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Open Access Research article

Visual contrast sensitivity in patients with impairment of functional independence after stroke

Natanael Antonio dos Santos and Suellen Marinho Andrade*

Author Affiliations

Laboratório de Percepção, Neurociências e Comportamento, Departamento de Psicologia, Universidade Federal da Paraíba, João Pessoa, Brazil

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BMC Neurology 2012, 12:90  doi:10.1186/1471-2377-12-90

Published: 12 September 2012

Abstract

Background

Stroke has been considered a serious public health problem in many countries, accounting for complex disorders involving perception, such as visual, cognitive and functional deficits. The impact of stroke on the visual perception of individuals with impairments in functional independence was investigated.

Methods

We measured changes in functional independence and visual function in 40 patients with stroke (M = 52.3, SD = 0.65) and 10 controls (M = 52.5, SD = 0.66). The patients were divided into four subgroups following the Barthel Index (Group A: 20–35, serious dependence; Group B: 40–55, moderate dependence; Group C: 60–95, mild dependence; and Group D: 100 points, independence). Visual function was evaluated using the Contrast Sensitivity Function (CSF). The contrast threshold was measured using a temporal, two-alternative, forced-choice psychophysical method.

Results

The results show significant differences in CSF between healthy volunteers and patients with stroke (F (1.56) = 151.2, p < 0.001) for all frequencies (F (2.56) = 125.96, p < 0.001). The results also show that patients with low functional independence had lower contrast sensitivity than those with greater functional independence (F (3.56) = 344.82, p < 0.001).

Conclusions

An association exists between CSF and a worsening in the functional potential for performing daily living activities. Our results suggest that the CSF can be used as a diagnostic tool to analyze visual function associated with deficits in functional independence after stroke. These findings should be considered across the continuum of care for these patients.

Keywords:
Contrast sensitivity; Stroke; Functional independence; Spatial frequency