Clinical Tools
Observational Assessment Tools
Symptom checklists, standardised questionnaires, and clinician-administered scales form the backbone of current TBI diagnosis — but their reliance on self-report and subjective interpretation leaves a critical diagnostic gap that objective biomarkers are designed to fill.
What Are Observational Assessment Tools?
Observational assessment tools are structured instruments used by clinicians, trainers, and researchers to evaluate the presence and severity of TBI symptoms. They range from brief sideline screening tools — such as the Sport Concussion Assessment Tool (SCAT) and the Military Acute Concussion Evaluation (MACE) — to comprehensive neuropsychological batteries administered in clinical settings. These tools assess domains including orientation, memory, balance, coordination, and symptom burden.
While observational tools have been refined over decades and remain central to clinical practice, they share a fundamental limitation: they depend on the patient's ability and willingness to accurately report symptoms, and on the clinician's ability to interpret those reports in context. In high-pressure environments — on the sideline, in the field, or in the emergency department — this reliance on subjective assessment can contribute to under-detection, premature RTA, and long-term harm.
The Limits of Symptom-Based Diagnosis
~50%
of sport-related concussions may go unreported — largely due to under-reporting and the limitations of symptom-based screening tools
Normal
CT and MRI findings in the vast majority of mild TBI cases, leaving diagnosis entirely dependent on clinical and symptom assessment
Variable
sensitivity and specificity across observational tools — performance degrades significantly in non-clinical settings and high-pressure environments
No baseline
available for most patients — making it difficult to determine whether post-injury performance represents a meaningful change from the individual's norm
The Diagnostic Gap
Where Observational Tools Fall Short
The core limitation of observational tools is that they measure symptoms — not injury. A patient who minimises symptoms, lacks insight into their own cognitive impairment, or is motivated to return to play or duty can pass a symptom-based screen despite significant underlying neurological injury. Conversely, pre-existing conditions, anxiety, fatigue, or medication effects can produce symptom profiles that mimic concussion in the absence of brain injury.
Imaging studies — CT and MRI — are frequently normal following mTBI, providing no additional diagnostic certainty. The result is a diagnostic framework that is heavily dependent on clinical judgement, patient cooperation, and the experience of the assessor. GLIA's biomarker platform addresses this gap by providing an objective biological signal of neuronal injury that is independent of symptom reporting, imaging findings, or clinical assessment skill.
Common Assessment Tools
The Current Landscape of Observational Screening
SCAT6 (Sport Concussion Assessment Tool)
The most widely used sideline concussion assessment in sport. Combines symptom checklist, orientation questions, immediate memory, concentration, and balance testing. Requires a trained assessor and a pre-injury baseline for optimal interpretation.
MACE (Military Acute Concussion Evaluation)
The standard concussion screening tool for US military personnel. Assesses orientation, memory, and neurological symptoms following blast or impact exposure. Performance is compromised by operational pressure and the acute stress of combat environments.
GCS (Glasgow Coma Scale)
A rapid assessment of consciousness level used in emergency settings. Measures eye opening, verbal response, and motor response. Sensitive to severe TBI but poorly discriminating for mTBI, where GCS is typically normal.
PCSS (Post-Concussion Symptom Scale)
A 22-item self-report questionnaire assessing symptom severity across physical, cognitive, emotional, and sleep domains. Widely used in clinical follow-up but highly susceptible to response bias and symptom exaggeration or minimisation.
BESS (Balance Error Scoring System)
A standardised balance assessment used as part of the SCAT and independently. Evaluates six balance conditions, but its ability to identify concussion-related balance deficits diminishes substantially after the first 3–5 days post-injury.
King-Devick Test
A rapid number-naming assessment of eye movements, attention and processing speed. Sensitive to saccadic dysfunction following mTBI/concussion. Does not require a trained clinician but requires a pre-injury baseline and is not diagnostic in isolation.
Beyond Symptoms: The Case for Biomarker Diagnostics
Observational tools will remain part of the clinical toolkit — but the future of TBI diagnosis lies in objective biological measurement. GLIA's miRNA biomarker platform provides the missing signal that symptom-based tools cannot.