Is Transient Global Amnesia a Network Disease?

Park, Kang Min; Lee, Ki Young; Kim, Sung Eun

doi:10.1159/000496511

Cited by 20 publications

(9 citation statements)

References 31 publications

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“…Such findings are in agreement with neuropsychological studies demonstrating a selective disorder of episodic memory in TGA without impairment of other components of memory. 18,19 Indeed, as suggested by previous SPECT, PET, tract-based spatial statistics, and fMRI studies, 10,[12][13][14][20][21][22] the present study leads to the concept of TGA as a network disease.…”

Section: Discussionsupporting

confidence: 57%

Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia

Hodel¹,

Leclerc

Zuber

et al. 2020

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is a sudden onset of anterograde and retrograde amnesia. We aimed to assess differences in terms of cortical thickness and structural brain connectome between patients with TGA (at acute and delayed postrecovery stages) and matched controls. MATERIALS AND METHODS:We report on 18 consecutive patients with TGA who underwent 3T MR imaging, including DTI and MPRAGE sequences, at the acute (mean delay postonset: 44 hours) and delayed post-recovery (mean delay: 35 days) stages. Structural connectome was assessed in patients with TGA and in 18 age-and sex-matched controls by using probabilistic fibertracking and segmentation of 164 cortical/subcortical structures ("nodes"). Connectivity graphs were computed and global network metrics were calculated. Network-based statistical analysis (NBS) was applied to compare patients with TGA at each stage with controls. We also compared cortical thickness between patients with TGA and healthy controls.RESULTS: Global network metrics were not altered in patients with TGA. NBS-analysis showed structural connectome alterations in patients with TGA compared with controls, in core regions involving the limbic network, with 113 nodes and 114 connections (33 left intrahemispheric, 31 right intrahemispheric, and 50 interhemispheric connections) showing significantly decreased structural connectivity (P , .05 NBS corrected, t-values ranging from 3.03 to 8.73). Lower cortical thickness compared with controls was associated with these structural alterations in patients with TGA, involving the orbitofrontal, cingulate, and inferior temporal cortices. All the abnormalities were visible at both acute and delayed postrecovery stages.CONCLUSIONS: Our preliminary study suggests there are structural abnormalities of the limbic network in patients with TGA compared with controls, including decreased structural connectivity and cortical thickness. ABBREVIATIONS: TGA ¼ transient global amnesia; TOF-MRA ¼ time-of-flight MRA; VBM ¼ voxel-based morphometry; AUC ¼ area under the curve; FDR ¼ false discovery rate; NBS ¼ network-based statistical analysis

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Section: Discussionsupporting

confidence: 57%

Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia

Hodel¹,

Leclerc

Zuber

et al. 2020

AJNR Am J Neuroradiol

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“…Finally, several studies using diffusion tensor imaging (DTI) investigations found that many cerebral regions showed decreased connectivity in patients with TGA compared with healthy subjects, suggesting that in patients with this disease there would be a reorganization of the brain network hubs [ 64 , 100 , 101 ].…”

Section: Vulnerability To Hypoxia and Pathophysiology Of Memory Disor...mentioning

confidence: 99%

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

Sparaco

Pascarella

Muccio

et al. 2022

JCM

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Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of a temporary memory disorder with a profound anterograde amnesia and a variable impairment of the past memory. Since the first description, dating back over 60 years, several cases have beenreported in the literature. Nevertheless, TGA remains one of the most mysterious diseases in clinical neurology. The debate regarding the etiology of this disease has focused mainly on three different mechanisms: vascular (due to venous flow changes or focal arterial ischemia), epileptic, and migraine related. However, to date there is no scientific proof of any of these mechanisms. Furthermore, the demonstration by diffusion-weighted MRI of lesions in the CA1 field of the hippocampus cornu ammonis led us to hypothesize that the selective vulnerability of CA1 neurons to metabolic stress could play a role in the pathophysiology of TGA. In this review, we summarize current knowledge on the anatomy, vascularization and function of the hippocampus. Furthermore, we discuss the emerging theories on the etiology and the pathophysiological cascade leading to an impairment of hippocampal function during the attacks.

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“…Additionally, a DTI study has demonstrated the disrupted neuronal integrity in the cingulum fibers in patients with TGA [18]. Graph theory analysis using DTI MRI has been also applied to discover changes of structural connectivity in patients with TGA [19]. It has showed hubs reorganization, especially brain regions related with default-mode network, in TGA compared with healthy controls.…”

Section: Introductionmentioning

confidence: 99%

Glymphatic System Function in Patients with Transient Global Amnesia

Lee¹,

Park²,

Park³

et al. 2022

J. Integr. Neurosci.

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Background:The purpose of this study was to examine glymphatic system function in patients with transient global amnesia (TGA), as well as to conduct a recurrence analysis. Methods: We enrolled patients with TGA and healthy controls from our hospital retrospectively. The patients and healthy controls were all scanned with the same 3T scanner, which included diffusion tensor imaging (DTI). We investigated the function of the glymphatic system using DTI analysis along the perivascular space (DTI-ALPS). The ALPS index was compared between patients with TGA and healthy controls, as well as between patients who had recurrent TGA events and those who had only a single TGA event. Results: Seventy-two patients with TGA and 53 healthy controls were enrolled. Sixty-five patients with TGA had a single TGA event, while seven patients had recurrent TGA events. The ALPS index did not differ significantly between patients with TGA and healthy controls (1.665 vs. 1.618, p = 0.436). The ALPS index, on the other hand, varied significantly according to recurrence in patients with TGA. The ALPS index was significantly higher in patients with recurrent TGA events compared to those with a single event (1.928 vs. 1.636, p = 0.049). Conclusions: We investigated the glymphatic system function in patients with TGA compared to healthy controls for the first time using the DTI-ALPS method. We discovered that these groups did not differ in terms of glymphatic system function. However, glymphatic system function in patients with TGA may differ according to recurrence. Additional research is required to substantiate these findings.

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Is Transient Global Amnesia a Network Disease?

Cited by 20 publications

References 31 publications

Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia

Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia

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

Glymphatic System Function in Patients with Transient Global Amnesia

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