Forgetting the Unforgettable: Transient Global Amnesia Part I: Pathophysiology and Etiology

Area of Science:

• Neurology
• Neuroscience
• Pathophysiology

Background:

• Transient global amnesia (TGA) is a clinical syndrome with sudden onset of temporary memory loss.
• Despite over 60 years of study, TGA remains poorly understood, with debated etiologies including vascular, epileptic, and migraine-related mechanisms.
• No definitive scientific proof supports current etiological theories for TGA.

Purpose of the Study:

• To review current knowledge on hippocampal anatomy, vascularization, and function.
• To discuss emerging theories on the etiology of TGA.
• To explore the pathophysiological cascade leading to hippocampal dysfunction during TGA attacks.

Main Methods:

• Literature review of TGA.
• Analysis of diffusion-weighted MRI findings showing CA1 hippocampal lesions.
• Hypothesizing the role of CA1 neuron vulnerability to metabolic stress.

Main Results:

• Diffusion-weighted MRI has demonstrated lesions in the CA1 field of the hippocampus.
• This finding supports the hypothesis of selective CA1 neuron vulnerability to metabolic stress in TGA pathophysiology.

Conclusions:

• The hippocampus, particularly the CA1 field, is implicated in TGA.
• Metabolic stress and selective CA1 neuron vulnerability are proposed as key factors in TGA.
• Further research is needed to elucidate the precise etiology and pathophysiology of TGA.