Rationale for the Development of ImPACT Version 4

Because a concussion is primarily a pathophysiological event rather than a structural event, and because traditional imaging tests are of little value in identifying the injury, there is a need to identify the neurocognitive changes associated with a concussion. ImPACT Version 4 is designed to provide relevant information regarding cognitive and clinical symptoms in individuals suspected of having sustained a Traumatic Brain Injury (TBI). This information, combined with other relevant clinical data and objective test information, can be used to help identify a concussion and manage recovery from an injury. This approach to clinical management of a concussed individual is a reliable and valid method for determining when an individual is sufficiently recovered from a concussion to return to daily activity.

The most common and effective way to use ImPACT Version 4 is to establish baseline performance in an individual prior to participation in an activity. A baseline test can either be supervised by a trained proctor following established standard administration procedures or taken remotely after the test taker reviews a set of instructions and watches a video of testing conditions and requirements (See Chapter 2 for a complete description). After a suspected concussion, an individual should be reevaluated by a trained healthcare professional. The individual’s performance on the post-injury evaluation is compared with his/her performance on the baseline evaluation. Any discrepancies in the results, along with other medical, behavioral, and psychological information should be used by the healthcare provider to make a determination about the individual’s concussion status and to serve as a guide for future treatment strategy.

Comparison of ImPACT to ImPACT Version 4

In developing the revision of ImPACT, special emphasis was placed on preserving much of what has made the test the most widely used tool for assessing and managing patients with a concussion. The primary changes were as follows:

1. New normative data by age and gender
   New normative data collected and stratified by age and gender. A complete description of the procedures used to collect the data and the description of the standardization sample can be found in Chapter 3.
2. Normative data for both mouse and trackpad administrations
   Earlier versions of ImPACT required the use of a computer mouse when performing the test. Over time, the computer mouse became less common and use of a trackpad became more common. New normative data is presented separately for users that use a trackpad and those that use a computer mouse.
3. Revised Invalidity Indicators
   Invalidity Indicator cut-offs have been recalculated using data from the new normative dataset.
4. Expansion of the normative age range from 12-59 to 12-80
   There is increasing evidence that TBI is the leading cause of hospitalization in individuals in the 60+ age range. As the population ages and people are working longer and staying active longer there is an increased risk of concussion in individuals 60 years and older. For that reason, we collected normative data that will enable ImPACT Version 4 to be used from ages 60 to 80 years 11 months.
5. An additional factor structure allowing for a two factor (speed and memory) interpretation of the test data
   Research has shown that in addition to the 4 composite scores historically been used to describe ImPACT test results, a Two-Factor Score can also provide a valid approach to interpreting the data.
6. New validity and reliability data
   New validity and reliability data were calculated as part of the renorming process. This includes data for the 60-80-year age range.
7. A revised clinical report design
   The clinical report has undergone redesign to make it simpler to use and explain. This includes the elimination of the Cognitive Efficiency Index which was omitted due to dearth of independent clinical and research support for this index.

All of these changes were made with the end user in mind so that ImPACT Version 4 remains easy to use and a valid tool to aid healthcare providers in evaluating and managing patients suspected of having a concussion.