Reference: Kampfl A, Schmutzhard E, Franz G, Pfausler B, Haring HP, Ulmer H, Felber S, Golaszewski S, Aichner F. Prediction of recovery from post-traumatic vegetative state with cerebral magnetic-resonance imaging. Lancet 351: 1763-67, 1998.

Structured settlement underwriting requires familiarity with the outcomes of severe traumatic injuries. One of the most difficult conditions to assess is Persistent Vegetative State (PVS). In adults, PVS lasting over 12 months almost uniformly predicts a life expectancy of 10 years, or generally much less. But for individuals who recover some function within the first 12 months, and especially within six months, the outlook may be significantly better(1). Early in the course of PVS, i.e., the first few months post-injury, it is particularly challenging to determine which individuals may recover vs. those destined for almost certain early death. The impact on underwriting decisions and liability is substantial. Thus, any aid in differentiating these cases would be of value. Many neurodiagnostic tests have been evaluated for this purpose, without any definitive evidence of usefulness to predict outcome.

This study prospectively followed 80 adult closed head injury (CHI) patients for 12 months who were consecutively admitted to a rehab center. MRI scans were performed on each patient in the subacute period, between six and eight weeks after injury, and each patient was considered to have PVS at the time of the MRI scan. Neurological outcome was determined by three separate neurologists at the time of the MRI and at two, three, six, nine and 12 months after injury to indicate some level of recovery--non-persistent vegetative state (NPVS)--or no recovery, i.e., persistent vegetative state (PVS). The two outcome groups did not differ significantly in age, sex, pupillary abnormalities, initial Glascow Coma Scale score (GCS), treatment methods (e.g., craniotomy for subdural hematoma), medical complications, or evidence of prehospital hypotensive or hypoxic episodes.

At one year, 42 patients remained in PVS and 38 showed some degree of recovery. Of the latter, recovery had started in 62% by three months and in 94% by six months. Two additional patients (6%) showed signs of recovery from six to 12 months after injury. Sixteen percent had a good recovery (all of whom began to recover within the first six months), 34% had severe disability, and 50% had moderate disability.

On MRI, 98% of the PVS patients had lesions in the corpus callosum compared to 24% of the non-PVS group. Dorsolateral upper brainstem injury occurred in 74% of the PVS vs. 26% of the non-PVS group and injury to the corona radiata was found in 57% of the PVS group vs. 26% of the non-PVS group. There was no statistically significant difference in the frequency or location of injuries to the lobar white-matter, thalamus, hippocampus, or in cortical contusions, cerebral atrophy, brainstem atrophy, or ventricular enlargement between the two groups. PVS patients had more cerebral lesions (mean 10.4) compared to non-PVS patients (mean 7.9).

Patients with lesions in the corpus callosum or dorsolateral brainstem on MRI had a 214-fold and seven-fold higher probability, respectively, of not recovering from PVS, using adjusted odds ratios for age, GCS score, pupillary abnormalities, and total number of lesions. PVS patients also had more lesions overall by MRI. The multiplicity of lesions at various locations is thought to help explain the variety of sensory, pyramidal, extrapyramidal, and cerebellar abnormalities typically seen in PVS. Although this study is limited by the relatively small number of patients, evidence on MRI of injury to the corpus callosum and/or dorsolateral brainstem may help to identify those individuals with a higher risk of early death after severe traumatic brain injury.

Structured settlement cases often contain very limited medical information, especially follow-up or current neurological data. Awareness of the potential impact on outcome of findings from MRI scans performed in the subacute hospital or rehab setting may be helpful in estimating life expectancy in cases of severe traumatic brain injury.

Reference:

1. The Multi-Society Task Force on PVS. Medical aspects of the persistent vegetative state (second of two parts). NEJM 1994; 330:1572-79.