PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB BACHELOR MEDICINE AND SURGERY (MBBS) UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

1. 1
Pathophysiology Of
Retrogradeamnesia
PROBLEM BASED LEARNING (PBL)
PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB
BACHELOR MEDICINE AND SURGERY (MBBS)
UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

2. • There are two types of amnesia: retrogradeamnesia (loss of
memories that were formed shortly before the injury)
and anterogradeamnesia (problems with creating new
memories after the injury has taken place).
• Both retrograde and anterograde forms may be referred to as
PTA, or the term may be used to refer only to anterograde
amnesia.

3. • Currently, the pathophysiological mechanisms which produce
post-traumatic amnesia are not completely known.
• The most common research strategy to clarify these
mechanisms is the examination of the impaired functional
capabilities of people with posttraumatic amnesia (PTA) after
a traumatic brain injury.

4. Neurological
mechanisms
Brain
imaging
studies
diaschisis

5. Neurological Mechanisms
• Research on the effect of emotional trauma on memory retention
and amnesic symptoms has shown that exposure to prolonged
levels of extreme stress has a direct effect on the hippocampus.
• Elevated stress levels can lead to an increase in the production of
enkephalins and corticosteroids.
• produce abnormal neural activity and disrupt long-term
potentiation (a neural mechanism associated with learning and
memory)

6. Diaschisis
• Diaschisis refers to the sudden dysfunction of portions of the brain
due to lesions in distant but connected neurons.
• Play an important role in PTA, more particularly in the declarative
memory impairments observed in patients experiencing an episode
of PTA.
• there is an increase in acetylcholine concentrations in the brain
after head injury.
• recent evidence implicates increased activity levels of choline
acetyltransferase, as a major cause.
• This increase in acetylcholine levels has also been tied to behavioral
suppression and unconsciousness.

7. Brain-Imaging studies
• Brain imaging techniques are useful for examining the changes in
the brain that occur as a result of damage.
• Metting et al. (2001) used CT-Scan to examine the
pathophyiological damage in patients currently experiencing an
episode of PTA, patients with resolved PTA, and a control group that
had not experienced PTA.
• Bloodflow to the occipital lobe, the caudate nucleus, and the grey
matter of the frontal lobe was significantly reduced in patients who
were scanned during the episode of PTA.
• No differences were seen between patients with resolved PTA and
the control group.