User:Clarke10e/sandbox

Aphantasia is a cognitive phenomenon defined as an individual's inability to voluntarily produce mental imagery. It is important to note that the definition specifies voluntary, as some individuals with aphantasia have the ability to produce vivid dreams. There are two types of aphantasia, which can be differentiated by the acquisition of the condition: congenital and acquired. Reports from individuals with aphantasia suggest that there is a correlation between aphantasia and the inability to recall sounds, smells, faces or sensations of touch.

The phenomenon of aphantasia was first described in 1880 by Francis Galton and was not further studied until 2010, when Adam Zeman created the definition for the term and research types of aphantasia.

Congenital Aphantasia
Congenital Aphantasia is the lack of ability to voluntarily produce mental imagery from birth that persists throughout one’s lifetime. Congenital Aphantasia was first studied in 2015 by Zeman et al, the participants all described their lack of voluntary imagery as a lifelong state.

Acquired Aphantasia
Acquired Aphantasia is categorized by a sudden loss of ability to voluntarily produce mental images in those who previously possessed the ability to produce them. Initially described in the study on Patient MX who lost his ability to create mental images after undergoing a coronary angioplasty. The onset of Acquired Aphantasia is suspected to be caused by acquired brain injury (ABI) such as a stroke. Additionally, studies suggest that Acquired Aphantasia can also be caused by psychosis and could be related to dissociative disorders which have links with depression.

History
Aphantasia was first described in 1880 by Francis Galton, in a study which assessed individual differences in mental imagery. Galton published a qualitative report looking at the vividness of participants’ mental imagery, taking into account the illumination, definition, and colouring of their mental image.

However, Aphantasia remained largely unstudied until 2010, when a paper by Zeman describing ‘Patient MX’ was released. Zeman (2010) described and investigated the possible causes of MX’s Aphantasia, which was first recorded after a coronary angioplasty. This paper sparked an interest in the field of Aphantasia, as a number of individuals reportedly approached Zeman reporting a lifelong inability to mentally visualise. Zeman and his team went on to publish an additional paper in 2015, which initially introduced the term Congenital Aphantasia and investigated the cognitive abilities of the individuals.

Blake Ross, a software engineer who helped create firefox published an essay describing his own experience with Aphantasia. Following on from this highly publicized report, in 2017 a book was published titled ‘Aphantasia: Experiences, Perceptions, and Insights’, which featured first-hand accounts from individuals with Aphantasia on their perspectives of living with aphantasia. In May 2018 The Aphantasia Network was created, aided by Zeman, to form a community of people with Aphantasia. This network was formed so that individuals could share their own personal experiences and any individual experiences to learn more about aphantasia and its effects.

In 2019, Tweens paper discussed whether Aphantasia could be a type of Synesthesia, and how there is a link between aphantasia and other types of inhibited sensory recall. Furthermore she went on to discuss that  whether an inability to mentaly crete senses should be named ‘Full Aphantasia’ could be a term which describes full sensory deficits.

Assessment
In Zeman's original paper on Aphantasia, the Vividness of Visual Imagery Questionnaire (VVIQ) is used to evaluate the quality of an individual's ability to produce a mental image, and is often used to identify Aphantasia. The VVIQ has been demonstrated to be an accurate test of the ability to visualise an image.

This questionnaire provides self-report data, and invites the participant to visualise a series of scenarios which are verbally described in the questionnaire. The VVIQ consists of four sections each containing four scenarios on related stimuli. For example, section one asks you to picture faces, individuals rank how vivid the image is, from "no image at all, you only know that you are thinking of the object" (1 point) to "perfectly clear and lively as real seeing" (5 points). The questionnaire uses a Likert scale to score individuals out of 80, with 80 equating to Hyperphantasia (perfect mental imagery) and 20 or lower equating to Aphantasia.

Neurological Bases
There is research suggesting that aphantasia is due to a lack of activation within neural pathways associated with visual abilities.

An fMRI study conducted by Fulford et al. investigated the variation in activation of different brain areas associated with mental imagery. The study looked at the differences between neural activation in participants with low and high visual abilities, the visual abilities of the individuals were assessed using the VVIQ. An fMRI was conducted on each participant while they were asked to recreate mental images. The results found that participants with low levels of visual abilities had a widespread activation among brain regions when visualizing images, whereas those with high levels of visual abilities had more specific activation within visual pathways.

Psychological Bases
Vito and Bartolomeo (2015) suggested that Aphantasia might have a psychological aspect, and could be an outcome of depressive states, or dissociative disorders. Furthermore, Zeman suggested that psychological causes are found in related disorders, such as synaesthesia and prosopagnosia.

Treatment/ Management
Individuals do not report being significantly impaired by Aphantasia, so there is no urgent need for treatment. Many individuals are unaware that their own conscious experience varies from others, meaning many individuals do not know they have Aphantasia until they hear of someone else's experience.

Image streaming is a method used to try to improve an individual's ability to create mental imagery, the process involves participants closing their eyes and trying to describe colours or shapes that they can see on their eyelids. This idea of shapes on someone's eyelid can be compared to looking into a bright light and focusing on the afterimage.

Metivier (2018) has also suggested using verbal description of memory, claiming that regular verbal description of non-visual memories can aid development of imaging abilities. Figueroa (2018) further described this process as imagining what they would see if they had mental visualisation abilities. Furthermore he states that this process allows individuals to become aware of the details which could be recreated within metal imagery.

Patient Mx
Zeman and his team were approached by MX in 2015, who reportedly had acquired Aphantasia. The team proceeded to test MX’s ability in visual imagery ability tests, and found that his visual abilities did not significantly vary from those of the control group. MX also displayed normal functioning on tests of visual, auditory, autobiographical and general memory. Furthermore, they conducted an fMRI and BOLD imaging test which showed that MX had the same brain region activation when viewing a face as seen in the control group. However, when asked to visualise a face, MX showed increased activation in areas that control working memory and executive functioning.

Patient AI
Patient AI was initially participating in a study which looked at Congenital Aphantasia, her test results were noteworthy because she performed to the same level as the control participants on visual imagery tests. Furthermore,  she had a higher score than the control group on a test of working memory. However, when asked to perform a task using spatial reasoning within the working memory her performance was impaired. It was hypothesized that her performance could be attributed to alternative non-visual strategies.

Although the case studies demonstrate that individuals with Aphantasia can have normative or higher levels of memory function, this is not representative of all individuals with aphantasia.

Related Disorders

 * Creative visualization
 * Engineering and the Mind's Eye
 * Synaesthesia
 * Prosopagnosia
 * Autobiographical memory
 * Auditory processing disorder
 * Dyssomnia
 * Aphasia