Lateropulsion in Right-Sided Stroke: Brain Anatomical Correlates of Severity and Duration.

BACKGROUND AND PURPOSE: Lateropulsion (LP) is a profound disorder of postural control that has a significant impact on neurorehabilitation. Knowledge of relevant brain areas could guide decisions on appropriate intervention methods. Although LP severity and duration are highly variable in individuals with LP, imaging studies on LP have not sufficiently considered these aspects. The aim of this study was to investigate the lesion location in individuals after stroke and the correlation with LP duration and severity. METHODS: A retrospective case-control study using voxel lesion symptom mapping (VLSM) in 74 individuals with right-sided brain lesion (49 with and 25 without LP) was performed to analyze the correlation between lesion location and LP severity. Duration was investigated in a subsample of 22 individuals with LP. LP was diagnosed by means of the Scale for Contraversive Pushing. RESULTS: Individuals with LP showed significantly larger lesion sizes compared with the individuals with no LP. VLSM analysis of LP severity did not reveal statistically significant results. VLSM analysis showed a statistically significant association with longer LP duration for the inferior frontal gyrus, the hippocampus, the inferior parietal gyrus, the supramarginal gyrus, the angular gyrus, the temporal cortex, the sagittal stratum, and the superior longitudinal fasciculus. DISCUSSION AND CONCLUSION: LP-relevant areas are located in the multisensory network. Areas of the frontoparietal network, which are related to spatial cognition, memory, and attention, were found to be relevant for duration and severity. The findings, especially those regarding duration involving the middle temporal cortex, could explain the better intervention outcomes for methods based more on implicit than on explicit knowledge of verticality.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A433 ).

A Prospective Analysis of Lesion-Symptom Relationships in Acute Vestibular and Ocular Motor Stroke.

Background: Diagnosing stroke as a cause of acute vertigo, dizziness, or double vision remains a challenge, because symptom characteristics can be variable. The purpose of this study was to prospectively investigate lesion-symptom relationships in patients with acute vestibular or ocular motor stroke. Methods: Three hundred and fifty one patients with acute and isolated vestibular or ocular motor symptoms of unclear etiology were enrolled in the EMVERT lesion trial. Symptom quality was assessed by the chief complaint (vertigo, dizziness, double vision), symptom intensity by the visual analog scale, functional impairment by EQ-5D-5L, and symptom duration by daily rating. Acute vestibular and ocular motor signs were registered by videooculography. A standardized MRI (DWI-/FLAIR-/T2-/T2*-/3D-T1-weighted sequences) was recorded within 7 days of symptom onset. MRIs with DWI lesions were further processed for voxel-based lesion-symptom mapping (VLSM). Results: In 47 patients, MRI depicted an acute unilateral stroke (13.4%). The chief complaints were dizziness (42.5%), vertigo (40.4%) and double vision (17.0%). Lesions in patients with vertigo or dizziness showed a large overlap in the cerebellar hemisphere. VLSM indicated that strokes in the medial cerebellar layers 7b, 8, 9 were associated with vertigo, strokes in the lateral cerebellar layer 8, crus 1, 2 with dizziness, and pontomesencephalic strokes with double vision. Symptom intensity and duration varied largely between patients. Higher symptom intensity and longer duration were associated with medial cerebellar lesions. Hemispheric lesions of the cortex were rare and presented with milder symptoms of shorter duration. Conclusions: Prospective evaluation of patients with acute vestibular or ocular motor stroke revealed that symptom quality, intensity and duration were not suited to differentiating peripheral from central etiologies. Lesions in the lateral cerebellum, thalamus, or cortex presented with unspecific, mild and transient symptoms prone to being misdiagnosed.

Visual Timing of Structured Dance Movements Resembles Auditory Rhythm Perception.

Temporal mechanisms for processing auditory musical rhythms are well established, in which a perceived beat is beneficial for timing purposes. It is yet unknown whether such beat-based timing would also underlie visual perception of temporally structured, ecological stimuli connected to music: dance. In this study, we investigated whether observers extracted a visual beat when watching dance movements to assist visual timing of these movements. Participants watched silent videos of dance sequences and reproduced the movement duration by mental recall. We found better visual timing for limb movements with regular patterns in the trajectories than without, similar to the beat advantage for auditory rhythms. When movements involved both the arms and the legs, the benefit of a visual beat relied only on the latter. The beat-based advantage persisted despite auditory interferences that were temporally incongruent with the visual beat, arguing for the visual nature of these mechanisms. Our results suggest that visual timing principles for dance parallel their auditory counterparts for music, which may be based on common sensorimotor coupling. These processes likely yield multimodal rhythm representations in the scenario of music and dance.