In a healthy adult with a mild traumatic brain injury (concussion), should I perform the Addenbrooke’s Cognitive Examination (ACE‑III), and when and how often should it be administered?

ACE-III is Not Recommended for Routine Concussion Assessment

The Addenbrooke's Cognitive Examination (ACE-III) should not be performed as part of routine concussion evaluation in the emergency department or acute care setting. The available evidence does not support its use for mild traumatic brain injury assessment, and current guidelines do not recommend any formal cognitive assessment tools for predicting intracranial injury or guiding acute management decisions 1, 2, 3.

Why ACE-III is Not Appropriate for Concussion

Lack of Evidence for Mild TBI

• The ACE-III was designed to detect cognitive impairment in neurodegenerative conditions and structural brain lesions, not acute concussion 4
• No studies have validated the ACE-III specifically for mild traumatic brain injury or demonstrated its ability to predict clinically meaningful outcomes in this population 1
• Research shows that detailed neurologic examinations, including careful mental status assessments, have not demonstrated value in predicting acute intracranial lesions on CT scan in mild TBI patients 1

Guidelines Do Not Support Cognitive Testing in Acute Setting

• The American College of Emergency Physicians found no good studies demonstrating that cognitive assessment predicts intracranial injury in the acute phase 1
• While the U.S. military uses the Military Acute Concussion Evaluation (MACE) tool, its ability to predict intracranial injury has not been studied 1
• Current evidence-based guidelines focus on clinical decision rules (New Orleans Criteria, Canadian CT Head Rule) rather than formal cognitive testing for acute management 1, 2

What You Should Do Instead

Acute Assessment Approach

• Use validated clinical decision rules to determine need for CT imaging: Glasgow Coma Scale score, presence of neurologic deficits, signs of basilar skull fracture, dangerous mechanism of injury, vomiting, posttraumatic amnesia, and anticoagulation status 1
• Perform focused neurologic examination looking for focal deficits, altered consciousness, or signs requiring immediate intervention 2, 3

Discharge Management

• Provide written and verbal instructions at 6th-7th grade reading level to both patient and caregiver about expected symptoms, red flags requiring immediate return, and activity recommendations 2, 3
• Begin sub-symptom threshold aerobic exercise immediately at 60-70% of maximum heart rate for 15-20 minutes daily, rather than strict rest 2, 3, 5
• Implement partial cognitive rest with screen time limited to 30-minute intervals, rather than complete cognitive avoidance 2, 5

When Cognitive Testing May Be Appropriate

• Consider referral for specialized neurocognitive testing if symptoms persist beyond 3 weeks or significantly worsen despite conservative management 2, 5
• Computerized cognitive testing (such as Cambridge Neuropsychological Test Automated Battery) has shown feasibility in detecting deficits in mTBI patients, but is not yet standard of care for acute assessment 6
• Formal neuropsychological evaluation may be indicated for patients developing post-concussion syndrome (symptoms persisting beyond 3 months) 2, 3, 5

Critical Pitfalls to Avoid

• Do not delay discharge or imaging decisions waiting for cognitive test results, as these do not predict need for neurosurgical intervention 1
• Do not prescribe strict bed rest or complete activity restriction beyond 48-72 hours, as this may prolong recovery 2, 5
• Do not discharge without clear red flag instructions: repeated vomiting, worsening headache, increasing confusion, focal neurologic deficits, abnormal behavior, increased sleepiness, or seizures 2, 5

Expected Recovery Timeline

• Most patients (80-85%) recover completely within 3 months 2, 3, 5
• Persistent symptoms beyond 3 months occur in 15-20% and constitute post-concussion syndrome requiring specialist referral 2, 3, 5
• Risk factors for prolonged recovery include female gender, age >40 years, prior concussion history, high initial symptom burden, and pre-existing mood disorders 2, 3, 5