A-116 Neuropsychological Support for Use of Russell Posttraumatic Amnesia Classification of Traumatic Brain Injury

Objective To compare neurocognitive outcomes between 3 traumatic brain injury (TBI) groups (mild, moderate, severe) across 3 TBI classification systems: Glasgow Coma Scale (GCS) and Russell (mild <1 hour, moderate <24 hours and severe >24 hours) and the modified (mild <24 hours, moderate < one week and severe > one week) posttraumatic amnesia (PTA) systems. Method Private practice archival data were reviewed for ambulance/hospital documentation of lowest GCS and PTA duration. Exclusion criteria included ESL and failed tests of engagement. Tests included WAIS, WMS, WRAT, Halstead Reitan etc. Results There were 91 patients (16 mild, 30 moderate and 45 severe); 45 were male. Mean age and education was 30.9 and 12.6. Russell PTA classification yielded significant differences (t-tests) between mild and moderate TBI on 8 of 46 tests/measures and 13 differences in moderate versus severe and 24 differences in mild versus severe TBI. Differences were always severe > moderate > mild impairment, with most in psychomotor speed, memory, working memory and executive/frontal functions consistent with TBI. The modified PTA classification yielded 2 significant differences between mild and moderate, 6 differences between moderate and severe and 22 differences between mild and severe TBI. GCS yielded 0 differences between mild and moderate, 7 differences between moderate and severe and 14 differences between mild and severe TBI. The modified PTA and GCS reduced moderate TBI numbers and some differences were opposite expectations. Conclusions Russell PTA was superior to the modified PTA system and GCS in separation/discrimination (without reversals) and maintenance of moderate TBI as a substantive category.

Assessing Sleep Architecture With Polysomnography During Posttraumatic Amnesia After Traumatic Brain Injury: A Pilot Study

Background Early-onset sleep disturbance is common following moderate to severe traumatic brain injury (TBI) and often emerges while patients are in posttraumatic amnesia (PTA). However, sleep disruptions during this subacute recovery phase are not well-defined, and research often utilizes indirect measures (actigraphy) that quantify sleep based on activity. This study aims to examine sleep macro-architecture and sleep quality directly with ambulatory polysomnography (PSG) and measure endogenous salivary melatonin levels for patients experiencing PTA following moderate to severe TBI. Method Participants were recruited from an inpatient TBI rehabilitation unit. Nighttime PSG was administered at the patient’s bedside. Two saliva specimens were collected for melatonin testing on a separate evening (24:00 and 06:00 hours) using melatonin hormone profile test kits. Results Of 27 patients in whom PSG was recorded, the minimum required monitoring time occurred in n =17 (adherence: 63%) at a median of 37.0 days (quartile 1 [Q1] to quartile 3 [Q3]: 21.5-50.5) postinjury. Median non–rapid eye movement (NREM) and REM sleep proportions were similar to normal estimates. Slow-wave sleep was reduced and absent in 35.3% of patients. Sleep periods appeared fragmented, and median sleep efficiency was reduced (63.4%; Q1-Q3: 55.1-69.2). Median melatonin levels at both timepoints were outside the normal range of values specified for this test (from Australian Clinical Labs). Conclusion This study reports that ambulatory PSG and salivary melatonin assessment are feasible for patients experiencing PTA and offers new insight into the extent of sleep disturbance. Further research is necessary to understand associations between PTA and sleep disturbance.

Traumatic axonal injury on clinical MRI: association with the Glasgow Coma Scale score at scene of injury or at admission and prolonged posttraumatic amnesia

OBJECTIVEThe aim in this study was to investigate if MRI findings of traumatic axonal injury (TAI) after traumatic brain injury (TBI) are related to the admission Glasgow Coma Scale (GCS) score and prolonged duration of posttraumatic amnesia (PTA).METHODSA total of 490 patients with mild to severe TBI underwent brain MRI within 6 weeks of injury (mild TBI: median 2 days; moderate to severe TBI: median 8 days). The location of TAI lesions and measures of total TAI lesion burden (number and volume of lesions on FLAIR and diffusion-weighted imaging and number of lesions on T2*-weighted gradient echo or susceptibility-weighted imaging) were quantified in a blinded manner for clinical information. The volume of contusions on FLAIR was likewise recorded. Associations between GCS score and the location and burden of TAI lesions were examined with multiple linear regression, adjusted for age, Marshall CT score (which includes compression of basal cisterns, midline shift, and mass lesions), and alcohol intoxication. The predictive value of TAI lesion location and burden for duration of PTA > 28 days was analyzed with multiple logistic regression, adjusted for age and Marshall CT score. Complete-case analyses of patients with TAI were used for the regression analyses of GCS scores (n = 268) and PTA (n = 252).RESULTSTAI lesions were observed in 58% of patients: in 7% of mild, 69% of moderate, and 93% of severe TBI cases. The TAI lesion location associated with the lowest GCS scores were bilateral lesions in the brainstem (mean difference in GCS score −2.5), followed by lesions bilaterally in the thalamus, unilaterally in the brainstem, and lesions in the splenium. The volume of TAI on FLAIR was the measure of total lesion burden most strongly associated with the GCS score. Bilateral TAI lesions in the thalamus had the largest predictive value for PTA > 28 days (OR 16.2, 95% CI 3.9–87.4). Of the measures of total TAI lesion burden, the FLAIR volume of TAI predicted PTA > 28 days the best.CONCLUSIONSBilateral TAI lesions in the brainstem and thalamus, as well as the total volume of TAI lesions on FLAIR, had the strongest association with the GCS score and prolonged PTA. The current study proposes a first step toward a modified classification of TAI, with grades ranked according to their relation to these two measures of clinical TBI severity.