The information provided here is not medical advice.
If you have any concerns about your health, please consult your physician.
How common is SDAM?
To date, the research literature has described five individuals with SDAM. However, we have been contacted by many others reporting this syndrome. We suspect that the prevalence of SDAM may be similar to other neurodevelopmental syndromes (e.g., synesthesia, developmental prosopagnosia), at 1-2% of the population. Those interested in participating in further research are encouraged to go here and complete an online survey.
Is SDAM a brain disease or illness?
Memory changes can occur for a variety of reasons, including brain disease and neurodegeneration or dementia. We have defined the SDAM syndrome as distinct from any pathological condition or disease state. The published cases with SDAM are healthy, with no evidence of brain disease.
What is the difference between SDAM and amnesia?
Amnesia refers to severe memory impairment, such as that associated with brain damage due to stroke, traumatic brain injury, dementia, or encephalitis in people whose memory was previously normal. Developmental amnesia may occur in association with brain damage sustained before or during birth. People with amnesia generally have poor learning or acquisition of new information on clinical memory tests. Their memory impairment affects the performance of daily life tasks.
SDAM is not amnesia. There is no identified brain disease in SDAM; performance on clinical diagnostic memory tests is not impaired. The impairment is confined to the subjective re-experiencing or reliving of personal past events, even though memory for the facts of those events is intact.
What are the brain changes associated with SDAM?
When comparing cases of SDAM to people without SDAM, we have found evidence of subtle differences in brain structure (in the right hippocampus) and function (i.e., the brain’s response to memory tasks). The effects that we observed are derived from research protocols. Future studies with larger samples will be required to confirm these differences, and to understand their origin.
Is SDAM something you are born with?
SDAM appears to be present throughout the lifespan, although the cases we have studied report realizing that their memory was different from that of others as teenagers or adults. A change in memory functioning associated with an event, such as trauma or brain injury would not be considered part of the syndrome.
My memory is not what it used to be. Do I have SDAM?
SDAM refers to the lifelong inability to mentally relive or reexperience personal past events. Memory changes due to aging, mild cognitive impairment, or dementia have a different origin and are not considered part of the SDAM syndrome.
Is SDAM associated with traumatic experiences?
Although trauma is associated with memory changes, there was no evidence of extraordinary psychological trauma in our cases.
Could SDAM be a manifestation of depression?
The memory syndrome of depression includes capture, rumination and executive impairments in autobiographical retrieval (Dalgleish et al, 2007) and a subtle but significant reduction in retrieval of episodic details (Söderlund et al., 2014). It does not entail an inability to re-experience past events.
If people with SDAM have no memory, how can they function in day-to-day life?
The impairment in SDAM is specific to episodic autobiographical memory or the vivid reliving of past events. Other forms of memory that do not require this type of "mental time travel" are preserved. These same learning and memory processes support normal acquisition of language, skills, and factual knowledge (such as the ability to remember the name of your school or the last four presidents).
People differ in their memory abilities. What makes SDAM special?
There are individual differences in memory abilities. What makes SDAM different is the degree of impairment. We are currently investigating whether SDAM reflects an extreme expression on the low end of normal variation or whether it should be considered a separate category on its own.
How important is visual imagery in SDAM?
People with SDAM report impaired visual imagery in memory, and our testing revealed visual memory impairments. People who lack the ability to form visual images (a syndrome known as Aphantasia) have reported a memory syndrome that appears similar to SDAM. We are currently investigating the role of visual imagery as opposed to other core processes, such as emotion, in individual differences in memory in general.
Are people with SDAM more or less susceptible to developing Alzheimer’s disease?
We have no data to support or rule out elevated risk of any disease in SDAM.
How can I get assessed for SDAM?
There is no formal assessment for SDAM – this is a topic of current research. If you would like to participate, please take our survey. You may be contacted about participating in further in-depth testing.
How can I improve my memory?
We have not researched interventions to improve memory in SDAM. Individuals with SDAM report use of diaries, photographs, and rehearsal to support their memory.
Where can I learn more about SDAM?
This website provides the most comprehensive resource on SDAM. Additional information on our work on individual differences and SDAM can be found here. Please check back for updates or send us an email here to be included on our mailing list.