Influence of the Number of Predicted Words on Text Input Speed in Participants With Cervical Spinal Cord Injury

Abstract

Objectives: To determine whether the number of words displayed in the word prediction software (WPS) list affects text input speed (TIS) in people with cervical spinal cord injury (SCI), and whether any influence is dependent on the level of the lesion.

Design: A cross-sectional trial.

Setting: A rehabilitation center.

Participants: Persons with cervical SCI (N=45). Lesion level was high (C4 and C5, American Spinal Injury Association [ASIA] grade A or B) for 15 participants (high-lesion group) and low (between C6 and C8, ASIA grade A or B) for 30 participants (low-lesion group).

Intervention: TIS was evaluated during four 10-minute copying tasks: (1) without WPS (Without); (2) with a display of 3 predicted words (3Words); (3) with a display of 6 predicted words (6Words); and (4) with a display of 8 predicted words (8Words).

Main outcome measures: During the 4 copying tasks, TIS was measured objectively (characters per minute, number of errors) and subjectively through subject report (fatigue, perception of speed, cognitive load, satisfaction).

Results: For participants with low-cervical SCI, TIS without WPS was faster than with WPS, regardless of the number of words displayed (P<.001). For participants with high-cervical SCI, the use of WPS did not influence TIS (P=.99). There was no influence of the number of words displayed in a word prediction list on TIS; however, perception of TIS differed according to lesion level.

Conclusions: For persons with low-cervical SCI, a small number of words should be displayed, or WPS should not be used at all. For persons with high-cervical SCI, a larger number of words displayed increases the comfort of use of WPS.

Keywords: Communication aids for disabled; Rehabilitation; Software; Spinal cord injuries.