IV. CLINICAL SIGNIFICANCE AND RELIABILITY OF THE CLINICAL OPINION IV.A Symptom Onset and Independent Audiometric Findings The worker's documented symptoms — unilateral (left) ear pain beginning January 23, 2026, aural fullness, worsening tinnitus, and sound sensitivity — began within days of the OMC1 exposure described in Part III, and were accompanied by a measured 10 dB threshold shift at 8 kHz in the left ear (Amplifon Surrey, January 30, 2026) compared to a September 2025 baseline taken four months earlier. The worker submits this represents new, measurable change attributable to the documented exposure, and that the Clinical Opinion does not adequately account for this shift, the acoustic telemetry described in Part III.B, or the spatial/directional analysis of the exposure. Evidence: Audiometric and Monitoring Records