Prevalence of Upper Extremity Distal Predominant Weakness Pattern in Chronic Stroke

TL;DR

This study found that distal upper extremity weakness is common in chronic subcortical stroke, especially when the lesion is exclusively subcortical, which has implications for prognosis and rehabilitation planning.

Contribution

It provides the first prevalence data comparing distal upper extremity weakness in exclusively subcortical versus other stroke locations in chronic stroke patients.

Findings

Distal predominant weakness occurs in 30.6% of exclusively subcortical strokes.

In non-subcortical strokes, the prevalence is 17.4%.

Distal weakness is the most common pattern overall in chronic stroke.

Abstract

Background: Hemiparesis after subcortical stroke is classically described as distal upper-extremity (UE) predominant, but prevalence data in chronic stroke is limited. Objective: Determine the prevalence of distal predominant UE weakness in exclusively subcortical chronic stroke versus other stroke distributions, characterize cohort differences, and describe UE weakness patterns in chronic stroke overall. Methods: Outpatient records were retrospectively reviewed to identify chronic stroke subjects. Lesion locations were classified from radiographic reports as exclusively subcortical or not (using a whole brain and supratentorial definition). UE weakness was categorized as distal predominant or not. Prevalence was compared with $\chi$-squared testing and odds ratios (OR). Results: 250 subjects were included (mean 861 days post-stroke). Using the whole-brain definition, distal predominant weakness occurred in 30.6% of exclusively subcortical versus 17.4% of non-exclusively subcortical strokes (OR 2.09, 95% CI 1.15-3.81; p=0.014). Using the supratentorial definition, distal predominant weakness occurred in 27.9% versus 17.9%, respectively (OR 2.16, 95% CI 1.17-3.96; p=0.012). Across all chronic strokes, 60% had no UE weakness; distal predominant weakness was the most common weakness pattern (23%), followed by uniform UE weakness (12%); proximal predominant weakness was rare (3%). Conclusions: Distal predominant UE weakness is more prevalent in chronic exclusively subcortical stroke than in non-subcortical stroke. These prevalence estimates may help predict long-term outcomes based on lesion location, support rehabilitation planning, and aid clinical lesion localization and research prioritization.