Evaluating Onset and Course in Neurological History

Introduction to Neurological History

The American Heart Association recommends establishing the precise time of symptom onset, as this directly determines treatment eligibility and guides diagnostic formulation, particularly for time-sensitive conditions like acute stroke where "last known well time" can mean the difference between receiving thrombolytic therapy or not 1, 2

For stroke patients, the time of onset is defined as when the patient was last at baseline or symptom-free, not when symptoms were first noticed, according to the American Heart Association 1
The "last known well time" determines eligibility for IV thrombolytic therapy (rtPA), which has a narrow therapeutic window, as recommended by the American Heart Association 2
If transient neurological symptoms completely resolved, the therapeutic clock resets and time of onset begins anew when new symptoms appear, as stated by the American Heart Association 1

Sudden or rapid onset typically indicates vascular events (stroke, hemorrhage), according to the American Stroke Association 4
Stepwise progression or waxing/waning symptoms suggest different pathophysiology than acute events, as noted by the American Stroke Association 4
Insidious, progressive onset over months to years points toward neurodegenerative conditions like Alzheimer's disease or cervical spondylotic myelopathy, as reported by the Alzheimer's Association 5, 6

Document how symptoms evolved over time in frequency, duration, and intensity, as recommended by the Alzheimer's Association 5, 7
The course typically falls into recognizable patterns, including progressive without plateau, which is a steady worsening without stable periods, as described by the Alzheimer's Association 5
Stepwise decline, characterized by new symptoms appearing in episodes with quiescent intervals between, is another common pattern, as noted by the American Stroke Association 4

The Alzheimer's Association recommends never accepting vague terminology like "memory loss" or "confusion" without clarification, and instead, encourage patients and informants to provide concrete examples of how symptoms manifest in daily life 5, 7
Quantify symptom intensity using validated scales, such as the NIH Stroke Scale for stroke, as recommended by the American Heart Association 2
Document functional limitations in activities of daily living (ADL) and instrumental ADL, as suggested by the Alzheimer's Association 8

Record individualized risk factors that inform both diagnosis and prognosis, including vascular risk factors, such as hypertension, hyperlipidemia, diabetes, smoking, and atrial fibrillation, as recommended by the American Heart Association 3
Other relevant factors, such as drug abuse, migraine, seizure, infection, trauma, and pregnancy, should also be documented, as noted by the American Heart Association 1

Headache, present in ~25% of stroke cases, and nausea/vomiting, particularly with posterior circulation strokes, are common associated symptoms, as reported by the American Stroke Association 4
Level of consciousness changes, motor symptoms, sensory changes, ataxia, and myoclonus are also important to characterize, as noted by the Alzheimer's Association 5

Structure your history to establish the overall level of impairment, the cognitive-behavioral syndrome, and likely causes and contributing factors, as recommended by the Alzheimer's Association 8
Use validated structured instruments to ensure comprehensive assessment, rather than relying solely on unstructured interview, as suggested by the Alzheimer's Association 5, 7
Document relevant negative findings that help exclude differential diagnoses, as recommended by the American Heart Association 3