxic (metal intoxication, renal or hepatic encephalopathy).
They can also be divided into senile/presenile depending on the age of onset, cortical/subcortical depending on which area of the brain is most affected, reversible/non-reversible depending on whether the causative entity and underlying damage are curable or not.
Some factors have been associated with an increased risk of developing dementia. Age is the most important risk factor. The second most important factor is having a first-degree relative with dementia (3.5 times higher risk of developing dementia).
The only gene clearly implicated in Alzheimer’s disease is the E4 allele encoding the APOE gene, which is found in 10-15% of the European population but in 45-50% of Alzheimer’s patients.
Head injuries, physical inactivity, drug use, low cultural level and a maladaptive personality are other factors that have been studied that may facilitate the development of dementia.
Factors thought to decrease the risk of dementia include low/moderate alcohol consumption, Mediterranean diet, antioxidants (vitamin E, vitamin C) and unsaturated fatty acids. Regular exercise and exercising the mind are also activities that decrease the risk of dementia.
Treatment
There is currently no effective treatment for dementia. Two groups of drugs are used routinely and almost as a compassionate treatment:
1. ACE inhibitors (acetylcholinesterase inhibitors/act on the acetylcholine pathway). They are used in early and intermediate stages of the disease.
2. NMDA (non-competitive N-methyl-D-aspartate receptor antagonists/glutaminergic pathway). Used in more advanced stages of the disease.
They can be used in conjunction with other drugs used to mitigate the effect of behavioral and psychological symptoms of dementia in young patients in whom the IACE has not been effective. The main ones are:
1. benzodiazepines (mostly for anxiety and insomnia) 2.
2. SSRIs (antidepressants of the serotonin reuptake inhibitor type; they are used in case of anxiety, agitation or apathy).
3. Antipsychotic drugs (used at low doses in the case of behavioral symptoms, delusional ideations, auditory delusions, etc., although they have not been shown to increase the patient’s quality of life or decrease mortality).
In the case of non-pharmacological therapy, the first place is occupied by psychostimulation: reality orientation, cognitive stimulation, cognitive training, ABVD training, reminiscence therapy, music therapy, aerobic exercise, combined global stimulation.
Another interesting section are therapies dedicated to caregiver wellness: education, counseling, support programs, respite care, case management and family support therapy.
In the case of dementia it is very important to be advised by an expert to approach the disease holistically (bio-psycho-social): make an accurate diagnosis, classify the stage and develop a therapeutic plan (usually multidisciplinary) for the patient and family/caregivers, adapted to each stage of the disease.
The therapeutic plan should also take into account cognitive capacity, functional dependence, behavioral disorders and decision making, such as non-renewal of driving license, judicial incapacitation, legal guardianship, advance directives, limitation of therapeutic effort, etc.