Sunday, 2 November 2008

Sound is recieved in two ways, via bone conduction (when sound waves hit the body and are transmitted to the vestible) and air conduction (when sound waves pass through the ear canal and are analysed by the cochlea). The vestible can also be stimulated in two ways, either through motor movement or sound. Now I'm borrowing from a web-page on Attention Deficit/ Hyperactivity Disorder which can be found here....

I'll quote from it:"Because some children with AD/HD have weak auditory systems and cannot process sound effectively, they might compensate for the vestible's lack of sound stimulation by increased motor activity. Hyperactivity may be a symptom of an under-stimulated vestible."

"There are no tests that can conclusively determine whether a child has AD/HD, but an EEG (Electroencephalogram) can reveal abnormal brainwave patterns. While EEGs can be employed as a diagnostic tool, this technology is not generally used in a diagnosis of AD/HD as there are other guidelines that are simpler and more appropriate [3]. However it can be used in a form of treatment known as EEG Biofeedback/Neurofeedback. EEG Biofeedback is complemented by the Tomatis Method of sound stimulation which retrains the ear to become less dependent on motor activity for vestibular stimulation. It also strengthens the auditory system and enables selective listening so that the child is no longer overwhelmed by auditory information [7]. Other sound stimulation techniques may also be used, such as The Listening Program®, and Neuro Developmental Therapy may also be recommended. "

Then I found an article about lizards which speed up visual displays in noisy motion habitats...

The article is referring to the visual display of the anole lizard which communicate using vertical movements of the head, known as head-bobs, and an expandable throat fan or dewlap. These displays are critical for males in the maintenance of territories that overlap those of sexual females. (Stamps 1983) In summary of this article then, they found high levels of background noise (windblown vegetation) produced high speed displays, while males experiencing calmer conditions produced more relaxed displays of lower speed.

Now I realise I am making an awkward shift from auditory systems and kids with AD/HD, to visual systems and anole lizards, but I am struck by an intriguing similarity: both parties increase motor activity to over-compensate background interference. Are the lizards also stimulating the vestible for whatever reason? Where am I going with this? Lord knows.

No comments: