Volumetric abnormalities of thalamic subnuclei in medication-overuse headache

DOI: https://doi.org/10.1186/s10194- 017- 0791- 5

Abstract-Summary The thalamus exerts a pivotal role in pain processing and cortical excitability con- trol and a previous voxel-based morphometry study confirmed increased volume in bilateral thalamus in medication-overuse headache (MOH).

The aim of this study is to investigate altered thalamic subnuclei volume in MOH compared with normal controls, and to evaluate the relationship of each thalamic subnuclei volume with the clinical variables.

The whole thalamus and each thalamic subnuclei presented increased volume

compared with NC (P < 0.05).

Increased gray matter volume in the whole thalamus and all the thalamus subnu-

clei may reflect central sensitization and higher-order of pain alteration in MOH.

Extended: Increased gray matter volume in DM, VPL and VPM may indicate

higher-order of pain are altered in MOH.

Background Previous primary headaches such as migraine are the most important risk factors for the development of MOH, 50%–70% MOH have co-occurrence of migraine in population- based studies [507, 527].

Many psychosocial and socioeconomic factors which are prevailed in patients

with chronic forms of headache are also associated with MOH.

A voxel-based morphometry (VBM) study identified increased gray matter vol-

ume in bilateral thalamus in MOH patients [516].

Although it was demonstrated that periaqueductal gray (PAG) volume gain [528] and altered intrinsic functional connectivity architecture [529] were confirmed in MOH patients in our previous study, however, it was not known that how the tha- lamic subfields volume changed in MOH up to now.

The main objective of the current study was to investigate the altered thalamic subnuclei volume in MOH compared with normal controls, and to further evaluate the relationship of each thalamic subnuclei volume with the clinical variables.

Methods Twenty-seven MOH patients were consecutively recruited from the headache cen- ter, Chinese PLA General Hospital.

3.5 Medication Overuse and Addiction

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The included criteria of MOH included as follows: (1) All patients with both, MOH and migraine; (2) The diagnosis of 8.2 MOH, 1.1 and 1.2 migraine based on the International Classification of Headache Disorders, third Edition (beta version) (ICHD-III beta); (3) Without migraine preventive medication in the past 3 months. Twenty-seven normal controls (NCs) were recruited, who should never have any primary headache disorders or other types of headache in the past year, and had the same exclusion criteria with MOH patients.

MRI scans were taken in the interictal stage at least three days after a migraine

attack for MOH patients.

The significance differences of whole thalamus and thalamic subnuclei volume were computed using analysis of covariance with the age and sex as covariates between MOH group and NC group.

Results The current study included 27 MOH patients (F/M = 20/7) and 27 normal controls (F/M = 19/8).

The age, sex and MMSE showed no significant difference between MOH and

NC (P > 0.05).

Discussion A previous study showed MOH patients have a greater risk of suffering from anxi- ety and depression than episodic migraine, and psychiatric disorders occurred sig- nificantly more often before the transformation from migraine into MOH than after [530].

Another follow-up study identified several risk factors for MOH among people with chronic headache, including increased Hospital Anxiety and Depression Scale score [512].

Consistent with the previous study [516], we found increased whole thalamus

volume bilaterally in the MOH.

Gray matter volume increase in the thalamus has also been found in chronic pain

conditions such as back pain [531] and chronic post-traumatic headache [532].

It suggests that increased gray matter volume in thalamus may relate to the

genetic background of patients with MOH.

We observed negative associations between HAMD scores and gray matter vol- ume in all the thalamus subnuclei in patients, suggesting that these structural changes may also be influenced by mood disturbances related to the disorder [533].

Conclusions These structural changes in the thalamus may also be influenced by mood distur- bances related to the MOH.

Acknowledgement A machine generated summary based on the work of Chen, Zhiye; Jia, Zhihua; Chen, Xiaoyan; Liu, Mengqi; Liu, Shuangfeng; Ma, Lin; Yu, Shengyuan. 2017 in The Journal of Headache and Pain.

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Volume gain of periaqueductal gray in medication-overuse headache