AIPG 2003 ENT Cahartz notch

Question. 70.
Carharts notch in audiogram is deepest frequency of:
1. 0.5KHz
2. 2 KHz.
3. 4 KHz.
4. 8 KHz.
Answer
2. 2 KHz.
Reference
Fundamentals of Ear, Nose, Throat and Head and Neck Surgery – S.K.De – 7th Edition Page 141
Diseases of Ear, Nose and Throat. – P.L.Dhingra - 2nd Edition Page 93 Figure 13.2
Quality
Reader
Status
Repeat
QTDF
Dhingra
Discussion
Otosclerosis is a disease of the bony labynth where there are few bone changes

Normal Bone	Otosclerosis
Normal :-)	Abnormal :-(
Dense	Spongy
Avascular	Vascular
Regular	Irregular

Epidemiology
• It is more common is females
• More common around puberty
• More common in whites (The only use of remembering these “American” Statistics is for your Entrance Exams!!)
Symptoms
• Hearing Loss
o Painless,
o Progessive
o Insidous Onset
o Bilateral
o Conductive type
• Paracuses Williss – the patient hears well in noisy surroundings
• Tinnitus
• Vertigo
• Monotonous Speech
Signs
• Tympanic Membrane is NORMAL in most of the cases (Remember that this is the most common finding and the Schwartz sign though classical is not seen in all cases)
• Schwartz Sign may be seen – It is a Reddish Blue or Flamingo Pink Tinge seen on the promontory through TM
• Cahartz notch is seen in Bone conduction curve. There is a dip in the conduction at various frequencies and the maximum dip occurring at the frequency of 2000 Hz or 2 Khz is called as Cahartz Notch
Treatment – See the discussion for the next question
Explanation
1. 0.5KHz is not Cahartz Notch
2. Cahartz notch is at 2 KHz.
3. In noice induced hearing loss there is a curve at 4 KHz.
4. 8 KHz is not Cahartz Notch.
Comments
Bone Conduction is normal in Otosclerosis except in the Cochlear Variant
Tips
The notch at 4 Khz seen in Noice Induced Hearing loss is called as “Boiler Maker’s Notch”