Characterising factors underlying praxis deficits in chronic left hemisphere stroke patients

Rounis, Elisabeth; Halai, Ajay D.; Pizzamiglio, Gloria; Ralph, Matthew A. Lambon

doi:10.1016/j.cortex.2021.04.019

Cited by 9 publications

(3 citation statements)

References 145 publications

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“…103,132 More recent studies have used PCA to described apraxic deficits observed in patients. 105,134 In a preliminary study, 40 chronic stroke patients tested on 8 apraxia tasks, identified 2 core components underlying apraxia. 134 These involved action selection and semantic control.…”

Section: Challenges and Emerging Work Diagnosismentioning

confidence: 99%

“…105,134 In a preliminary study, 40 chronic stroke patients tested on 8 apraxia tasks, identified 2 core components underlying apraxia. 134 These involved action selection and semantic control. The former was associated with lesions in the second branch of the superior longitudinal fasciculus, whereas the latter was associated with lesions within the ventral stream.…”

Section: Challenges and Emerging Workmentioning

confidence: 99%

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Limb Apraxias: The Influence of Higher Order Perceptual and Semantic Deficits in Motor Recovery After Stroke

Rounis

Binkofski

2023

Stroke

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Stroke is a leading cause of disability worldwide. Limb apraxia is a group of higher order motor disorders associated with greater disability and dependence after stroke. Original neuropsychology studies distinguished separate brain pathways involved in perception and action, known as the dual stream hypothesis. This framework has allowed a better understanding of the deficits identified in Limb Apraxia. In this review, we propose a hierarchical organization of this disorder, in which a distinction can be made between several visuomotor pathways that lead to purposeful actions. Based on this, executive apraxias (such as limb kinetic apraxia) cause deficits in executing fine motor hand skills, and intermediate apraxias (such as optic ataxia and tactile apraxia) cause deficits in reaching to grasp and manipulating objects in space. These disorders usually affect the contralesional limb. A further set of disorders collectively known as limb apraxias include deficits in gesture imitation, pantomime, gesture recognition, and object use. These deficits are due to deficits in integrating perceptual and semantic information to generate complex movements. Limb apraxias are usually caused by left-hemisphere lesions in right-handed stroke patients, affecting both limbs. The anterior- to posterior-axis of brain areas are disrupted depending on the increasing involvement of perceptual and semantic processes with each condition. Lower-level executive apraxias are linked to lesions in the frontal lobe and the basal ganglia, while intermediate apraxias are linked to lesions in dorso-dorsal subdivisions of the dorsal fronto-parietal networks. Limb apraxias can be caused by lesions in both dorsal and ventral subdivisions including the ventro-dorsal stream and a third visuomotor pathway, involved in body schema and social cognition. Rehabilitation of these disorders with behavioral therapies has aimed to either restore perceptuo-semantic deficits or compensate to overcome these deficits. Further studies are required to better stratify patients, using modern neurophysiology and neuroimaging techniques, to provide targeted and personalized therapies for these disorders in the future.

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Section: Challenges and Emerging Work Diagnosismentioning

confidence: 99%

Section: Challenges and Emerging Workmentioning

confidence: 99%

Limb Apraxias: The Influence of Higher Order Perceptual and Semantic Deficits in Motor Recovery After Stroke

Rounis

Binkofski

2023

Stroke

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“…To address this, a promising approach involves employing data-driven techniques like principal component analyses to unveil underlying, latent, patterns (Lambon Ralph et al, 2003, Butler et al, 2014. Notably, a prior study delved into apraxic de cits using principal component analyses, focusing on a set of eight apraxia tasks (Rounis et al, 2021). This analysis unveiled three core components that contributes to the disorder, encompassing aspects like posture selection, semantic control and sequencing de cits.…”

Section: Discussionmentioning

confidence: 99%

A preliminary study of white matter disconnections underlying deficits in limb apraxia

Rounis,

Thompson,

Pacella

et al. 2023

Preprint

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Limb apraxia is an acquired higher-order motor disorder affecting skilful actions, often observed following a stroke. It is assessed on tasks involving gesture production, recognition, imitation, object use, and multi-object sequencing. A two-system model for the organisation of action has been hypothesised based on errors patients make on these tasks. This distinguishes between deficits conceptualising actions mediated by an ‘indirect’ route to action, and deficits in implementing skilful actions, mediated via a ‘direct’ route. We tested 29 stroke patients with left hemisphere lesions on comprehensive apraxic tasks provided by the Birmingham Cognitive Screening. We employed white matter disconnection mapping, derived from patients’ structural T1 lesions and a diffusion-weighted dataset composed of 176 healthy participants, acquired with 7 T MRI scans from the human connectome project (HCP). Our analysis revealed that deficits in meaningless gesture imitation were associated with significant disconnection of the left and right occipital lobes via the splenium of the corpus callosum. This finding highlights a possible role of the right hemisphere in mediating ‘direct’ pathway- visuomotor deficits associated with apraxia. Though we did not identify a significant difference in tasks pertaining to an ‘indirect’ pathway in apraxia, there was a trend toward disconnection of the left fornix in gesture production tasks. Our results suggest separable disconnections associated with perceptual ‘direct’ and, possibly, more conceptual (memory-related) ‘indirect’ pathways. Further research with larger patient cohorts is needed to confirm and expand upon these findings, enhancing our understanding of the intricate neurobehavioural consequences of stroke, such as limb apraxia.

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A preliminary study of white matter disconnections underlying deficits in praxis in left hemisphere stroke patients

Rounis,

Thompson,

Scandola

et al. 2024

Brain Struct Funct

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Limb apraxia is a higher-order motor disorder often occurring post-stroke, which affects skilled actions. It is assessed through tasks involving gesture production or pantomime, recognition, meaningless gesture imitation, complex figure drawing, single and multi-object use. A two-system model for the organisation of actions hypothesizes distinct pathways mediating praxis deficits via conceptual, ‘indirect’, and perceptual ‘direct’ routes to action. Traditional lesion- symptom mapping techniques have failed to identify these distinct routes. We assessed 29 left hemisphere stroke patients to investigate white matter disconnections on deficits of praxis tasks from the Birmingham Cognitive Screening. White matter disconnection maps derived from patients’ structural T1 lesions were created using a diffusion-weighted healthy participant dataset acquired from the human connectome project (HCP). Initial group-level regression analyses revealed significant disconnection between occipital lobes via the splenium of the corpus callosum and involvement of the inferior longitudinal fasciculus in meaningless gesture imitation deficits. There was a trend of left fornix disconnection in gesture production deficits. Further, voxel-wise Bayesian Crawford single-case analyses performed on two patients with the most severe meaningless gesture imitation and meaningful gesture production deficits, respectively, confirmed distinct posterior interhemispheric disconnection, for the former, and disconnections between temporal and frontal areas via the fornix, rostrum of the corpus callosum and anterior cingulum, for the latter. Our results suggest distinct pathways associated with perceptual and conceptual deficits akin to ‘direct’ and ‘indirect’ action routes, with some patients displaying both. Larger studies are needed to validate and elaborate on these findings, advancing our understanding of limb apraxia.

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Characterising factors underlying praxis deficits in chronic left hemisphere stroke patients

Cited by 9 publications

References 145 publications

Limb Apraxias: The Influence of Higher Order Perceptual and Semantic Deficits in Motor Recovery After Stroke

Limb Apraxias: The Influence of Higher Order Perceptual and Semantic Deficits in Motor Recovery After Stroke

A preliminary study of white matter disconnections underlying deficits in limb apraxia

A preliminary study of white matter disconnections underlying deficits in praxis in left hemisphere stroke patients

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