ORIGINAL RESEARCH article

Front. Neurol.

Sec. Headache and Neurogenic Pain

Cognitive dysfunction and hippocampal metabolic alterations in patients with postherpetic neuralgia

  • Hangzhou Third People's Hospital,Zhejiang,China, Hangzhou, China

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Abstract

Abstract: Objectives: Chronic pain is closely related to cognitive function, and pain caused by different etiologies may impair diverse domains of cognition. However, the change of cognitive function and cellular metabolism in hippocampus in postherpetic neuralgia (PHN) patients have received little attention. This study aimed to investigate the cognitive function and cellular metabolism changes in bilateral hippocampus in patients with PHN. Methods: From July 2021 to December 2024, 41 PHN patients, 48 acute herpes zoster (HZ) patients and 43 controls were enrolled. 1H-magnetic resonance spectroscopy (1H-MRS) detected bilateral hippocampal metabolism. Cognitive function, pain intensity, depression and anxiety were assessed via Montreal Cognitive Assessment (MoCA), Numeric Rating Scale (NRS), Hamilton Depression Rating Scale (HAMD) and Hamilton Anxiety Rating Scale (HAMA), the correlation between clinical features and the cellular metabolism of bilateral hippocampal was analyzed. Results:Cognitive impairment occurred in 31.7% (13/41) of PHN patients, whose MoCA scores were significantly lower than HZ and control groups (P <0.05, P <0.01), mainly involving visualspatial executive function, attention and abstraction (all p<0.05). Binary logistic regression analysis found that duration of disease and NRS scores were independent risk factors for cognitive impairment in PHN patients (P<0.05). The Choline/Creatine (Cho/Cr) levels in the bilateral hippocampus of patients in the PHN group were significantly lower than those in the HZ and the control group (P<0.05, P<0.01), and the N-acetylaspartate/Creatine (NAA/Cr) levels in the bilateral hippocampus of patients in the PHN group were significantly lower than those in the control group (P<0.05). The duration of disease and NRS scores of PHN patients were negatively correlated with bilateral hippocampal Cho/Cr levels and MoCA scores (P<0.05, P<0.01), a positive correlation between HAMD/HAMA scores (P<0.01). Conclusions: PHN patients have a high incidence of cognitive impairment, mainly characterized by reduced visualspatial execution, attention and abstraction abilities, they also exhibit metabolic changes in bilateral hippocampus. Among them, PHN patients with long duration of disease and severe pain have more significant changes.

Summary

Keywords

Cellular metabolism, Chronic Pain, Cognitive Function, Hippocampus, Magnetic Resonance Spectroscopy, postherpetic neuralgia

Received

17 December 2025

Accepted

18 February 2026

Copyright

© 2026 Ni, Yuan, wang, Liu, Zhang and Yan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Yongxing Yan

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