A collection of symptoms caused by disorders that affect the brain and cause significant problems with cognitive function, including memory loss.
Memory is defined as the faculty of encoding, storing, and retrieving information. The classical multi-store model of human memory suggests that memory can be categorized and stored into three important systems: sensory (SM), short-term (STM), and long-term (LTM). Different category of memory plays different role in storing certain information in our brain. SM has a very large capacity, but the information rapidly decays and is only stored for a few 100 ms. A portion of SM that has not been decayed will be transferred into STM, which can store memories for a few seconds. However, the capacity of STM is relatively smaller than SM. Lastly, the minor part of the STM will be transferred and stored for a lifetime in LTM (Tripathy & Öǧmen, 2018).
Memory loss is the failure or inability to recall past events or knowledge. The loss of memory can be partial or total, depending on the extent of memory loss. Forgetfulness is typically mild and is experienced by almost everyone at some point in life. Amnesia is a total loss of memories including name and personal history. Most people experience memory loss due to the normal aging process. However, there are also different causes that cause a more severe or earlier onset of memory loss that may need treatment and support. The common types of memory loss are as follows:
- Age-associated memory loss: Also known as age-associated cognitive decline, aging contributes to the decline in memory performance.
- Delirium: An acute disturbance in cognition or mental capabilities and reduced awareness of the environment, usually resulting from an underlying medical condition or from medication or drug withdrawal.
- Dementia: A collection of symptoms caused by disorders that affect the brain and cause significant problems with cognitive function, including memory loss. Alzheimer’s disease (AD) is the most common cause of dementia although there are other possible causes of dementia. Alzheimer’s disease is a progressive disease, meaning that early symptoms are mild but slowly become worse. Typically, it begins with a subtle and poorly recognized failure of memory and slowly becomes more severe until it eventually becomes incapacitating (Brejjyeh & Karaman, 2020).
- Drug effects: Some of the commonly used therapeutic medications and several recreational drugs are known to cause memory disturbances. One of the well-known examples of a drug that causes amnesia is benzodiazepines.
- Mild cognitive impairment: Mild cognitive impairment (MCI) is regarded as the transitional period between the normal cognitive decline of healthy aging and dementia (Anderson, 2019).
The risk factors for memory loss vary from one individual to another. It can be further classified into non-modifiable and modifiable risk factors. Non-modifiable risk factors are factors that cannot be changed or modified while modifiable risk factors can be altered through lifestyle choices.
The non-modifiable risk factors are as follows:
- Age – The risk of developing dementia increases when we age.
- Genetics – Some dementia is associated with specific genes.
- Family history – The risk of developing dementia increases with the presence of a family history (Loeffler, 2021).
While some of the modifiable risk factors are as follows:
- Education – One of the early-life factors that affect the resulting cognitive reserve.
- Physical health – Individuals with good physical health can sustain a higher burden of neuropathology without cognitive impairment.
- Smoking and air pollution – Enhancement in reactive oxygen and inflammatory response (Hughes & Ganguli, 2009).
- High alcohol intake – More than 21 units of alcohol intake per week increases the risk of memory loss and dementia (Livingston et al., 2020).
- Depression and social isolation – Both factors are associated with accelerated brain and cardiovascular aging (Cacioppo et al., 2011).
- Medications – Certain drugs such as benzodiazepines cause memory impairment and disturbances such as benzodiazepines.
Some memory loss is reversible, and some are not. The treatment for memory loss depends on the cause and severity. It is important to find out the root cause of reversible memory loss and stop the triggers. For example, as previously mentioned, medications such as benzodiazepines and depression cause memory loss. Hence changing the medications and treating depression may resolve memory loss.
However, there is currently no drug treatment that is available to cure memory loss. The medications that are currently available are only used to ease the symptoms and manage the condition’s progression (only approved by the FDA for Alzheimer’s disease-related dementia but not for the other types of memory loss). The following medications are currently used to treat symptoms related to memory and thinking:
- Cholinesterase inhibitors: Used to prevent the breakdown of acetylcholine associated with memory and learning. Examples of drugs are donepezil, rivastigmine, and galantamine.
- Glutamate regulators: Regulating the activity of glutamate that helps the brain to process information. An example of a drug is memantine.