Schwerhörigkeit aufgrund der Otitis externa als Folge eines Kopftraumas und Verhaltensstörung aufgrund einer Taubheit beim Pferd.

A horse with head trauma induced by falling can have a traumatic brain injury or a fracture of the ossea part of the external ear canal. The aim of this study is to find the complications of a head trauma. The aim of the second study is to verify the deafness as a cause of behavioral disorder in horses. A three-year-old Hannoverian gelding fell down and injured the left lateral region of his head. After getting up the gelding had a bloody discharge out of the left ear. The neurological exam had shown slowly ear movements, painful left ear basis and left head tilt. The endoscopy of the guttural pouches was normal. The CT image detected a transversal fractur of the left osseus part of the external ear canal. Thirteen weeks after falling down the otoscopy of the cartilaginous and osseus part including the tympanic membrane of the right ear were normal (grading I/III). The protrusion caused by the fracture in the osseus part of the left ear prevented the view to the tympanic membrane. The epithelium of the osseus part was severe reddened and swollen which are signs of an acute external otitis. The threshold of normal hearing level of the right ear was 30 dB. The brainstem auditory evoked response (BAER) of the right ear showed prolonged latencies of wave III (2.95 ms, normal 2.86) and V (5.80 ms, normal 4.62) and interpeak latencies I-III (1.65 ms, normal 1.33) and I-V (4.50 ms, normal 1.76) which were showing a mild sensorineurale hearing deficit based on traumatic brain injury. This traumatic brain injury could induce an axonal damage of the brainstem auditory pathway. The threshold of normal hearing level of the left ear was 80 dB. BAER of left ear had no identifiable peaks and therefore no measurable latencies and interpeak latencies. These findings concluded to the diagnosis of sever conductive hearing deficit based on the protrusion in the left osseus part in this gelding with head trauma. The behavioral disorders of American Paint Horses were observed by the owners and these horses were refered to the equine medical clinic. The otoscopical findings of all horses were normal in the cartilaginous and osseus part (grading I/III). Achromodermia was found in all cartilaginous parts of the external ear canals. Only one horse had keratin scales around the entrance of the osseus part in both ears. All tympanic membranes were intact and transparent. The thresholds of normal hearing level on both ears of all horses were 100 dB. Absent peaks of the BAER and isoelectric lines were seen which characterize the sensorineurale deafness in all American Paint Horses. The sensorineural deafness was the reason of the behavioral disorder described by the owners. Horses with head trauma suffer from a traumatic brain injury. These horses could have a hearing deficit based on either due to a fracture of the osseus part of the external ear canal or an acute external otitis or both. Endoscopy of the guttural pouches, external ear canals and BAER should be done. Hearing deficit or deafness induce behavioral disorders which should know the owner. Horses with white head and blue eyes could have the genetical deafness. Deafness will be diagnosed with BAER. [ABSTRACT FROM AUTHOR]