What is Hippocampal Atrophy & How is it Treated?
The hippocampus is a part of the brain that helps in memory and spatial navigation. It is a small region of the brain situated within the medial temporal lobe, below the cortical surface. Anatomically, it is an extension of the cerebral cortex and is divided into 2 equal halves, each of which lies in the right and left side of the brain. The name hippocampus was derived from 2 Greek words, "hippo" which means horse and "kampos" which means sea, as the structure resembles a seahorse in shape.
The hippocampus helps in formation of long term memory. Any damage in the hippocampus can cause memory loss and disorientation. It can lead to condition such as Alzheimer's disease, amnesia, dementia etc. It is the first sign of any brain damage. Hippocampus damage can be caused by lack oxygen supply or hypoxia, infection, inflammation, trauma etc. Hippocampal atrophy is another condition that causes cognitive and memory dysfunction due to degeneration of the hippocampus.
What is Hippocampal Atrophy?
Hippocampal atrophy is a condition characterised by degeneration of the hippocampus. There is atrophy of the brain cells. It is one of the characteristic features of hippocampal sclerosis and Alzheimer's disease. Hippocampal atrophy causes memory deprivation and spatial disorientation. Hippocampus is also important for olfactory memory and hence atrophy in the structure leads to difficulty in identifying smell.
Function of the Hippocampus
- Memorization as a Function of Hippocampus: Hippocampus helps in the formation of new memories and retention of old memories. Severe damage to the hippocampus on both sides can cause serious memory issues such as anterograde amnesia. In cases where the damage happens due to trauma, there may be retrograde amnesia, i.e. loss of memory just prior to the traumatic event with or without retention of older memories. Hippocampal damage or atrophy does not affect the ability to learn new skills.
- Spatial Awareness and Navigation as a Function of Hippocampus: Hippocampus helps in cognitive mapping and helps in strengthening the sense of direction. Loss of function of the hippocampus or hippocampal atrophy can cause inability to remember direction and can lead to disorientation, confusion and being lost. It limits the ability to find ways.
Symptoms of Hippocampal Atrophy
Symptoms of hippocampal atrophy include:
- Memory loss including short term and long term memory loss based on the severity
- Difficulty recalling recent events
- Difficulty with spatial navigation
- Loss of direction and tendency to get lost in otherwise familiar environment
- Olfactory dysfunction
- Emotional disturbances
- Behavioural changes
Prognosis of Hippocampal Atrophy
Though prescription medication have shown to slow down the process and bring about certain amount of improvement in the symptoms and memory, no known definite cure for hippocampal atrophy has been found till date. A large number of studies are being carried out in view of the same.
Causes and Risk Factors of Hippocampal Atrophy
The causes of hippocampal atrophy are multi factorial. The most common causes include:
- Lack of oxygen supply or hypoxia is the most common cause and leads to death and degeneration of the brain cells.
- Skull injury or trauma can cause hippocampal atrophy.
- Long term stress or neurological disorders can lead to hippocampal atrophy. Certain neurological disorders such as multiple sclerosis, schizophrenia and epilepsy can lead to atrophy of the hippocampus.
- Other conditions such a Cushing syndrome, post-traumatic stress, depression and encephalitis can also cause hippocampal atrophy.
- Certain medication such as steroids, when used for a long term can alter the activity of neuron in hippocampus and can prevent regeneration of new neurons leading to hippocampal atrophy.
- Ageing can lead to degeneration of the brain cells.
Pathophysiology of Hippocampal Atrophy
Hippocampal atrophy is caused by loss or neurons secondary to neurofibrillary tangle formation. Due to this, there is partial to severe reduction in hippocampal volume. This loss of neuron or death of neuron causes hippocampal atrophy.
Diagnosis of Hippocampal Atrophy
Diagnosis of hippocampal atrophy includes through examination by a neurologist. Clinical examination includes memory studies and cognitive behaviour studies. Hippocampus function can be studied by measuring the frequency of electrical activity using an electroencephalogram (EEG). Investigative studies such as CT scan of the brain and MRI of the brain is also used for correct diagnosis and further evaluation.
Treatment of Hippocampal Atrophy
A large number of studies are being carried out to understand hippocampal atrophy and formulate treatment for the same. At present, treatment modality includes treatment of the underlying condition such as Alzheimer's disease, epilepsy, encephalitis, depression, stress etc. A combination of cognitive behaviour therapy and antidepressants may be suggested based on the condition. Psychotherapy with pharmacotherapy is used to treat at cognitive, physical and emotional level and also to bring about a balance. Certain brain exercises may be suggested for improving the memory.
Hippocampus is a seahorse shaped structure found in the medial temporal lobe of the brain. It helps in creation of new memories and spatial navigation. Hippocampal atrophy is a condition characterised by degeneration of the brain cells in the hippocampus leading to loss of memory and disorientation. It is seen to be associated with condition such as dementia, Alzheimer's disease, epilepsy, severe depression, schizophrenia, stress, Cushing syndrome etc. Till date, there is no definitive treatment modality at present for hippocampus atrophy and a large number of studies are being carried out to get a clear understanding of the condition. Symptomatic treatment plan for hippocampus atrophy includes a combination of cognitive behaviour therapy with prescription drugs such as anti-depressants. Drugs can help in management of the memory issues; however, complete cure of hippocampal atrophy is rare at present.