ABSTRACT | PDF

SEMINAR

Speech

Susmita Hazarika 
Postgraduate Trainee of Psychiatry 
Silchar Medical College and Hospital
  

Introduction Speech can be described as the mechanical portion of an individual’s ability to communicate with oral language, demanding combination of the appropiate neuromuscular actions necessary for phonation and articulation.

Anatomy of language area Four main language areas are situated in most persons in left cerebral hemisphere. Two language areas are receptive and two language areas are executive. Receptive areas are closely related and are referred to as central language zone. One subserves the perception of spoken language, occupies posterior posterosuperior temporal area (posterior portion of Broadmann area 22) and Heschl’s gyri (areas 41 and 42). Posterior portion of area 22 in planum temorale is referred to as Wernicke’s area. Another one subserves the perception of written language, occupies the angular gyrus (area 39) in inferior parietal lobule, anterior to visual receptive area.

Broca’s area is main executive area, situated at the posterior end of inferior frontal convolution (areas 44 and 45). It is concerned with the motor aspect of speech. It controls the output of spoken language by innervating the adjacent motor neurons subserving the mouth and larynx. Visually percieved words are given expression in writing through a fourth language area, the so-called Exner writing area in posterior portion of the second frontal convolution.

Arcuate fasciculus is a rich network of nerves connecting sensory and motor areas of speech with one another which passes through the isthmus of temporal lobe and around the posterior end of sylvian fissure. Subcortical white matter of the insula is another network of nerves which traverses the internal capsule of the lenticular nucleus. Short association fibres join the Broca’s area with the lower rolandic cortex which in turn innervates the speech apparatus i.e., muscles of lips, tongue, pharynx and larynx. Other regions of the cerebrum contribute importantly to normal language. These include several frontal and temporal lobe regions that support sentence-level processing, and vast regions of temporal, occipital, and parietal cortex that support knowledge of words and their meanings.

Mechanism of speech Spontaneous speech is organized in Wernicke’s area. Here the person finds words to express himself and link them into meaningful sentence. The Wernicke’s area patterns of activity representing what is to be said and then sent through the arcuate fasciculus to Broca’s area, which contains the programs for complex patterns of muscle movement needed in speech. The vocal area programs are then relayed to the motor cortex controlling the lips, tongue and vocal cord which actually produce the speech sound.

To speak a word that is read, information must first get to the primary visual cortex. From the primary visual cortex, information is transmitted to the posterior speech area, including Wernicke's area. From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex, so that actual muscles contract and the person utters the word. To speak a word that is heard, information must first get to the primary auditory cortex. From the primary auditory cortex, information is transmitted to the posterior speech area, including Wernicke's area. From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex, so that actual muscles contract and the person utters the word.

Cerebral dominance Most individuals are left hemisphere dominant for language function. Cerebral dominance is influenced by handedness; of the 90 to 95 percent of people who are right handed, more than 95 percent have left-sided language dominance. A smaller proportion of left-handed individuals, variably estimated between 31 to 70 percent, have left-sided language dominance.

Language communication Starting with the basic sounds of speech, spoken language can be broken down into following elements - phonems, syllables, morphemes, words, clauses, sentences. Speech sounds or phones are made by adjusting the vocal cords and moving the tongue, lips and mouth in wonderfully precise ways to produce vibrations in the airflow from the lungs. Although there are hundreds of speech sounds, only a limited number (45 in English) of phones are important in understanding of speech. They are known as phonemes. Two or three  phonems are combined into a syllable. It is the smallest unit of speech perception. Morphemes are the smallest unit carrying the meaning in speech perception. Morphemes can be prefixes, words or suffixes e.g., distasteful - composed of three morphemes dis,taste,ful. Words are combined by rules of grammar into clauses. A clause consist of a verb and associated nouns, adjectives and so on.

Development of language Babbling, cooing and lalling stages in first few weeks. At about six months, babbling sounds in the form of vowel-consonant combination. Gradually babbling merges with echo speech in which short sounds are repeated parrot-like. At 12 months, speaks one or two words. In second year of life, child begins to use word combination. At 18 months, can combine an average of one and half words. At two years, can combine two words. At two and half years, can combine three words. At three years, can combine four words. Ninety per cent of children can articulate all vowel sounds by the age of three years, consonants at a little later age. Girls tend to accquire articulatory facility somewhat earlier than boys. Vocabulary increases so that by 18 months child knows six to 20 words, by 24 months 200 to 300 words, by three years 900 to 1000 words. Able to tell stories by four years. By five years has an average of over 2300 words. By six years defines words by function and attributes.

Next stage of language development is reading. There must be an association of graphic symbols with the auditory, visual and kinesthetic images of the words already accquired. The integrity of Wernicke’s area and contagious parieto-occipital area of the dominant hemisphere are essential to the establishment of these cross-modal associations.

Physical characteristics of speech In terms of type, talkative, garrulous, voluble, taciturn or normally responsive. In terms of rate of production, rapid or slow. In terms of quality, monotonous, loud, whispered, pressured or hesitant. Poverty of speech is restriction in the amount of speech. Replies may be monosyllabic. Found in major depression. Laconic speech is decrease in the quantity of spontaneous speech. Found in major depression, schizophrenia, organic mental disorders. Pressured speech is increase in the amount of spontaneous speech; rapid, loud, accelerated speech. Logorrhea is copious, pressured, coherant speech with uncontrollable excessive talking. Found in manic episode of bipolar disorder. Loosening of association is charecteristic schizophrenic thinking or speech disturbance involving a disorder in the logical progression of thoughts manifested as a failure to communicate verbally adequately; unrelated and unconnected ideas shift from one object to another.

Developmental disorders of speech and language 1. Developmental speech delay: Most children say their first word between nine to 12 months and first word combination before second birthday. Children who fail to reach these milestones fall into two categories. Otherwise normal children who talk late. More common in boys. Family history of delayed speech often present. Eventually when the child talks, he may skip the initial stages of spoken language and develop fluent speech and language. Pathological basis is common. Common in cerebral palsy, mental retardation.

2. Congenital deafness: Found in congenital rubella, erythroblastosis fetalis, bilateral ear infection, meningitis, administration of ototoxic drugs to pregnant mothers or new born infant. Deaf child makes transition from crying to cooing and babbling at the usual age of three to five months. After six months child becomes quieter and repertoire of  babbling sounds become stereotyped and unchanging. Babbling fails to give way to words.

3. Congenital word deafness: Also called developmental receptive dysphasia, verbal auditory agnosia or central deafness. A word deaf child responds to loud noises and music but dos not understand spoken words. The receptive auditory elements of dominant temporal cortex fail to discriminate the complex acoustic pattern of words and to associate them with visual images of people and images.

4. Congenital inarticulation: The child seems unable to coordinate the vocal, articulatory and respiratory musculature for the purpose of speaking. Boys more affected than girls. Often family history is seen.

5. Stuttering and stammering: It represents a disorder of rhythm - an involuntary, repetitive prolongation of speech due to an insuppressible spasm of aticulatory muscles.

6. Cluttering or cluttered speech: It is characterised by uncontrollable speed of speech, which results in truncated, dysrhythmic and often incoherent utterances. Omission of consonants, improper phrasing and inadequate intonation occurs.

7. Other  defects: Lipsing – s sound is replaced by th. Lallation or dyslalia – multiple substitution or omissions of consonants.

Disorders of speech and language 1. Stammering and stuttering: Normal flow of speech is interrupted by pauses or by repetition of fragments of the word. Grimacing and tic-like movements of the body are often associated with the stammer. Found in onset of acute schizophrenia, severe adolescent crisis. Stuttering - Condition in which the flow of speech or fluency is disrupted by involuntary speech motor events. More common in boys. It improves with time. Noticed commonly in anxiety states.

2. Mutism: Complete loss of speech. May occur in children with a range of psychiatric disorders. In adults, seen in hysteria, depression, schizophrenia, organic brain syndrome, catatonic stupor. Most common hysterical disorder of speech is aphonia. Severe depression with psychomotor retardation may be present in mutism. Elective mutism may occur in children who refuse to speak to certain people e.g., at school.

3. Talking past the point (Vorbeireden): In this disorder the content of the patient’s replies show that they understand what has been asked but have responded by talking about an associated topic. Found in hysterical pseudodementia, acute schizophrenia among adults, catatonic states. Approximate answers may be a feature of Ganser’s syndrome.

4. Neologims: Neologisms may be new words that are constructed by the patient or ordinary words that are used in a new way. It is usually applied to new word formation produced by individuals with schizophrenia. Technical neologism: Sometimes neologisms seem to an attempt to find a word for an experience that is completely outside the realms of normal. Patient makes up a technical term for a private experience that cannot be expressed in ordinary words. Hallucinatory voices also lead to neologism. Voices use neologism and this may lead the patient to use them as well. Paraphasia: Some patients with aphasia use wrong words, invent new words or distort the phonetic structure of words.

5. Speech confusion and schizophasia: Individuals with schizophrenia produce speech that is profoundly confused, but are able to carry out responsible work that does not involve the use of words.

6. Logoclonia: The spastic repetition of words that occur in parkinsonism. The patient may get stuck using a particular word.

7. Pseudologia fantastica: A condition of fluent plausible lying, often associated with histrionic or asocial personality disorders.

8. Echolalia: The patient repeats words or parts of sentences that are spoken to him or in his presence. There is usually no understanding of the meaning of words. Found in excited schizophrenic states, mental retardation, dementia.

9. Changes in volume and intonation of speech: Depressed person speaks in monotonous voice. Manic patient often speak loudly and excitably with variation in pitch. Schizophrenics may also speak loudly - intonation and stresses on words may be idiosyncratic and inappropriate.

10. Unintelligible speech: Dysphasia may lead to unintelligible speech. Paragrammatism (disorder of grammatical construction) and incoherence of syntax may occur in several disorders. Recognizable words may be so deranged in a sentence as to be meaningless - word salad which occurs in schizophrenia. Private symbolism may occur in schizophrenia e.g., neologism, stock words and phrases - existing words are used with special individual symbolic meaning, cryptolalia - a private language may be spoken, cryptographia - a private language may be written.

11. Aphasia: Aphasia or dysphasia is a loss or impairment of production and/or comprehension of the spoken or written language due to lesion of some areas of the brain.

Clinical varieties of aphasia

A. Wernicke’s aphasia: Due to involvement of posterior part of superior temporal gyrus, an area generally considered to be the auditory association cortex and called Wernicke’s area. It is adjacent to primary auditory cortex (Heschl’s gyrus) which may or may not be involved in Wernicke’s aphasia.

Verbal output is characterised by features of fluency with normal or excessive number of words produced per minute. Output can be so excessive that patient may speak continuously unless forcefully stopped by the examiner - pressure of speech or logorrhea. The content of Wernicke’s aphasia shows deficiency of meaningful, substantive words, ideas of individuals are not effectively conveyed - empty speech.

Paraphasia - most  characteristic type of substitution is verbal. If patient produces an excessive number of words with multiple paraphasic substitution, the output becomes completely incomprehensible - jargon aphasia. There is associated problem in comprehension of spoken language. Repetation of spoken language is invariably disturbed. Reading is always disturbed. Writing is also abnormal. Patient can use his dominant hand for writing and the output consists of well formed, legible letters combined in a meaningless manner. On neurological examination, little or no paresis, some cortical sensory disturbance, superior quadrantanopsia. Causes include cerebrovascular accident, tumour or abscess in temporal lobe.

B. Broca’s aphasia: The verbal output in Broca’s aphasia can be described as nonfluent. Speech is sparse, poorly articulated, consists of very short phrases, is produced with considerable effort, particularly on initiation of speech and is dysprosodic. The comparatively rich substantial quality of output enables the patient to communicate some ideas despite deficiency in verbal output. Comprehension of spoken language is always better than verbal output. Repetition of spoken language is always abnormal. Patients with Broca’s aphasia find it difficult to read out loud. Writing is always abnormal. Handwriting consists of oversized, poorly formed letters, multiple misspellings, omission of letters. On neurological examination, some degree of right sided motor weakness, hyperactive reflexes on affected side, sensory abnormalities in the form of loss of pain and cortical sensory function, visual field defects. Causes include occlusion of middle cerebral artery feeding inferior frontal region, tumuor, abscess, infection, vascular lesion in the frontal region.

C. Conduction aphasia: The damage to the anatomical connection between the temporal lobe and posteroinferior frontal lobe produces conduction aphasia. Comprehension of spoken language is good in conduction aphasia. Problem remains in repeating spoken language. There is problem in reading out loud with rapid breakdown into severely paraphasic output. But can read silently with ease. Writing is disturbed. Patient can write some words and produce well formed letters but spelling is poor with lot of omission and substitution of letters. On neurological examination, often no neurological deficit, unilateral paresis, limited sensory loss, hemianopia, upper or lower quadrantanopsia. Causes include cerebrovascular accident, occlusion of a portion of of middle cerebral artery (MCA), tumour, trauma.

D. Total or global aphasia: This syndrome is due to destruction of a large part of the language zone, embracing both Broca’s and Wernicke’s areas and much of the territory between them. Patient can speak only a few words. May understand a few words and phrases but fail to carry out commands or to name objects because of rapid fatique and verbal and motor perseveration. On neurological examination, varying degree of right hemiplegia, hemianaesthesia and homonymous hemianopia found in global aphasia of vascular origin.

E. Pure word deafness: Characterised by impairment of auditory comprehension and repetition, inability to write to dictation. Self initiated utterances are sometimes correctly phrased but are sometimes paraphasic. Spontaneous writing and ability to comprehend written language is preserved. Lesion is in middle third of superior temporal gyrus.

F. Pure word blindness: Person loses the ability to read aloud. Patient loses the ability to understand written script and often to name colours, to match a colour to its name - visual verbal colour anomia. Understanding spoken words, repetition, writing to dictation, conversation are all intact. Alexia without agraphia - patient is able to write fluently, after which he cannot read what is written. Lesion that destroy left visual cortex and underlying white matter.

G. Pure word mutism: Patient loses all ability to speak, while retaining perfectly the ability to write, to understand spoken language, to read silently with comprehension and to repeat spoken words. Due to vascular lesion or localized injury of the dominant frontal lobe.

H. Anomic aphasia: Patient loses ability to name people and objects. He may tell the use of objects instead of naming them. Lesion in deep basal portion of posterior temporal lobe or in the middle temporal convolution, in a position to interrupt connection between hippocampal region concerned with learning and memory. Causes may be tumour, herpes encephalitis, abscess.

I. Transcortical aphasia: In transcortical sensory aphasia, patient suffers a deficit of auditory and visual word comprehension, writing and reading impossible but repetition remarkably preserved. Speech is fluent with paraphasia and empty circumloculation. In transcortical motor aphasia, patient is unable to initiate conversational speech, producing only few grunts or syllables. Comprehension is preserved but repetition is strikingly intact. Due to destruction of border zone of anterior, middle and posterior cerebral arteries, which isolates motor and sensory areas from rest of the cortex.

J. Subcortical aphasia: A lesion of the dominant thalamus, usually vascular may cause an aphasia, the clinical features of which are not clear. Usually there is mutism and comprehension is impaired. Reading and writing may or may not be affected.

12. Dysarthria: There is difficulty in articulation of speech. It is mainly due to muscular/neuromuscular disorder. There is no abnormality in cortical language mechanism.

a. Cerebellar dysarthria: There is involvement of cerebellum and brain stem. Patient speaks deliberately slowly and in a scanning manner.

b. Pseudobulbar dysarthria: Here the lesion is in corticospinal tract above the level of brain stem nuclei. Patient has slurring of speech.

c. Bulbar dysarthria: This is due to weakness or paralysis of articulatory muscles, the result of disease of motor nuclei of medulla and lower pons or their intermedullary or peripheral extensions. Patient has nonspecific slurring of speech.

d. Rigid (extrapyramidal) dysarthria: Characterised by rapid utterance and slurring of words and syllables and trailing off in volume at the end of sentences. The voice is low pitched and monotonous. Found in parkinsonism.

13. Dysphonia: Speech disorder due to disturbances of phonation. Here there is production of abnormal sounds due to defect within larynx or recurrent laryngeal nerve.

Speech therapy 1. Phonological approach: Exercises in this approach to treatment focus on guided practice of specific sounds such as final consonants. And when that skill is mastered practice is extended to use in meaningful words and sentences. Used for children with multiple patterns of speech sound errors like consonant deletion or consonant cluster reduction.

2. Traditional approach: Used for children who produce substitution or distortion errors in just few words. In this the child practices the production of the problem sound while the clinician provides immediate feedback and cues concerning the correct placement of the tongue and mouth for improved articulation.

Recent advances Specific interventions — Management of speech and language impairment may include one or more of the following: Enrollment in individual or group speech and language therapy. Therapy through a private facility or the public school system. Attendance at a specialised school for children with speech, language, and learning differences. Further assessment in specific areas (e.g., oral, motor, psychological). Application of assistive technology. Periodic monitoring without direct therapy.

Investigational therapies — Facilitated communication (FC), auditory integration training (AIT), sensory integration (SI) therapy, and Fast ForWord are examples of controversial practices that have not yet been validated in large, controlled trials.

References

1. Kaplan & Sadock’s  Comprehensive textbook of psychiatry, 9th edition - Benjamin J Sadock  and  Virginia  A Sadock

2. Synopsis of psychiatry, 10th edition - Benjamin J  Sadock and Virginia A Sadock

3. Introduction to psychology, 7th edition - Morgan and  King

4. Adam’s and Victor’s Principles of neurology, 7th edition - Maurice Victor,  Allan H. Ropper

5. Symptoms in the mind, 3rd edition - Andrew  Sims

6.Fish’s clinical psychopathology - Casey and Kelly

7.Aphasia, alexia, agraphia - D Frank Benson

8. Internet

 

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