Differences in neuroanatomy and functional connectivity between motor subtypes of Parkinson's disease

Jin Hua Zheng; Wen Hua Sun; Jian Jun Ma; Zhi Dong Wang; Qing Qing Chang; Lin Rui Dong; Xiao Xue Shi; Ming Jian Li; Qi Gu; Si Yuan Chen; Dong Sheng Li

doi:10.3389/fnins.2022.905709

Differences in neuroanatomy and functional connectivity between motor subtypes of Parkinson's disease

Front Neurosci. 2022 Jul 22:16:905709. doi: 10.3389/fnins.2022.905709. eCollection 2022.

Authors

Jin Hua Zheng^{1

2

3}, Wen Hua Sun^{1

2}, Jian Jun Ma^{1

2

3}, Zhi Dong Wang^{1

2}, Qing Qing Chang^{1

2}, Lin Rui Dong^{1

2}, Xiao Xue Shi^{1

2}, Ming Jian Li^{1

3}, Qi Gu^{1

2

3}, Si Yuan Chen^{1

2

3}, Dong Sheng Li^{1

2

3}

Affiliations

¹ Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, China.
² Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, China.
³ Department of Neurology, People's Hospital of Henan University, Zhengzhou, China.

Abstract

Background: The "postural instability/gait difficulty" (PIGD) and "tremor-dominant" (TD) motor subtypes of Parkinson's disease (PD) differ in their clinical manifestations. The neurological basis of these differences is unclear.

Methods: We performed voxel-based morphometric analysis and measured amplitudes of low-frequency fluctuation (ALFF) on 87 PIGD patients and 51 TD patients. We complemented this neuroanatomical comparison with seed-to-voxel analysis to explore differences in functional connectivity.

Results: The PIGD group showed significantly smaller gray matter volume in the medial frontal gyrus (mainly on the right side) than the TD group. Across all patients, gray matter volume in the medial frontal gyrus correlated negatively with severity of PIGD symptoms after controlling for age (r = -0.250, p = 0.003), but this correlation was not observed in separate analyses of only PIGD or TD patients. The PIGD group showed greater functional connectivity of the right superior frontal gyrus with the left lingual gyrus, right lateral occipital cortex, and right lingual gyrus. ALFF did not differ significantly between the two groups.

Conclusion: Postural instability/gait difficulty may be associated with smaller gray matter volume in medial frontal gyrus than TD, as well as with greater functional connectivity between the right superior frontal gyrus and occipital cortex. These results may help explain the clinical differences between the two motor subtypes of PD.

Keywords: MRI; Parkinson’s disease; postural instability; tremor-dominant; voxel-based morphometry.