A 55 year old right handed man presented to the ear, nose, and throat outpatient clinic with tinnitus and reduced hearing in his right ear. Clinical examination was unremarkable. His pure tone audiogram showed an asymmetrical sensorineural hearing loss, worse on the right, with a decrease on that side at 4-6 kHz (fig 1
) typical of a noise induced hearing loss.1 He had been playing golf with a King Cobra LD titanium club three times a week for 18 months and commented that the noise of the club hitting the ball was "like a gun going off." It had become so unpleasant that he had been forced to discard the club.
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Magnetic resonance imaging of his internal acoustic meati showed no abnormality, and we deduced that his asymmetrical sensorineural hearing loss was attributable to the noise of the golf club. Other than regular golf, he had no history of prolonged occupational or recreational exposure to loud noises (such as shooting) or exposure to ototoxic substances to account for this noise induced loss.
Our internet search of reviews for the King Cobra LD club found some interesting comments:
- "Drives my mates crazy with that distinctive loud ‘BANG’ sound. Have never heard another club that makes so distinctive a sound. It can be heard all over the course, it is mad!!"
- "A very forgiving club . . . albeit the ‘unusual’ clanking sound."
- "I don’t mind the loud BANG as it sounds like the ball goes a really long way. It sounds like an aluminium baseball bat, so some may not like it."
- "This is not so much a ting but a sonic boom which resonates across the course!"
Diagnosis of noise damage
Guidelines exist to help diagnose noise induced hearing loss, setting out three requirements and four modifying factors that must be considered to formulate a firm diagnosis.1 Our patient’s audiogram met the requirements for a high frequency hearing impairment. His hearing was at least 10 dB worse at 4-6 kHz than at 1-2 kHz, and there was a downward notch of at least 20 dB in the 3-6 kHz range (fig 1
). The remaining requirement—continuous noise exposure of 100 dB (or 90 dB for susceptible individuals)—does not apply in this case as we are dealing with impact (50 µs) noise. The modifying factors were also consistent with noise induced impairment.
He had no previous history of noise exposure, and the tinnitus described was a characteristic of noise exposure. In addition, calculation of Robinson-Sutton’s equations2 confirmed that in a man of 55 years, age induced hearing loss (presbyacusis) could not account for the loss at 4-6 kHz in his right ear, and that it must have been due to noise exposure.
Noisy clubs
The coefficient of restitution (COR) of a golf club is a measure of the elasticity or efficiency of energy transfer between a golf ball and club head. The United States Golf Association, in conjunction with the Royal and Ancient, St Andrews, Scotland, stipulates that the upper limit of COR for a golf club in competition use is 0.83.3 This means that a club head striking a ball at 100 miles per hour (mph) will cause the ball to travel at 83 mph. Thinner faced titanium clubs, such as the King Cobra LD, have a greater COR and deform on impact more easily, the so called trampoline effect, not only propelling the ball further, but resulting in a louder noise. The King Cobra LD and Nike SQ both have CORs above 0.83, making them non-conforming for competitions.3
The experience of our patient prompted us to study the sound levels produced by different golf drivers. A professional golfer hit three two-piece golf balls with six thin faced titanium golf drivers and six standard thicker faced stainless steel golf drivers. We used a modular precision sound level meter (Brüel and Kjær) to record the levels of sound impulse (dB). The distance from the right ear of the golfer to the point of impact between the golf club and ball was 1.7 m. We therefore positioned the sound meter 1.7 m from the point of impact.
The thin faced titanium clubs all produced greater sound levels than the stainless steel clubs (fig 2). Interestingly, the club used by our patient (King Cobra LD) was not the loudest. Our results show that thin faced titanium drivers may produce sufficient sound to induce temporary, or even permanent, cochlear damage, in susceptible individuals. The study presents anecdotal evidence that caution should be exercised by golfers who play regularly with thin faced titanium drivers to avoid damage to their hearing.
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Cite this as: BMJ 2008;337:a2835
Contributors: MAB initiated the study, took sound level measurements, and swung a few golf clubs, JMW and JEF took sound level measurements, and PRP provided clinical care to the patient. MAB is the guarantor. Competing interests: None declared.
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กีฬาบางประเภทอาจมีการใช้เสียงดังอย่างเห็นได้ชัด เช่นการยิงปืน ซึ่งอาจทำให้เกิดหูหนวกจากการได้ยินเสียงดังมาก (Noise-induced Hearing Loss) แต่สำหรับกอล์ฟที่ดูเหมือนจะเงียบๆ แล้วก็อาจทำให้หูหนวกได้
มีรายงานจาก Norfolk and Norwich University Hospital พบผู้ป่วยที่การได้ยินผิดปกติ หลังจากการตีกอล์ฟ โดยผู้เคราะห์ร้ายคนนี้ไม่ได้ทำอย่างอื่นที่มีเสียงดังเลยนอกจากการหวดลูก กอล์ฟด้วยไม้กอล์ฟ King Cobra รุ่น LD ซึ่งได้รับการกล่าวขานว่าเสียงดังเวลาหวดลูก ผู้ป่วยรายดังกล่าวได้รับการวินิจฉัยว่าการสูญเสียการได้ยินนั้นเกิดจากการ ได้รับเสียงดัง
เนื่องจากความสงสัยในเสียงที่ดังนี้ ทำให้ทางทีมแพทย์ที่รักษาทดลองเอาไม้กอล์ฟชนิดต่างๆ มาตีลูกแล้ววัดระดับเสียงที่เกิดขึ้น ผลปรากฎว่าไม้กอล์ฟรุ่นดังกล่าวส่งเสียงดังถึงเกือบ 130 เดซิเบล เวลาหวดลูก (เทียบเท่ากับเครื่องบินเจ็ตที่อยู่ห่างจากคนฟัง 100 ฟุตเลยทีเดียว) นอกจากนี้ยังพบว่าไม้กอล์ฟอีกหลายรุ่นโดยเฉพาะที่ทำจากไทเทเนียมทำให้เกิด เสียงดังมาก
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