Outcomes Following Mild Traumatic Brain Injury

(TBI)

Michael J. LarsonJuly 13, 2006

Mild Traumatic Brain Injury

Duration LOC: None to 30 minutes

Duration Post-traumatic amnesia:

Minutes to 24 hours

Glasgow Coma Scale (GCS):

13 to 15

Appearance: Stunned, dazed, drowsy, headache, nausea, disoriented

Glasgow Coma Scale Motor Response

Obeys commandsLocalizing responses to pain

Generalized withdrawal to painFlexor posturing to pain

Extensor posturing to pain No motor response to pain

654321

Verbal ResponseOriented

Confused conversationInappropriate speech

Incomprehensible speechNo speech

54321

Eye Opening ResponseSpontaneous eye opening

Eye opening to speechEye opening to pain

No eye opening

4321

GCSMild TBI = 13 - 15

Moderate TBI

= 9 – 12

Severe TBI = 3 - 8

Epidemiology of Mild TBI

• Approximately 80% of all head injuries are mild– ~145 per 100,000 – ~400,000 new cases each year

• 2:1 male-to-female ratio• Age (bi-modal): 14 to 24 or 75+

years• Treatment costs > $1 billion yearly

see McAllister, 2005

Modality of Injury

• 1) Transportation accidents– MVA, motorcycle, boating

• 2) Falls• 3) Assaults/guns• 4) Sports and recreation

Individuals Most Likely

• Age, gender• Ethnicity: (controversial) higher in

minorities • with previous TBI• with lower SES• with substance abuse• with previous psychiatric diagnosis

From Kraus & Chu, 2005

Cognitive Function After Mild TBI

3

Cogni t ive

Leve l

Preinjury Functioning

PTAComa

INJURY

Retro-Grade

Amnesia Months

6 9 12

Mild TBI

Moderate TBI

Severe TBI

Ongoing Cognitive Problems

Brief PTA

PTAOngoing Cognitive Problems

Vanderploeg, 2006

Cognitive Sequelae

• Short-term (i.e., first week post)– Slowed processing speed– Poorer performance on tests of

attention– Decreased working memory and

verbal/visual memory performance

Bohnen et al., 1993; Dikmen, 1986; Gronwall, 1989; McAllister, 2005

Cognitive Sequelae

• Long-term – controversial– Several studies show no long-term

cognitive effects of mild TBI• Dikmen et al., 1986 and 1995• Levin et al., 1987• Meta-Analyses:

– Binder et al., 1997– Schretlen et al., 2003

Cognitive Sequelae

TAKE HOME MESSAGE:

• 90 to 95% of Mild TBI have full recovery after one year– Most asymptomatic after 3-to-6

months– Little-to-no residual effects– Neuropsych measures may not be

extremely sensitive

Cognitive Sequelae

• Cognitive profile of the 5 to 10% who don’t recover in a year?

“Miserable Minority”

• What are some of the main reasons these individuals do not fully recover?

• What is the base rate for litigation in the “miserable minority?”

• What is the estimated base rate for malingering in litigating patients?

Predictors of Poor Cognitive Outcome

• Abnormal MRI/CT scan findings• Depressed skull fracture• History of previous mild TBI• GCS of 13 rather than 14 or 15• History of psychiatric d/o• Litigation

Self-Expectation

mTBImTBI

Psychiatric Conditions

Personality Traits

Medical Conditions

Intelligence Level

Demographic Characteristics

Medical Iatrogenesis

Litigation Iatrogenesis

Acute Symptoms

Chronic Symptoms

Psychiatric Conditions

Personality Traits

Medical Conditions

Intelligence Level

Coping Abilities

Social Support

Coping Abilities

Adapted from Vanderploeg, 2006

Cognitive

Affective Somatic

Post-Concussive Syndrome

Cognitive Affective Somatic

Decreased: •Memory•Attention•Concentration

•Depression•Irritability•Anxiety

•Headache•Fatigue•Insomnia•Dizziness•Photophobia

Post-Concussive Syndrome

• Pattern and course generally follows cognitive dysfunction– At one month:

• 55% headache• 65% fatigue• 40% dizziness• 65% irritability

– At one year few to no symptoms

Post-Concussion Syndrome

• PCS sxs prevalent in general population and what people expect after mild TBI– Mittenberg et al., 1992– Lees-Haley & Brown, 1993

• PCS sxs correlate:– Poorly with neuropsych.– Highly with depression and anxiety

Self-Expectation

mTBImTBI

Psychiatric Conditions

Personality Traits

Medical Conditions

Intelligence Level

Demographic Characteristics

Medical Iatrogenesis

Litigation Iatrogenesis

Acute Symptoms

Chronic Symptoms

Psychiatric Conditions

Personality Traits

Medical Conditions

Intelligence Level

Coping Abilities

Social Support

Coping Abilities

Adapted from Vanderploeg, 2006

Brain Trauma

Risk of Psychiatric D/O

• Increased propensity toward:– Depression (20 to 30% of MTBI)– Anxiety (24 to 55%)– PTSD/Acute Stress D/O (3 to 48%)– Obsessive-compulsive disorder??

A Final Case

• We now know his expected outcome• He comes to us in litigation one-year

after the fight. He wants to sue the referee for not stopping the fight earlier. He complains of dizziness, fatigue, depression, and memory difficulties.

• What tests might you give a year-post to confirm brain injury?

• Differential diagnoses?

Conclusions

• Majority sxs. of mild TBI will resolve in less than 6 months

• Post-Concussive Syndrome is controversial• Stress-diathesis approach to symptoms

warranted• Litigation status and malingering may play

a large role in outcomes (David will discuss)

• Increased propensity to psychiatric D/Os