The need for hemispheric separation in pairwise structural disconnection studies

Röhrig, Lisa; Rosenzopf, Hannah; Wöhrstein, Sofia; Karnath, Hans‐Otto

doi:10.1002/hbm.26445

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…Anatomical terms throughout the manuscript follow the atlas and its labels. For the frequentist GLMs, we adapted customized MATLAB scripts, previously used for similar purposes (Röhrig et al, 2023). Correction for multiple comparisons was based on maximum-statistics permutation.…”

Section: Discussionmentioning

confidence: 99%

Bayesian evidence for the neural dissociation between finger and hand imitation skills

Rosenzopf,

Röhrig,

Goldenberg

et al. 2024

Preprint

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Introduction: For limb apraxia ‒ a heterogeneous disorder of higher motor cognition following stroke ‒ an enduring debate has arisen regarding the existence of dissociating neural correlates for finger and hand gestures in the left hemisphere. We re-assessed this question asking whether previous attempts analysing pooled samples of patients with deficits in only one and patients with deficits in both imitation types might have led to systematically biased results. Methods: We conducted frequentist and Bayesian, voxelwise and regionwise lesion symptom mappings on a pooled sample (N=96) and subsamples containing only shared and only isolated hand and finger imitation deficits and respective controls. Results: Anatomical analyses on the isolated sample reinforced a cortical dissociation of finger deficits (located more anteriorly) and hand deficits (located more posteriorly). The presence of patients with shared deficits did indeed dilute associations that appeared stronger in the respective isolated samples. Also, brain regions truly associated with hand imitation deficits showed a positive bias for finger imitation deficits, when the sample contained patients with shared deficits. In addition, our frequentist parameters uncovered that some of our Bayesian evidence supported reverse associations (damage protecting from rather than increasing the deficit). Discussion: Joint analyses of patients with shared and isolated imitation deficits do indeed lead to biases, which may explain why some previous studies have failed to detect the actual neural dissociation between hand and finger imitation deficits.

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Section: Discussionmentioning

confidence: 99%

Bayesian evidence for the neural dissociation between finger and hand imitation skills

Rosenzopf,

Röhrig,

Goldenberg

et al. 2024

Preprint

Self Cite

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show abstract

“…Only 100 regions were included in the first step of analysis. A larger sample size might result in a better data distribution on both hemispheres which might in turn lead to the detection of further disconnection-outcome associations, particularly in the light of potentially more sensitive hemisphere specific analyses 57 . Third, the present cohort comprised a relatively small group of early subacute ischemic stroke patients.…”

Section: Discussionmentioning

confidence: 99%

Frontoparietal structural network disconnections correlate with outcome after a severe stroke

Frontzkowski,

Fehring,

Frey

et al. 2024

Preprint

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Structural disconnectome analyses have provided valuable insights into how a stroke lesion results in widespread network disturbances and how these relate to deficits, recovery patterns, and outcome. Previous analyses have primarily focused on patients with relatively mild to moderate deficits. However, outcomes vary among survivors of severe strokes, and the mechanisms of recovery remain poorly understood. This study assesses the association between lesion-induced network disconnection and outcome after severe stroke. Thirty-eight ischaemic stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Lesion information was integrated with normative connectome data to infer individual disconnectome profiles on a localized regional and region-to-region pathway level. Ordinal logistic regressions were computed to link disconnectome information to the modified Rankin Scale after 3-6 months. Disconnections of ipsilesional frontal, parietal and temporal cortical brain areas were significantly associated with a worse motor outcome after a severe stroke, adjusted for the initial deficit, lesion volume, and age. The analysis of the underlying pathways mediating this association revealed location specific results: For frontal, prefrontal and temporal brain areas, the association was primarily driven by relatively sparse intrahemispheric disconnections. In contrast, the ipsilesional primary motor cortex, the dorsal premotor cortex, and various parietal brain regions showed a remarkable involvement of either frontoparietal intrahemispheric or additionally interhemispheric disconnections. These results indicate that localized disconnection of multiple regions embedded in the structural frontoparietal network correlates with worse outcome after severe stroke. Specifically, primary motor and parietal cortices might gain a particular importance as they structurally link frontoparietal networks of both hemispheres. These data shed novel light on the significance of distinct brain networks for recovery after severe stroke.

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“…As a second step, we employed connectome-based lesion-symptom mapping (CLSM) to explore alterations at the network-level (Gleichgerrcht et al, 2017). We computed pairwise (region-toregion, connection-wise) analyses with custom scripts in MATLAB R2019a that were used similarly in a previous study (Röhrig et al, 2023). Hereby, we investigated whether damage to direct structural connections between specific brain regions are associated with the severity of acute post-stroke neglect.…”

Section: Pairwise Analysesmentioning

confidence: 99%

Structural disconnections caused by white matter hyperintensities in post-stroke spatial neglect

Röhrig,

Karnath

2024

Preprint

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White matter hyperintensities (WMH), a common feature of cerebral small vessel disease, affect a wide range of cognitive dysfunctions, including spatial neglect. The latter is a disorder of spatial attention and exploration typically after right hemisphere brain damage. To explore the impact of WMH on neglect-related structural disconnections, the present study investigated the indirectly quantified structural disconnectome induced by either stroke lesion alone, WMH alone, or their combination. Further, we compared different measures of structural disconnections - voxel-wise, pairwise, tract-wise, and parcel-wise - to identify neural correlates and predict acute neglect severity. We observed that WMH-derived disconnections alone were not associated to neglect behavior. However, when combined with disconnections derived from individual stroke lesions, pre-stroke WMH contributed to post-stroke neglect severity by affecting right frontal and subcortical substrates, like the middle frontal gyrus, basal ganglia, thalamus, and the fronto-pontine tract. Predictive modeling demonstrated that voxel-wise disconnection data outperformed other measures of structural disconnection, explaining 42% of the total variance. Compared to using stroke lesion anatomy, prediction performance can be improved by either estimating stroke-based structural disconnections or delineating the combined anatomy of stroke lesion and WMH. We conclude that pre-stroke alterations in the white matter microstructure due to WMH contribute to post-stroke deficits in spatial attention, likely by impairing the integrity of human attention networks.

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The need for hemispheric separation in pairwise structural disconnection studies

Cited by 6 publications

References 21 publications

Bayesian evidence for the neural dissociation between finger and hand imitation skills

Bayesian evidence for the neural dissociation between finger and hand imitation skills

Frontoparietal structural network disconnections correlate with outcome after a severe stroke

Structural disconnections caused by white matter hyperintensities in post-stroke spatial neglect

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