Theme – Semiology – Part 2

Medical Semiology is the clinical discipline concerned with collection of signs and their interpretation as signals.

One of the most common sources of BIAS is performing examinations with a pre-conception of etiology or diagnosis – preconceptions blind observations and distort their interpretation.

Measurements should be routinely obtained, in particular occipito-frontal circumference (OFC). Measurements should be plotted on normative charts.

Symmetry should be routinely determined.

Examiners should focus as much on what is “normal” as on what is “abnormal” – the value of either category of signs is determined by the context of their interpretations (to sustain or challenge a hypothetical diagnosis).

Interpretations of signs should be avoided during data collection.

Examinations should be multiple and repeated at intervals. Likewise, interpretations and diagnoses should be revised with acquisition of new observations.