Dr. Mohommed Moizuddin Khan Dr Beenish Mukhtar

At the end of this lecture the students should: Describe brain speech areas as Brocas, Wernickes and insula Explain sequence of events in speech production Explain speech disorders as aphasia with its types, dysarthria, and acalculia Explain difference between aphasia and dysarthria.

Speech is complex form of communication in which spoken words convey ideas. Verbal behaviors constitute one of the most important classes of human social behavior. Language is one of the fundamental bases of human intelligence and a key part of human culture.

Speech Centers: Broca’s area Wernicke’s area motor speech area Wernicke’s area sensory speech area Both connected by Arcuate Fasciculus. Both areas also interact with association areas.

Broca’s area It is located in left frontal lobe just in front of the base of Primary motor cortex. Function: It is for Articulation – Word formation Broca’s area contains motor memories — in particular, memories of the sequences of muscular movements that are needed to articulate words. Broca's area excites Motor area which controls the muscles necessary for articulation.

Function: It is concerned with language comprehension (understanding). Wernicke’s area It is located in the left cortex at Superior gyrus of Temporal lobe at the juncture of parietal, temporal and occipital lobes. Function: It is concerned with language comprehension (understanding). It plays important role in understanding of both spoken and written messages. Wernicke’s area receives input from visual cortex and also auditory cortex.

Is a axon pathway between Wernicke’s area and Broca’s area Arcuate Fasciculus Is a axon pathway between Wernicke’s area and Broca’s area Higher-Order Association Cortex Wernicke’s area has connections with various association areas in … Left Frontal Left Temporal Left Parietal Are involved with mediating between concepts and language

SPEECH

SPEECH

Steps are: Reception in the primary auditory cortex area of sound signals. Interpretation of words in Wernicke's area. Determination of thoughts in words to be spoken in Wernicke’s area. Transmission of signals from Wernicke’s area to Broca’s area by Arcuate fasciculus. Word formation in Broca’s area. Transmission of signals to motor cortex to control the speech muscles.

Steps are: Reading the words – reception in primary visual area. Information passes through angular gyrus region and reaches Wernicke's area. Interpretation of words in Wernicke's area. Determination of thoughts in words to be spoken in Wernicke’s area. Transmission of signals from Wernicke’s area to Broca’s area by Arcuate fasciculus. Word formation in Broca’s area. Transmission of signals to motor cortex to control the speech muscles.

Lateralization: Speech area are located in one sphere (on one side), usually the dominant hemisphere. Left hemisphere is dominant for fine movements in most Right handed people. Also in many Left handed people. Left hemisphere is therefore called DOMINANT SPHERE.

Although the circuits that are primarily involved in speech comprehension and production are located in one hemisphere (almost always, the left hemisphere), the Right hemisphere does have its role in speech. Damage to the right hemisphere makes it difficult for a person to read maps, perceive spatial relations, and recognize complex geometrical forms. The right hemisphere also appears to be involved in organizing a narrative—selecting and assembling the elements of what we want to say. The right hemisphere is involved in the expression and recognition of emotion in the tone of voice.

Damage to Brocas’s area: (Motor Aphasia) It results in failure of word formation. Patient can understand the spoken and written words. These people know what they want to say, but can not express themselves. This disorder is characterized by slow, laborious, and non-fluent speech. Although they often mispronounce words, the ones the patients manage to come out with are usually meaningful. In general, three major speech deficits are produced by lesions in and around Broca’s area: agrammatism, anomia, and articulation difficulties.

SPEECH DISORDERS Damage to Wernicke’s area: (sensory aphasia) These patients can not understand the words they hear or see. What they say is full of jargon and neologisms that make little sense. They can speak fluently, their articulation is perfect, but their speaking makes no sense because they can not attach meaning to words to convey their thoughts.

SPEECH DISORDERS Conduction Aphasia: Patients may be able to understand speech as well as produce meaningful speech, but have difficulty repeating a spoken sentence. Associated with damage to the Arcuate Fasciculus, which connects Wernicke’s area with Brocas area & frontal pre-motor structures.

Acalculia is an acquired impairment in which patients have difficulty performing simple mathematical tasks, such as adding, subtracting, multiplying and even simply stating which of two numbers is larger.

SPEECH DISORDERS Anomic aphasia (anomia): Due to damage to angular gyrus Is a type of aphasia characterized by problem recalling words, names, and numbers. Subjects often use circumlocutions (speaking in a roundabout way) in order to avoid a name they cannot recall or to express a certain word they cannot remember.

SPEECH DISORDERS Global Aphasia: - Damage occurs to both Broca’s area and Wernicke's area. Patient can not understand or speak.

SPEECH DISORDERS

SPEECH DISORDERS Speech Disorders of Articulation (Dysarthria) Occurs due to weakness of articulating muscles in-coordination of articulating muscles Mechanical factors Ill fitting dentures Weakness of oro-lingual muscles concerned with speech Problem may be in muscle, nerve supply or cerebellum Cerebellar lesions causes dysarthria, speech is with increased word length. it is called scanning speech. Dysarthria in Parkinsonism Speech is monotonous, slurring dysarthria

SPEECH DISORDERS STAMMERING SPEECH: It is a speech disorder, where person prolongs the word usually at vowels (a,e,i,o,u). e.g. To-to-to-to-morrow Mmmmmmm ilk Commonly occurs by age of 2½ to 3 ½ years. Factors which precipitate – stress. Majority of children grow out of it but in some it remains and requires speech therapy. Dysphonia: In Dysphonia, sound is not pronounced properly. Dysphonia is usually due to laryngeal problem.

SPEECH DISORDERS Speech center are found in one hemisphere i.e. left side. But if a child below 2 years has damage to left cerebral hemisphere then language function are transferred to right hemisphere with no delay in language development. This is due to plasticity or remodeling of brain in response to varying demands.

SPEECH DISORDERS Up to the age of 10 years, if damage occurs to left hemisphere, language activity can be re-established in the right hemisphere after a temporary period of loss. After 10 years, there may be permanent loss of speech as regions of brain involved in spoken and understanding speech are permanently assigned before 13 to 15 years.

Human physiology by Lauralee Sherwood, 9th edition Text Book Of Physiology by Guyton & Hall, 11th edition Review of Medical Physiology by Ganong, 24th edition

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