Understanding Neurology

Disorders of cognition 9587 Diagram to illustrate theanatomy of articulation.CerebellumRB4A3L211 Speech initiated87234Descending cortico-bulbar pathway from lefthemisphere to nuclei X and XIIConnection through corpus callosum to motorcortex of right hemisphereDescending cortico-bulbar pathway from righthemisphere to nuclei X and XIIA - Cortico-bulbar pathwayB - CerebellumC - Extrapyramidal systemD - Nuclei of lower neurons of X, XII cranial nervesCAHypoglossal nucleus andnerve (XII) to tongueDNucleus ambiguus ofvagus nerve (X)supplying soft palate,pharynx and larynxThe extrapyramidal andcerebellar systems modulatearticulatory muscle actiondeep systems, but the deep system overrules, and theword is pronounced correctly (88). Should readingaloud be required, Broca’s area is activated, and theabove cascade occurs. Writing requires motor areascontrolling hand movements to be involved in theproduction of written symbols.Written wordVisual analysis88Pathology of language and speechIn caring for a patient with an apparent disorder ofspeech or language, the clinician must first establishwhether there is a true language impairment (i.e. adysphasia), or whether the deficit is due to moreperipheral damage. If there is an apparent deficit incomprehension of language, it is important toestablish whether basic hearing and vision aresufficient to allow the heard or seen word to bepassed upstream to become accessible to language, orwhether it is a true language deficit. Similarly, interms of speech output, it is again important toestablish whether there is a true language outputdisorder (i.e. expressive dysphasia), or whether theproblem is more peripheral (i.e. impaired motorcontrol of facial and vocal musculature to allowspeech expression). Dysphasia refers to a loss ofcomprehension, production, or both of spoken(and/or written) language. Dysarthria refers to poorarticulation of speech yet with language intact.Analysis bymeaningSpeech outputSpoken wordAnalysis bysound88 Diagram to illustrate the dual route hypothesis of reading.