Overview
Huntington Disease is a neuropsychological disorder characterised by neurocognitive impairments. These impairments usually start around 60 years of age and get progressively worse over time.
Memory loss is the hallmark of Alzheimer’s Disease. The person may be forgetful, confused and causing distress especially in social functioning. In certain variants, language disturbance may be noticed, it is known as logopenic aphasia. Visuospatial memory and function may also be affected. The onset is insidious, with simple forgetfulness, but then it gets progressively worse over time causing dementia.
In Alzheimer’s, the deficits can be major or mild. This distinction is based on the impairment and the level of assistance required for the person to carry out day to day activities. Major deficits mean greater impairment and assistance with most basic day to day activities while mild deficits mean lesser assistance and the person can carry out basic day to day activities.
Individuals with Alzheimer’s have certain gene mutations that cause the brain to atrophy which leads to cell loss. Neurofibrillary tangles and senile plaques are also seen in AD patients. These are also seen in neurodegeneration happening due to age related factors. However, the location of these largely determine the presence of AD. In AD, neurofibrillary tangles are mostly seen in the hippocampus which is associated with memory processing.
Genetic mutations are seen on the gene Apolipoprotein E and its variants. It causes excessive production of the amyloid protein causing plaques. Another protein associated is known as protein tau which causes neurofibrillary tangles in the brain.
The symptoms usually affect social cognition due to memory loss. They may have trouble recognising loved ones which causes a lot of distress to the caregivers or close ones of the individual.
Common Signs and Symptoms
Common Signs and Symptoms include:
- Forgetfulness and memory loss.
- Cognitive decline characterised by trouble with learning new tasks, executive functioning, decision making, remembering things, etc.
- Difficulty concentrating, confusion, inability to create new memories, etc.
- They may get aggressive, agitated or restless.
- In severe cases, they may need assistance with day to day activities.
Risk Factors
Genetic mutation of the gene Apolipoprotein E is associated with the development of Alzheimer’s Disease. This gene is associated majorly with synaptic repair and maintenance of neuronal structure and cholinergic function.
It is considered as a risk factor but not 100% associated with the development of AD. Individuals without the gene mutation also get AD.
Environmental factors associated with this disorder include Brain Injury or cerebrovascular disorders. Reducing risk for cardiac disorders significantly also lowers risk of developing AD.
In individuals with Down Syndrome, AD may develop in later stages of life. Aging is also associated with the development of AD.
Diagnosis
This disorder is usually diagnosed by a neuropsychologist. A neuropsychologist will perform adequate assessment of the person’s neurocognitive and emotional function.
Alongside neuropsychological testing, various imaging techniques are used to scan for the presence of Alzheimer’s Disease. MRIs, PET scans, Cerebrospinal fluid testing, etc.
Most recent and non-invasive method of imaging for AD is done through injecting radio labeled tracer agents. This helps in detection of amyloid related plaques in the living brain as seen on a PET scan. It has around 95% accuracy in detection of AD.
To be diagnosed with Alzheimer’s Disease, following criteria must be met:
- Forgetfulness and problems with memory and cognition.
- Inability to form new memories and issues with learning new things.
- Mood alterations causing aggression, irritability, etc.
Neuropsychologists are required to rule out other medical conditions or substance use that may cause similar symptoms.
Treatment
Treatment options for AD are limited to supportive care and symptomatic treatment. Cholinergic treatment such as cholinesterase inhibitors are administered to patients with Alzheimer’s Disease and Parkinson’s Disease Dementia. Donepezil, rivastigmine, or galantamine are commonly used for the treatment of cholinergic deficits.
In patients that show difficulty with attention and alertness, N-methyl-D-aspartate receptor antagonist and a dopamine agonist, is administered.
Patients may also be prescribed nutraceutical huperzine A. Administration of this drug has shown efficacy in day to day performance among AD patients. However, it may cause side effects such as depletion of Vitamin D levels which may be supplemented externally.
Risk of cardiovascular diseases is known to increase the risk of cerebrovascular diseases as well Alzheimer’s Disease. Hence, in order to reduce the risk, simple lifestyle related measures can be considered. Staying on Mediterranean diet (meals consisting of fresh produce, wholegrains, olive oil, legumes, and seafood while limiting dairy and poultry products and avoiding red meat, sweets, and processed foods), aerobic exercises, recreational physical activities, etc are measures taken to reduce cardiac disease risk and AD risk.
Research targeting treatment of AD with directly targeting senile plaques and neurofibrillary tangles and prevention of them or reducing generation capacity of the same is still ongoing.
Differential Diagnosis
- Other neurocognitive disorders: Major and mild neurocognitive disorders seem to have the same symptoms and progress as Alzheimer’s Disease. But, the basic characteristics of both differ.
- Active neurological or systemic illness: It may be difficult to differentiate Alzheimer’s Disease from other neurological or systemic illness. But, if clinical evidence suggests something slightly different then Alzheimer’s Disease, neurological or systemic illness must be considered.
- Major depressive disorder: Depression is also known to cause reduced functioning and distubed concentration, but the improvement in the depressive state makes it clear of the presence or absence of Alzheimer’s Disease.
Comorbidity
Alzheimer’s Disease is majorly noted in the geriatric population who have multiple medical conditions due to which, diagnosing them with Alzheimer’s Disease can be difficult and may take time to identify. Major or mild neurocognitive disorders are a result of cerebrovascular diseases.
Specialist
A neurologist, neuropsychologist or neuropsychiatrist are often referred to for treatment.
