2.4 Cognitive & Neurological Screening

Level of Consciousness and Orientation

Level of consciousness (LOC) is the earliest and most sensitive indicator of neurological deterioration — a declining LOC appears before pupillary changes, motor deficits, or the late vital-sign changes of Cushing's triad. Document behavior, not labels, but know the classic continuum:

• Alert: awake, oriented, responds appropriately
• Lethargic: drowsy but arouses to voice, drifts off when unstimulated
• Obtunded: difficult to arouse, requires repeated or loud stimulation, confused when awake
• Stuporous: arouses only to vigorous/painful stimulation, minimal verbal response
• Comatose: no purposeful response to any stimulation

Always stimulate in escalating order: voice, then touch, then painful stimulus (trapezius squeeze, supraorbital pressure, sternal rub — used briefly and documented).

Orientation is assessed to person, place, time, and situation. Loss follows a predictable order — time first, then place, then person (person is preserved longest). Document specifically ('oriented to person and place, disoriented to time') rather than 'A&O x4,' because granularity reveals trends.

Glasgow Coma Scale

The Glasgow Coma Scale (GCS) standardizes LOC in three domains; the best response in each is scored:

Total ranges 3 (deep coma) to 15 (fully intact). Severity bands: 13-15 mild, 9-12 moderate, ≤8 severe — and the airway rule every exam loves: 'less than 8, intubate' (a GCS ≤8 generally cannot protect the airway). Decorticate posturing (flexion, arms to the cord/core) indicates damage above the brainstem red nucleus; decerebrate posturing (extension) indicates brainstem-level injury and carries a worse prognosis. An intubated patient's verbal score is recorded as 'T' (e.g., E3 Vt M5).

Delirium vs Dementia vs Depression

The three D's are the highest-yield comparison in cognitive assessment:

Delirium is a medical emergency: hunt the cause — infection (UTI and pneumonia in older adults), hypoxia, hypoglycemia, drugs (anticholinergics, opioids, benzodiazepines), withdrawal, electrolyte derangement, urinary retention, fecal impaction.

Screening Tools: CAM, Mini-Cog, MMSE

The Confusion Assessment Method (CAM) is the validated bedside delirium screen. A positive CAM requires features 1 AND 2, plus either 3 or 4:

1. Acute onset and fluctuating course (did the change come on abruptly? does it wax and wane?)
2. Inattention (cannot follow a conversation, easily distracted, cannot recite digits or months backward)
3. Disorganized thinking (rambling, illogical, incoherent speech)
4. Altered level of consciousness (anything other than alert)

The Mini-Cog is the fast dementia screen: 3-item recall (repeat three unrelated words, recall after a distractor) plus the clock-drawing test (draw a clock showing a set time, e.g., 11:10). Scoring: 0 recalled words = positive screen; 1-2 words with an abnormal clock = positive; 1-2 words with a normal clock, or all 3 recalled = negative. It takes about 3 minutes and is minimally affected by education or language.

The Mini-Mental State Examination (MMSE) scores orientation, registration, attention/calculation (serial 7s), recall, and language out of 30 points; <24 generally indicates cognitive impairment, with 18-23 mild and 0-17 severe impairment commonly used as bands. Scores are skewed by education, language, hearing, and depression — interpret cautiously.

Pupillary Assessment

Assess pupils for size (normal 2-6 mm), shape, equality, and reaction — documented PERRLA (Pupils Equal, Round, Reactive to Light and Accommodation). Abnormal findings with high exam value:

• Pinpoint pupils: opioid toxicity, pontine hemorrhage, organophosphate poisoning
• Bilaterally dilated and fixed: severe anoxia, anticholinergic/atropine effect, or end-stage herniation
• Unilateral dilated, fixed ('blown') pupil: cranial nerve III compression from uncal herniation — usually on the side of the expanding lesion; this is a neurosurgical emergency
• Sluggish or unequal pupils (anisocoria): up to 20% of healthy people have mild physiologic anisocoria, but new anisocoria after head injury is herniation until proven otherwise

Developmental Age Considerations

In older adults, baseline sensory changes (presbycusis, presbyopia) contaminate cognitive testing — ensure glasses and hearing aids are in place before screening. Slower processing speed is normal aging; disorientation is not. Distinguish baseline function from acute change by interviewing family — the exam stresses that any acute change from baseline is delirium until proven otherwise. In younger adults, intact development and higher reserve can mask early decline, so trends and collateral history matter more than single scores. For all ages, serial assessment beats a single snapshot: chart the trend in GCS, orientation detail, and CAM features, and escalate any downward movement.

Brief Focal Deficit Screening

Alongside global cognitive screening, med-surg nurses screen for focal deficits that signal stroke or mass effect: facial symmetry (smile), pronator drift (arms extended, palms up, eyes closed — downward drift of one arm indicates contralateral motor weakness), grip strength equality, and speech (slurring vs word-finding difficulty). The public mnemonic FAST (Face drooping, Arm weakness, Speech difficulty, Time to call) applies at the bedside too — any new focal finding is a stroke alert until proven otherwise, because thrombolytic eligibility is time-limited from last known well.