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Hearing evaluation :ear::skin-tone-2: (Anatomy of Hearing pathway (Parts…
Hearing evaluation :ear::skin-tone-2:
Anatomy of Hearing pathway
Parts of Ear
External
Middle
Internal
Cochlear
Hearing pathway
ความสามารถในการรับฟังเสียง
ค.ถี่ของเสียงที่มนุษย์รับฟังได้ = 20 - 20,000 Hz
Speech frequencies = 500 - 2,000 Hz
Levels of hearing
Normal hearing = ได้ยินเมื่อวัด pure tone แล้วได้ hearing threshold
< 25 dB
ในแต่ละ Freq.
Hearing loss = ,,----,, beyond 25 dB
Abnormal hearing
Symptoms :grapes:
Type of Hearing loss
Conductive hearing loss (CHL)
Sensori-neural heading loss (SNHL)
Mixed CHL & SNHL (1.+2.)
Central hearing loss
Functional hearing loss
Conductive hearing loss
Due to lesion @ External ear thru Middle ear
Characteristic features
Pt - speak soft voice as ได้ยินเสียงตัวเองชัด
Pt hear better in noisy areas (paracusis of Willis)
Tinnitus low pitched or buzzing (เสียงเหมือนลมพัด)
Mixed hearing loss
:duck: starts as
Conductive failure
➯ later deve a
Sensorineural
component
Otoscleorsis
:duck: starts as
Sensorineural
➯ then
Conductive defect
deve
Presbycusis with Middle ear infection
:duck:
Conductive & Sensorineural
starts พร้อมกัน
Severe head injury
Hearing loss fr Trauma usu happens in pterion area (ทัดดอกไม้)
2 types of Fx
Longitudinal Fx
of temporal bone
Found 80% of trauma
Hit from Left to Right
แรงกระทำน้อยกว่า
Transverse Fx
of temporal bone
Usu. severe force
Hit from Ant - Post way
Sensorineural hearing loss
Due to lesion @
Inner ear (sensory)
and/or auditory nerve (neural)
Characteristic features
Pt - speak
louder
voice as
ไม่
ได้ยินเสียงตัวเองชัด
Pt
difficult to hear
in noisy areas (paracusis of Willis)
Tinnitus
High
pitched
hissing
or
ringing
(เสียงเหมือนลมพัด)
Otologic findings are normal
Classification
:flags:
Cochlear
lesion (
inner
ear)
Speech discrimination
greatly reduced
if Moderate or Marked HL in speech frequencies
Recruitment
present
(recruitment = Abnormal :arrow_up: in loudness)
Threshold discomfort for loud sound
lowered
Retro
cochlear lesion
Speech discrimination พัง
(great different between hearing threshold lvl & speech discrimination score)
Recruitment
Threshold discomfort for loud sound
Central hearing loss
Due to lesion affects primarily CNS fr Auditory nuclei to the Cortex
Characteristic features
Hearing tests
do not indicate peripheral hearing impairment
Pure tone threshold ถือว่าดีเมื่อเทียบกับ ability of pt to discriminate what he hears
Difficulty
in interpreting complex info + Neurological findings
Hearing tests
TBC :fish:
Functional hearing loss
:birthday:
Criteria
No organic causes
of deafness
Normal peripheral hearing mechanism
If got slight damage (little trauma) to peripheral end-organ ➯ observed HL is
disproportionate
to organic lesion
Characteristic features
Varies hearing acuity (depends on pt emotional state)
Inconsistency in results of two or more tests
:silhouette:
Type of Pt
Malinger
Abandon his symptoms when คิดว่าไม่มีใครมองเห็น
สนใจสวล. ไม่สนใจตัวเอง
Neurotic pt
Pt กลุ่มใจ hearing status ของตัวเอง
Interfere with his pleasure