Validation of the Early Functional Abilities scale: An assessment of four dimensions in early recovery after traumatic brain injury
Ingrid Poulsen, Svend Kreiner, Aase W. Engberg
Department of Neurorehabilitation, Traumatic Brain Injury, Rigshospitalet, Kobenhavn, Denmark. E-mail: firstname.lastname@example.org
Objective: The Early Functional Abilities scale assesses the restoration of brain function after brain injury, based on 4 dimensions. The primary objective of this study was to evaluate the validity, objectivity, reliability and measurement precision of the Early Functional Abilities scale by Rasch model item analysis. A secondary objective was to examine the relationship between the Early Functional Abilities scale and the Functional Independence Measurement™, in order to establish the criterion validity of the Early Functional Abilities scale and to compare the sensitivity of measurements using the 2 instruments.
Methods: The Rasch analysis was based on the assessment of 408 adult patients at admission to sub-acute rehabilitation in Copenhagen, Denmark after traumatic brain injury.
Results: The Early Functional Abilities scale provides valid and objective measurement of vegetative (autonomic), facio-oral, sensorimotor and communicative/cognitive functions. Removal of one item from the sensorimotor scale confirmed unidimensionality for each of the 4 subscales, but not for the entire scale. The Early Functional Abilities subscales are sensitive to differences between patients in ranges in which the Functional Independence Measurement™ has a floor effect.
Conclusion: The Early Functional Abilities scale assesses the early recovery of important aspects of brain function after traumatic brain injury, but is not unidimensional. We recommend removal of the “standing” item and calculation of summary subscales for the separate dimensions.
In rehabilitation of patients with traumatic brain injury, there has been a need for valid scales measuring the early recovery because the recommended assessment scales; e.g. the FIM scale, is not able to measure a patient’s very early signs of recovery, such as a stable blood pressure, staying calm in a supine position, swallowing function, and communication.
In this study, we have examined the validity of the Early Functional Abilities (EFA) scale by item analysis of responses to EFA items from 408 patients in rehabilitation after traumatic brain injury. The EFA scale measures recovery after traumatic brain injury on four dimensions: vegetative, sensory-motor, facial-oral and communication-cognitive functions. After removal of one item from the scale, the analysis by Rasch models supports claims that the EFA subscales provide valid measures of functions related to early recovery in patients after traumatic brain injury. However, a total score summarizing responses to all EFA items is not recommended because the analysis shows that vegetative, sensory-motor, facial-oral and communication-cognitive functions are qualitatively different abilities. Replacing the four subscores with a total score may therefore hide differences among abilities that may be important to evaluate the rehabilitation of patients.