Functional Electrical Stimulation (FES) of the upper limb alleviates unilateral neglect: A case series analysis

Abstract

We report the results of a new form of therapy for unilateral spatial neglect. Functional electrical stimulation (FES) applied to the left forearm extensor muscles reduced the symptoms of severe left unilateral visual neglect in three patients, with the benefits being measurable at 6 months post-treatment. We suggest that FES activates a proprioceptive map within the right parietal lobe whose level of activation is otherwise diminished by the lesion. This both increases awareness of the contralesional side and stimulates functional interactions with the environment.

Keywords:

• Functional electrical stimulation
• Unilateral neglect
• Rehabilitation

We thank David Punt for assistance with the experimental design, Johan Hullemans for statistical advice and Glyn Humphreys for help with the manuscript. The second author gratefully acknowledges the support of the Stroke Association and the MRC.

Notes

1. A total of 27 patients showing signs of neglect were considered for inclusion in the study. Only four patients within this sample showed stability of performance during the baseline period (the others all showed a degree of recovery). These four were selected for inclusion because of the apparent intractability and severity of their neglect symptoms.

2. The gross function subscale assesses balance, gross mobility, ambulation and step climbing. For patients to achieve higher scores, they are required to walk without an aid, walk up and down four steps without a rail, and perform a functional task including walking, turning, and object retrieval.

3. For the Star Cancellation and Picture Naming Tasks the different phases of the experiment were compared to each other by ‘testing the difference between two bs’ (Howell, 1982), where ‘b’ refers to the gradient or incline of the slope. The difference is quoted as ‘t’. Note that if during one phase of the experiment there was no change in the subject's ability to cancel stars then the line on the graph will be flat. A comparison between the two phases is not possible and the b2 value only can be quoted.

4. Other areas which showed overlapping tactile and near-visual processing were found in the right central sulcus, the posterior superior temporal sulcus, inferior frontal gyrus and the left parietal operculum.