Cognitive Neuroscience: Compare and Contrast Single and Double Dissociation
Dissociation can be defined as separation of entire segments of the human sensory perception or personality. These conditions can be caused by varied external and internal influences. In cases of external injury (usually to the frontal lobe) there is loss of the episodic memory, yet preservation of semantic or procedural memory. With Semantic memory deficits one may have the ability to recall what specific items are used for, such as a towel used to dry the body, or a wheelbarrow used to push things. However the patient may loose all recollection of what characteristics are typical of living things. For example a bird would be a machine that carries people, or a snake a person who causes harm. Loss of episodic memory is loss of memory of personal memory and occurrences. Also labeled Amnesia.
Double dissociation is the loss of ability to identify non-living things. While living things are mostly characterized by their appearance, nonliving things are distinguishable by their function. The patient would have a difficult time distinguishing living from non-living functions.
There are patients who do not have the ability to name an object that they can see, but upon touching, feeling, and becoming physically familiar with the object they are able to categorize and classify it. Whereas another patient may have the ability to name an object, but not have the ability to know what the object is used for.
Other dissociative disorders derive through emotional trauma. These include self-mutilation, and multiple personality disorders. Multiple personality disorders often develop over years of repetitive trauma usually beginning in the early childhood stages. Self-mutilation disorders begin often in the pubescent stages or in some cases later in the adult life. An essential feature of these disorders is normally integrated functions, such as consciousness, identity, memory, or perception of the environment, dividing into separate functions and perceptions all together.
There are many types of dissociative disorders. Dissociative Amnesia is the perpetual loss of memory and function. One may experience episodic, and semantic memory loss. Dissociative Fugue is the confusion of personality and identity. Dissociative Identity Disorder (DID formerly labeled Multiple Personality Disorder) is one of the most extreme forms of dissociative disorders, in which the patient may internally create multiple personalities within his or her mind. Depersonalization is also an extreme yet common form of dissociative disorder in which the self-mutilation becomes the tool in defining reality for a patient.
We can conclude that dissociative disorders can be caused by external physical injury, or by internal and external psychological and emotional trauma and abuse. It is plausible to describe dissociative disorders connected to Amnesia are more often caused by external injury, while dissociative disorders such as Depersonalization and Dissociative Identity Disorder are moreover the effects of internal conflict and psychological abuse or trauma.
