Stuttering Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! ===History of causes=== Auditory processing deficits have also been proposed as a cause of stuttering. Stuttering is possibly less prevalent in deaf and hard-of-hearing individuals,<ref>{{harvnb|Ward|2006|pp= 46β7}}</ref> and stuttering is occasionally reduced when auditory feedback is altered, such as by [[Auditory masking|masking]], [[delayed auditory feedback]] (DAF), or frequency altered feedback.<ref>{{harvnb|Ward|2006|p= 58}}</ref> There is evidence of differences in linguistic processing between people who stutter and people who do not.<ref>{{harvnb|Ward|2006|p= 43}}</ref> Brain scans of adult stutterers have found greater activation of the right hemisphere, which is associated with emotions, than of the left hemisphere, which is associated with speech. In addition, reduced activation in the left auditory cortex has been observed.<ref name="gordon"/> The ''capacities and demands'' model has been proposed to account for the heterogeneity of the disorder. In this approach, speech performance varies depending on the ''capacity'' that the individual has for producing fluent speech, and the ''demands'' placed upon the person by the speaking situation. Demands may be increased by internal factors or inadequate language skills or external factors. In stuttering, the severity of the disorder is seen as likely to increase when demands placed on the person's speech and language system exceed their capacity to deal with these pressures.<ref>{{harvnb|Ward|2006|pp= 16β21}}</ref> However, the precise nature of the capacity or incapacity has not been delineated. Another theory is that adults who stutter have elevated levels of the neurotransmitter [[dopamine]], and have thus found [[dopamine antagonist]]s that reduce stuttering.<ref name=":4">{{Cite book|title=A handbook on stuttering|last1=Bloodstein|first1=Oliver|last2=Ratner|first2=Nan Bernstein|publisher=Cengage Learning|year=2007|isbn=978-1-4180-4203-5|pages=142}}</ref> Overactivity of the midbrain has been found at the level of the substantia nigra extended to the red nucleus and subthalamic nucleus, which all contribute to the production of dopamine.<ref name=watkins /> However, increased dopamine does not imply increased excitatory function since dopamine's effect can be both excitatory or inhibitory depending upon which dopamine receptors have been stimulated. {{main|Dopamine hypothesis of stuttering }} It was once thought that forcing a left-handed student to write with their right-hand caused stuttering due to [[bias against left-handed people]], but this myth died out.<ref>{{cite journal|pmc=1591462|first=Ruth|last=Lewis|date=May 1949|pmid=18125462|volume=60|issue=5|journal=Can Med Assoc J|pages=497β500|title=The psychological approach to the preschool stutterer}}</ref><ref>{{cite journal|url=http://jhered.oxfordjournals.org/content/24/10/387.full.pdf|title=LEFT-HANDEDNESS AND STUTTERING|first1=Bryng|last1=Bryngelson|first2=Thomas B.|last2=Clark|journal=The Journal of Heredity|year=1933|volume=24|issue=10|pages=387β390|access-date=January 3, 2011}}{{dead link|date=May 2021|bot=medic}}{{cbignore|bot=medic}}</ref><ref>{{cite journal|author1=Johnson, W. |author2=L. Duke |year=1935|title=Changes in handedness associated with onset or disappearance of stuttering; sixteen cases|journal=Journal of Experimental Education|volume=4|pages=112β132|doi=10.1080/00220973.1935.11010003 }}</ref> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page