The effects of post-traumatic amnesia on information processing following mild traumatic brain injury

Primary objective: The aim of this study was to determine whether a single measurement of level of PTA could distinguish patients more severely injured from those less so, by investigating the effect of PTA on psychometric test performance. Methods and procedures: Ninety patients with mTBI completed a word recall test, a spoken version of the Speed of Comprehension test and the Digit Symbol Substitution Test (Digit Symbol), within 24 hours of injury. These patients were divided into two groups, based on the presence (n=42) or absence (n=48) of PTA at the time of testing. PTA was measured with an eight-item orientation scale. Main outcomes and results: An independent groups design showed that patients with mTBI in PTA recalled fewer words after two presentations and after a delay and completed fewer symbols in 90 seconds on Digit Symbol than patients with mTBI not in PTA. Discriminant function analysis was applied to explore whether classifying severity of injury in terms of number of orientation questions answered would be useful. Conclusions: These results indicate that for individuals with mTBI in PTA, speed of information processing and verbal memory are impaired. A single brief administration of orientation questions may be sufficient to provide an index of severity of mTBI within the first 24 hours

Test-retest reliability and practice effects of a rapid screen of mild traumatic brain injury

Test-retest reliabilities and practice affects of measures from the Rapid Screen of Concussion (RSC), in addition to the Digit Symbol Substitution Test (Digit Symbol), were examined. Twenty five male participants were tested three times; each testing session scheduled a week apart. The test-retest reliability estimates for most measures were reasonably good, ranging from .79 to .97. An exception was the delayed word recall test, which has had a reliability estimate of .66 for the first retest, and .59 for the second retest. Practice effects were evident from Times 1 to 2 on the sentence comprehension and delayed recall subtests of the RSC, Digit Symbol and a composite score. There was also a practice effect of the same magnitude found from Time 2 to Time 3 on Digit Symbol, delayed recall and the composite score. Statistics on measures for both the first and second retest intervals, with associated practice affects, are presented to enable the calculation of reliable change indices (RCI). The RCI may be used to assess any improvement in cognitive functioning after mild Traumatic Brain Injury

Improved sensitivity of the rapid screen of mild traumatic brain injury

This study aimed to investigate the acute effects of mild traumatic brain injury (mTBI) in an emergency department sample. A total of 246 (186 male, 60 female) cases of mTBI and 102 (65 male and 37 female) cases of orthopedic injuries were tested within 24 hours of injury. Mild TBI patients performed more poorly on all subtests of the Rapid Screen of Concussion (RSC) and completed fewer symbols on Digit Symbol than did orthopedic controls. RSC scores predicted group membership better than chance, and Digit Symbol scores contributed significantly to predicting group membership over and above the contribution of the RSC, resulting in 70.4% sensitivity and 74% specificity for the extended protocol. The results of this study indicate that learning and memory, orientation, and speed of information processing are impaired immediately following mTBI. Furthermore, a brief battery of tests that include word recall, orientation, and the Digit Symbol Substitution Test could assess the severity of dysfunction following mTBI, and assist in clinical decision making regarding discharge, return to routine activities, and management of the effects of injury. © 2009 Psychology Press

The acute effects of mild traumatic brain injury on finger tapping with and without word repetition

This study aimed to investigate the acute effects of mild Traumatic Brain Injury (mTBI) on the performance of a finger tapping and word repetition dual task in order to determine working memory impairment in mTBI Sixty-four (50 male, 14 female) right-handed cases of mTBI and 26 (18 male and 8 female) right-handed cases of orthopaedic injuries were tested within 24 hours of injury. Patients with mTBI completed fewer correct taps in 10 seconds than patients with orthopaedic injuries, and female mTBI cases repeated fewer words. The size of the dual task decrement did not vary between groups. When added to a test battery including the Rapid Screen of Concussion (RSC; Comerford, Geffen, May, Medland T Geffen, 2002) and the Digit Symbol Substitution Test,finger tapping speed accounted for 1% of between groups variance and did not improve classification rates of male participants. While the addition of tapping rate did not improve the sensitivity and specificity of the RSC and DSST to mTBI in males, univariate analysis of motor performance in females indicated. that dual task performance might be diagnostic. An increase in female sample Size is warranted. These results confirm the view that there is a generalized slowing of processing ability following mTBI