4.1.13 What later discoveries have added to this knowledge?

Some later discoveries that have added knowledge are the neurophysiological model of tinnitus and the science of brain plasticity.

The science of brain plasticity over the last twenty years has proven that new brain pathways are created as a result of stimulation.

Therefore, we now know that listening to Sound Therapy physically builds and enhances our neural network.

Sound impacts not just our hearing but our entire nervous system, via the cranial nerves. (Weeks, 1989) In fact ten out of our twelve cranial nerves are linked in some way to the ear.

The auditory (8th cranial nerve) controls balance and hearing. A branch of this nerve arborises around (surrounds) the 3rd or oculomotor nerve. This means that the four cranial nerves concerned with vision are to some extent controlled by the auditory nerve.

The trigeminal (5th cranial nerve) is the major nerve of the head, face and jaw. This nerve controls the tension on the ear drum via the tensor tympani muscle. It therefore plays a significant role in the voluntary act of listening.

The facial (7th cranial nerve) controls facial expression and also the door to the inner ear chamber via the stapedius muscle. Thus it influences balance as well as the inner receptivity to sound.

The glossopharyngeal (9th cranial nerve) links hearing and speech. It contacts several parts of the ear concerned with pressure and links them to the tongue and throat.

The vagus (10th cranial nerve) accounts for the powerful relationship between hearing and emotion. After sending a twig across the ear drum the vagus wanders through the larynx, chest, heart, stomach and intestine, enabling our hearing to have an effect on all these organs.

The spinal accessory (11th cranial nerve), affecting posture in the neck and shoulders is also linked to the ear via its connection with the vagus.

Thus we see that the ear is not just a minor part of the nervous system, but is intricately and centrally linked with nearly all of our sensory processing mechanisms, placing it in a primary position as coordinator of our interface with the world.

The Twelve Cranial Nerves — Table

No. Name Contact with ear Primary function/

organs of contact

1 Olfactory Olfactory bulb – smell
2 Optic Interacts with 8th Eyeball – sight 3rd
3 Occulomotor Under control of 8th Link between hearing and sight

Movement of the eye

4 Trochlear Under control of 8th Turns eye up and down 3rd – lateral sinus upper jaw
5 Trigeminal Ear Drum

Outer ear canal

Tensor tympani

Link between face, jaw and middle ear

The great sensory nerve of the head and face

Motor nerve muscles of mastication

Upper eyelid, facial nerve, forehead, nose, iris, cornea, teeth, lower eyelid, upper lip and lower lip, mucous membrane of mouth, palate, gums, uvula, tonsils, Eustachian tube, muscles of mastication, tempero-mandibular joint, tongue
6 Abducent Under control of 8th Eye movement Optic, oculomotor
7 Facial Stapedius


Chorda tympani



Link between face and inner ear

Facial expression

Taste – back of tongue

Upper part of neck muscles behind ear on back of pinna

3rd, 10th, 9th, 5th

Shares filaments with auditory nerve in meatus

8 Auditory Inner ear Hearing and balance Oculomotor

Vestibular – arborises around the nuclei of the oculomotor nerve


Cochlear-facial nerve in meatus

9 Glossopharyngeal Oval window

Round window


Eustachian tube

Link between hearing and speech



Tongue – taste

Spinal accessory

10 Vagus/ Pneumogastric Tympanum

Posterior auricular nerve

Meatus, pinna

Link between hearing and emotion

Neck thorax/chest, abdomen

Motor sensory – voice, respiration

Motor – heart, stomach glossopharyngeal, facial, spinal accessory

11 Spinal Accessory Interacts with vagus Link between hearing and posture

Spinal, neck and trapezius

Vagus – pharynx, larynx

2nd, 3rd, 4th cervical nerve

12 Hypoglossal Motor nerve of tongue


1st and 2nd cervical nerves, lingual