npj Parkinsons Dis: Morphology of the thalamus that predicts frozen gait in Parkinson's

Freezing gait (FOG), a debilitating symptom affecting many patients with Parkinson's disease (PD), is defined as "the brief, episodic absence or marked reduction of footsteps despite the intention to walk

Freezing gait (FOG), a debilitating symptom affecting many patients with Parkinson's disease (PD), is defined as "the brief, episodic absence or marked reduction of footsteps despite the intention to walk

Figure 1 Title map of the paper

Figure 1 Title map of the paperFigure 1 Title map of the paper

To date, various studies have investigated clinical risk factors for conversion to FOG

To date, various studies have investigated clinical risk factors for conversion to FOG

Due to the limited evidence, investigation of neural markers of conversion is warranted for additional predictive purposes and to help explain the elusive mechanisms that contribute to the pathogenesis of FOG

While FOG may mark temporal information-processing impairments in the cortical-basal ganglia-thalamo-cortical parallel circuit, these temporal events are challenging to induce and interpret, and thus have poor applicability as predictive markers

However, compensatory or adaptive structural changes at nodes in these circuits are more persistent and thus more readily captured as possible predictive markers of FOG in PD

A recent systematic review of cross-sectional surveys of structural alterations in patients with PD and FOG revealed extensive cortical and subcortical gray matter atrophy, and an association between FOG severity and atrophy, suggesting that gray matter morphology may be a useful marker of FOG onset and progression

In addition, subcortical structures are affected earlier when PD pathology of central or peripheral origin enters the brain, perhaps an early marker of FOG onset

Therefore, in this longitudinal study, Nicholas D'Cruz et al.

Based on previous cross-sectional work, the core hypothesis is that people with or about to develop FOG will experience local or global volume reductions in the brainstem, thalamus, and/or caudate compared with non-converters, which may act as a FOG transition neural markers

They then assessed the extent to which structural markers at the start of the study predicted conversion to FOG within two years and explored their behavioral associations and potential subnuclear volume and functional associations

Finally, these markers were initially validated using data from the Parkinson's Disease Progression Markers Initiative (PPMI) cohort

At the start of the study, they found that those with FOG (N = 12) and those who developed FOG during the study (converters) (N = 9), compared with those who did not convert (non-converters) (N = 36), Bilateral thalamic increases were shown

Figure 2 Schematic diagram of the morphological changes of the thalamus

Figure 2 Schematic diagram of the morphological changes of the thalamus

Longitudinal, converters (N = 7) also showed localized expansion of the left thalamus compared to non-converters (N = 36)

Longitudinal, converters (N = 7) also showed localized expansion of the left thalamus compared to non-converters (N = 36)

Exploratory analysis showed that regional thalamic gassing was associated with larger medial thalamic subnuclear volume and better cognitive performance
.
Resting-state analysis further revealed that switchers had stronger thalamo-cortical coupling with limbic and cognitive areas before switching, and significantly less coupling within two years
.

Finally, validation using the PPMI cohort showed a non-linear evolution of the FOG-specific thalamic local volume
.

Finally, validation using the PPMI cohort showed a non-linear evolution of the FOG-specific thalamic local volume
.
Validation using the PPMI cohort showed a non-linear evolution of the FOG-specific thalamic local volume
.

The significance of this study lies in the discovery that morphological changes in the thalamus may serve as markers of FOG, which may facilitate early intervention and improve mobility in PD patients
.

The significance of this study lies in the discovery that morphological changes in the thalamus may serve as markers of FOG, which may facilitate early intervention and improve mobility in PD patients
.

 

Original source:
D'Cruz N, Vervoort G, Chalavi S, Dijkstra BW, Gilat M, Nieuwboer A.
T halamic morphology predicts the onset of freezing of gait in Parkinson's disease.
npj Parkinsons Dis.
2021;7(1):20.
doi: 10.
1038/s41531-021-00163-0

Original source:
D'Cruz N, Vervoort G, Chalavi S, Dijkstra BW, Gilat M, Nieuwboer A.
T halamic morphology predicts the onset of freezing of gait in Parkinson's disease.
npj Parkinsons Dis.
2021;7(1):20.
doi:10.
1038/s41531-021-00163-0 halamic morphology predicts the onset of freezing of gait in Parkinson's disease.
npj Parkinsons Dis.


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