| work Baa BC Clinical Opinion (continued)

Worker last name First name Middle initial | WorkSafeBC claim number
HOLAND MARK 42647461

January 30, 2026 ER report from Royal Columbian Hospital: The worker was seen for bilateral ear pain
and reported acoustic trauma from noise exposure to the computer fans at work. He also complained
about intermittent tinnitus and migraine. The physician noted that the ear examination was normal. The
physician discussed the case with Dr. Zahabi, ENT, and Dr. Zahabi does not think the symptoms are ear,
nose, and throat of origin given the normal hearing test results and normal ear exam. Dr. Zahabi
suspected that the work environment might have triggered the worker’s migraine headaches. ENT and
Neurology did not think outpatient follow up was warranted at the time.

February 27, 2026 ER report from St. Paul’s Hospital: The worker was seen for pain in his left ear,
migraines, and inability to sleep. The worker noted that he has a history of sensitivity to low level noises.
He also reports that he was seen by several physicians, who confirmed that the external canal and TM
looked unremarkable. His recent audiology assessment also showed essentially normal hearing. The
worker was referred to an outpatient ENT clinic for his ear pain.

March 3, 2026 ER report from Royal Columbian Hospital: The worker requested an ENT assessment. He
was told to follow up with the ENT clinic that he has been referred to at St. Paul’s Hospital.

March 5, 2026 ER report from Royal Columbian Hospital: The worker was seen again at the emergency
department for ear pain. He believed the noise exposure caused him to lose his hearing and that this
“impacts his vagal nerve and causes him to have seizures.” The physician reviewed footage of the worker
sleeping that he provided and did not see any evidence of tonic clonic movements.

Regarding the worker’s claim for an acoustic injury and his reported audiological symptoms:

Two mechanisms of injury within the audiological domain that can result in symptoms of hearing loss, tinnitus,
and/or ear pain from short term or a single incident of exposure to loud noise are acoustic trauma and acoustic
shock.

Acoustic trauma is defined as a sudden hearing loss resulting from a single exposure to an intense impulse
noise (Kirchner et al., 2012). The critical peak sound pressure level required to cause acoustic trauma is
approximately 130 dB SPL or greater (Dobie, 1995; Melnick et al., 1998; Price, 1986; Stewart, 2002). An
individual may perceive hearing loss and other symptoms such as tinnitus, hyperacusis, and ear pain,
immediately following exposure to high intensities; however, the symptoms are often temporary, with full
recovery over a period of days or weeks (Alberti, 1998; Axelsson & Hamernik, 1987; Milhinch, 2002).

Acoustic shock, on the other hand, is different from acoustic trauma in that it can be triggered by a sudden-onset,
unexpected, and intense sound that does not necessarily reach the critical sound intensity required to induce
acoustic trauma (McFerran & Baguley, 2007; Westcott, 2006). It is most-often diagnosed in call-centre operators
who use headsets and experience squeals from the headsets that are unexpected. Acoustic shock does not
seem to have a significant effect on hearing thresholds (Parker et al., 2014); however, it is associated with a
range of other symptoms (e.g., altered hearing; pain in the ear, head or neck; tinnitus; hyperacusis; aural
fullness; phonophobia; vertigo; fatigue; disorientation; anxiety; etc. [McFerran & Baguley, 2007; Milhinch, 2002;
Parker et al., 2014; Westcott, 2006]). Acoustic shock symptoms are expected to develop immediately or within a

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