Characterization of Traumatic Brain Injury Severity

Lisa A. Lombard

ISSUES IN CHARACTERIZATION OF TBI

• No universally accepted classification system exists for all stages of traumatic brain injury (TBI)

• Heterogeneity of characterization scales results in difficulty in interpretation and comparison of research studies and in prognostication for individual patients

• Challenges to the creation of a scale includes difficulty in capturing the wide range of severity of persons with TBI (from concussion to comatose), confounding factors on admission (intoxication, shock, etc.), other physical injuries that may limit function, and potential language deficits that may give inaccurate representation of orientation and command following.

CHARACTERIZATION OF INJURY

Glasgow Coma Scale

• Introduced by Teasdale and Jennett [1]; the most commonly used assessment for acute TBI (see Table 1.1)

• Assessment of three domains of eye opening, motor response, and verbal response

• Glasgow Coma Scale (GCS) 3 to 8 is defined to be severe TBI, 9 to 12 moderate, and 13 to 15 mild

• Limitations:

Unable to assess when administered after neuromuscular blockade, and verbal score cannot be obtained when the patient is intubated and is thus recorded as a 1T; this has led to outcome data where those with GCS 4 have a better outcome than with a GCS 3 [2]. These factors may lead to overestimation of brain injury severity and inability to acknowledge worsening neurologic deficit.

Many different providers may record the GCS in a trauma patient; studies cite inaccuracies in inter-rater reliability more than one-third of the time [3].

• As a single factor, the GCS has been shown to be only a modest predictor of rehabilitation outcome [4].

Rancho Los Amigos Levels of Cognitive Functioning

• Also known as the levels of cognitive functioning scale (LCFS), it was first outlined in 1972; it describes cognitive functioning after TBI on the basis of the interaction with environment [5] (Table 3.1).

TABLE 3.1 Rancho Los Amigos Cognitive Scale

I.	No response: unresponsive to any stimulus
II.	Generalized response: limited, inconsistent, and nonpurposeful responses—often to pain only
III.	Localized response: purposeful responses; may follow simple commands; may focus on presented object
IV.	Confused, agitated: heightened state of activity; confusion, disorientation; aggressive behavior; unable to perform self-care; unaware of present events; agitation appears as a result of internal confusion
V.	Confused, inappropriate: nonagitated; appears alert; responds to commands; distractible; does not concentrate on task; agitated responses to external stimuli; verbally inappropriate; does not learn new information
VI.	Confused, appropriate: good directed behavior, needs cuing; can relearn old skills as activities of daily living; serious memory problems, some awareness of self and others
VII.	Automatic, appropriate: appears generally oriented; frequently robot-like in daily routine; minimal or absent confusion; shallow recall; increased awareness of self and interaction in environment; lacks insight into condition; decreased judgment and problem solving; lacks realistic planning for the future
VIII.	Purposeful, appropriate: oriented and responds to the environment but abstract reasoning abilities are decreased with regard to premorbid levels

• Commonly used as a descriptive tool between professionals or for family education, or as a tracking tool for recovery; however, has no value in predicting outcome.

Mayo Portland Adaptability Inventory (MPAI-4) [6]

• Designed to be a post-hospital evaluation of the physical, cognitive, emotional, behavioral, and social issues experienced in persons with TBI

• Measurements in three subsets: ability (sensory, motor, and cognitive abilities); adjustment (mood, interpersonal interactions); and participation (social contacts, initiation, money management)

• May identify barriers to community reintegration

• Can be performed by professionals, caretakers, or persons with brain injury

ASSESSMENT OF OUTCOME: THE GLASGOW OUTCOME SCALE

• One of the earliest scales used to record outcomes from moderate or severe TBI (Table 3.2)

• Five categories, ranging from dead to good recovery. Some have concerns that the Glasgow Outcome Scale (GOS) oversimplifies patterns of recovery from TBI.

• The GOS-E (extended) increases the categories to eight, splitting each of the categories of severe disability, moderate disability, and good recovery into two each (upper and lower)

TABLE 3.2 Glasgow Outcome Scale

1.	Dead
2.	Vegetative state—unable to interact with environment; unresponsive
3.	Severe disability—able to follow commands; unable to live independently
4.	Moderate disability—able to live independently; unable to return to work or school
5.	Good recovery—able to return to work or school