DEMENTIA

DEMENTIA

It is progressive generalized impairment of intellectual functions and memory without impairment of consciousness. 

Dementia is classified as:

1. Alzheimer’s type
2. Vascular dementia: Vascular dementias are sub classified as: a. Those with an acute onset, b. Multi infract dementia, c. subcortical vascular dementia.

3. Dementias in other diseases like Pick’s disease, Creutzfeldt–Jakob (CJ) disease, Huntington’s disease, Parkinson’s disease and HIV disease.

Specific Impairment

1.      Organic Hallucinosis [Causes: Substance abuse (alcohol, cannabis, LSD-Lysergic Acid Disethylamide), Temporal lobe tumors, etc.]

2.      Organic Catatonic Disorder [Causes: Encephalitis, Carbon monoxide poisoning, Neoplasms, etc.]

3.      Organic Delusional Disorder [Causes: Substances abuse (cannabis, amphetamines, and alcohol), Temporal lobe lesions etc.]

4.      Organic Mood Disorder [Causes: Infection, Endocrine disorders, Brain lesions and drugs like steroids and antihypertensives]

5.      Amenstic Syndrome: Amenstic disorders are characterized by severe memory impairment for recent events. Long term memory is sometimes affected. Immediate recall of events is normal, as are the other cognitive functions. The patient is alert and the conversation can be carried out normally. Learning of new materials is grossly affected. Secondary to the memory impairment there may be disorientation of time. Gaps in the memory are filled with confabulation. [Causes: Alcohol abuse and thiamine deficiency. Gastric carcinoma and dietary deficiencies resulting into thiamine deficiency produces amnestic syndromes. Damage to diencephalic and medial temporal structures (mamillary bodies, fornix, hippocampus) as a result of surgery or trauma, anoxia, infarction, infections, carbon monoxide poisoning or neoplasms of the third ventricle result in Amenstic syndromes]

6.      Personality Changes [Causes: Frontal lobe lesions, Encephalitis, Concussions, etc.]

Impairment due to Focal Brain Damage

1. Frontal Lobe Syndrome: Personality Changes: – Socially disinhibited (e.g.: urinate in public), Inattentive and easily distractible, slow and non-spontaneous, careless in dress, eats voraciously and general efficiency deteriorates. Generalized convulsions may occur. Memory and Intellect may not be impaired. Neurological deficits accompany depending on the area affected.
2. Temporal Lobe: Some temporal lobe lesions are asymptomatic but they are usually accompanied by personality changes. There is greater intellectual impairment, irritability and aggressive, epilepsy, schizophrenia, learning impairment and neurological deficits.
3. Parietal Lobe: Personality changes are uncommon but sensory defects are marked. Right-left disorientation, agnosias and dysphasias are also seen. Right-left disorientation, finger agnosia, agraphia and acalculia are together called Gerstmann’s syndrome.
4. Occipital Lobe: Visual disturbances (Lemianopias, loss of colour vision and loss of vision) and complex visual hallucinations are seen. Personality changes are uncommon.
5. Mid brain and Thalamus: Lesions of the third ventricle, mid brain, thalamus brings about personality changes, characterized by diminution of initiative, regression to a childish state and fatuous jocularity. There is deterioration of personal habits.