APHASIAAPHASIA

Speech and LanguageSpeech and Language

• Not synonymousNot synonymous• Derangement of languageDerangement of language functionfunction is is

always a reflection of an always a reflection of an abnormality of abnormality of the brainthe brain – of the – of the dominant hemispheredominant hemisphere

• Disorder of speechDisorder of speech – may be a result of – may be a result of abnormalities in different parts of the abnormalities in different parts of the brain/ or to extracerebral mechanismbrain/ or to extracerebral mechanism

- refers to the - refers to the articulatory and phonetic aspects of verbal articulatory and phonetic aspects of verbal expressionexpression

• AphasiaAphasia= loss or impairment of the = loss or impairment of the production or comprehension of production or comprehension of spokenspoken or or writtenwritten language language

• Dysarthria and anarthriaDysarthria and anarthria= defect in = defect in articulation with intact mental articulation with intact mental functions and comprehensionfunctions and comprehension

• Dysphonia or aphoniaDysphonia or aphonia= alteration or = alteration or loss of voice because of a disorder of loss of voice because of a disorder of the larynx or its innervationthe larynx or its innervation

• The dominance of one hemisphere – The dominance of one hemisphere – usually the left -emerges in brain usually the left -emerges in brain development together with speech development together with speech and the preference of the right hand, and the preference of the right hand, especially its use for writing.especially its use for writing.

• Language functionLanguage function lateralizes to the lateralizes to the left left

hemisphere in 96-99% of right-handed hemisphere in 96-99% of right-handed peoplepeople and 60% of left-handed people. Of and 60% of left-handed people. Of the remaining left-handed people, about the remaining left-handed people, about one half have mixed hemisphere one half have mixed hemisphere language dominance, and about one half language dominance, and about one half have right hemisphere dominance. Left-have right hemisphere dominance. Left-handed individuals may develop aphasia handed individuals may develop aphasia after a lesion of either hemisphere after a lesion of either hemisphere

The neuroanatomic substrate of The neuroanatomic substrate of language comprehension and language comprehension and productionproduction• is complex, including auditory input is complex, including auditory input

and language decoding in the superior and language decoding in the superior temporal lobe, analysis in the parietal temporal lobe, analysis in the parietal lobe, and expression in the frontal lobe, lobe, and expression in the frontal lobe, descending via the corticobulbar tracts descending via the corticobulbar tracts to the internal capsule and brainstem, to the internal capsule and brainstem, with modulatory effects of the basal with modulatory effects of the basal ganglia and the cerebellum. ganglia and the cerebellum.

The entire language zone is perisylvian, it borders The entire language zone is perisylvian, it borders the sylvian fissurethe sylvian fissure

• 2 areas are 2 areas are receptivereceptive/ 2 areas are / 2 areas are executiveexecutive• The main receptive area – subserving the The main receptive area – subserving the

perception of spoken – posterosuperior perception of spoken – posterosuperior temporal area ( post. portion of area 22= temporal area ( post. portion of area 22= Wernicke area) and Heschl gyri (areas 41 and Wernicke area) and Heschl gyri (areas 41 and 42)42)

• The main executive or output region- in the The main executive or output region- in the posterior end of the inferior frontal convolution posterior end of the inferior frontal convolution (Brodmann areas 44 and 45)= Broca area(Brodmann areas 44 and 45)= Broca area

Classical aphasia Classical aphasia syndromessyndromes• Include – Total or Include – Total or global aphasiaglobal aphasia,,• Wernicke aphasia or sensoryWernicke aphasia or sensory= =

receptive/ posterior / fluent aphasiareceptive/ posterior / fluent aphasia• Broca aphasia or motorBroca aphasia or motor= expressive/ = expressive/

anterior/ nonfluent aphasiaanterior/ nonfluent aphasia

Disconnection language Disconnection language syndromessyndromes• = disorders of language that result not from a = disorders of language that result not from a

lesion of the cortical language areas lesion of the cortical language areas themselves but themselves but from an interruption of from an interruption of association pathwaysassociation pathways

• Conduction aphasiaConduction aphasia,,• AlexiaAlexia= visual verbal agnosia/ word blidness= visual verbal agnosia/ word blidness• as well as as well as transcortical motor, transcortical transcortical motor, transcortical

sensory, and transcortical mixed aphasiasensory, and transcortical mixed aphasia..

• Many specific aphasic syndromes have been reportedMany specific aphasic syndromes have been reported. . Classic nosology of the Classic nosology of the perisylvian aphasiasperisylvian aphasias includes includes

Broca, Wernicke, conduction, and global aphasias. Broca, Wernicke, conduction, and global aphasias. • The nonperisylvian aphasiasThe nonperisylvian aphasias include include anomic, transcortical motor, transcortical anomic, transcortical motor, transcortical

sensory, and mixed transcortical, sometimes called the sensory, and mixed transcortical, sometimes called the isolation of the speech area syndrome. isolation of the speech area syndrome.

Subcortical aphasia syndromes are defined more by the Subcortical aphasia syndromes are defined more by the anatomy of the lesion than by the language anatomy of the lesion than by the language characteristics. characteristics.

• Producing, receiving, and interpreting Producing, receiving, and interpreting speech requires specific and distinct speech requires specific and distinct cognitive processes such as phonologic cognitive processes such as phonologic decoding and encoding, orthographic decoding and encoding, orthographic decoding and encoding (for reading), decoding and encoding (for reading), lexical access, lexical-semantic lexical access, lexical-semantic representations of words, and semantic representations of words, and semantic interpretation of language. interpretation of language.

Bedside evaluation of languageBedside evaluation of language

• Each component of language should be tested individually Each component of language should be tested individually and thoroughly. Components of bedside language and thoroughly. Components of bedside language examination include examination include

assessments of assessments of spontaneous speech, naming, spontaneous speech, naming, repetition, comprehension, reading, and writingrepetition, comprehension, reading, and writing. .

• Spontaneous speechSpontaneous speech should be assessed for should be assessed for fluencyfluency (ease (ease and rapidity of producing words), and rapidity of producing words), amount of speechamount of speech (number (number of words produced), of words produced), initiation of speechinitiation of speech, the presence of , the presence of spontaneous spontaneous paraphasic errorsparaphasic errors (semantic or phonemic), (semantic or phonemic), word-finding pausesword-finding pauses, hesitations or circumlocutions, and , hesitations or circumlocutions, and prosody. prosody.

Semantic or verbal Semantic or verbal paraphasiasparaphasias are substitutions of are substitutions of incorrect words (eg, "fork" for "spoon"), whereas phonemic or incorrect words (eg, "fork" for "spoon"), whereas phonemic or literal paraphasias are substitution of incorrect sounds or literal paraphasias are substitution of incorrect sounds or phonemes (eg, "poon" for "spoon"). These aspects of phonemes (eg, "poon" for "spoon"). These aspects of expressive language are helpful in the diagnosis of aphasia.expressive language are helpful in the diagnosis of aphasia.

• Confrontation namingConfrontation naming is tested with is tested with several items involving several items involving objectsobjects (ring, (ring, pen, watch, glasses, paper clip), pen, watch, glasses, paper clip), object partsobject parts (watchband, winding (watchband, winding stem, crystal), stem, crystal), body partsbody parts (thumb, (thumb, palm of the hand, wrist, elbow), and palm of the hand, wrist, elbow), and colorscolors. .

• AssessmentAssessment should indicate should indicate repetition testingrepetition testing. . Abnormal repetitionAbnormal repetition is the hallmark of the is the hallmark of the perisylvian aphasiasperisylvian aphasias, the classic aphasias , the classic aphasias associated with lesions near the Sylvian fissure. associated with lesions near the Sylvian fissure. Perisylvian aphasias include Broca, Wernicke, Perisylvian aphasias include Broca, Wernicke, conduction, and global aphasias. conduction, and global aphasias.

• Preservation of repetition is a major distinguishing Preservation of repetition is a major distinguishing feature in nonperisylvian aphasias, including feature in nonperisylvian aphasias, including anomic aphasia, the transcortical aphasias, and anomic aphasia, the transcortical aphasias, and some subcortical or thalamic aphasias. some subcortical or thalamic aphasias.

Complete assessment of language production Complete assessment of language production should include oral and written modalitiesshould include oral and written modalities • ReadingReading should always be assessed as part of language should always be assessed as part of language

examination. Patients with alexia with agraphia examination. Patients with alexia with agraphia and alexia without agraphia and alexia without agraphia have different anatomic lesions,have different anatomic lesions, the former associated with left parietal the former associated with left parietal

lesions, lesions, the latter with left occipital lesions, usually the latter with left occipital lesions, usually

a stroke in the left posterior cerebral artery territory.a stroke in the left posterior cerebral artery territory. Spelling aloud, writing, and spelling words aloud to the patient Spelling aloud, writing, and spelling words aloud to the patient

are all preserved in patients with alexia without agraphia, but are all preserved in patients with alexia without agraphia, but not in alexia with agraphia. not in alexia with agraphia.

• WritingWriting should be assessed for quality, spelling, grammar, should be assessed for quality, spelling, grammar, and quantity, as well as for the accuracy of the productions. and quantity, as well as for the accuracy of the productions. In addition, patients should be tested for apraxiaIn addition, patients should be tested for apraxia

Global aphasiaGlobal aphasia

• the patient has deficits in the patient has deficits in all aspects of languageall aspects of language: : spontaneous speech, naming, repetition, auditory spontaneous speech, naming, repetition, auditory comprehension, reading, and writing comprehension, reading, and writing

• The deficits need not be total – can understand few words , The deficits need not be total – can understand few words , phrases emit only syllable, few words phrases emit only syllable, few words

• Global aphasia may result from strokes, tumors, dementia, or Global aphasia may result from strokes, tumors, dementia, or other causes. other causes.

• Global aphasia is commonly seen in patients with large Global aphasia is commonly seen in patients with large infarctions of the left cerebral hemisphere, typically involving infarctions of the left cerebral hemisphere, typically involving the occlusion of the internal carotid or middle cerebral artery the occlusion of the internal carotid or middle cerebral artery and resulting in a large, wedge-shaped infarction of the frontal, and resulting in a large, wedge-shaped infarction of the frontal, temporal, parietal, and deep portions of the middle cerebral temporal, parietal, and deep portions of the middle cerebral artery territory. Right hemiplegia (face and arm worse than the artery territory. Right hemiplegia (face and arm worse than the leg) is the rule, as is right homonymous hemianopsia.leg) is the rule, as is right homonymous hemianopsia.

Wernicke aphasiaWernicke aphasia• Two main elementsTwo main elements – – impairment of the comprehension of impairment of the comprehension of

speechspeech ( can execute simple comands, but there is a ( can execute simple comands, but there is a failure to carry out complex ones)failure to carry out complex ones)

+ + relatively fluent but paraphasic relatively fluent but paraphasic speechspeech

-their speech sounds empty and does not convey meaning. -their speech sounds empty and does not convey meaning. There may be fluent phrases without nouns and verbs, There may be fluent phrases without nouns and verbs, containing nonexistent word forms (neologisms). containing nonexistent word forms (neologisms).

The patient's speech and writing may include The patient's speech and writing may include paraphasic errors with sound substitutions (phonemic paraphasic errors with sound substitutions (phonemic paraphasias), word substitutions (semantic paraphasias), paraphasias), word substitutions (semantic paraphasias), hesitations, pauses, and circumlocutions. Grammar is hesitations, pauses, and circumlocutions. Grammar is better preserved than it is in Broca aphasia.better preserved than it is in Broca aphasia.

In its extreme, the fluent, paraphasic speech may be In its extreme, the fluent, paraphasic speech may be entirely incomprehensible (entirely incomprehensible (jargon aphasiajargon aphasia))

• Naming and repetition are typically impairedNaming and repetition are typically impaired. . • Although Although reading impairmentreading impairment often parallels the auditory often parallels the auditory

comprehension deficit, patients occasionally have preserved comprehension deficit, patients occasionally have preserved oral reading or even reading comprehension. This is oral reading or even reading comprehension. This is important in establishing communication with the patient.important in establishing communication with the patient.

• Written expression is abnormalWritten expression is abnormal; unlike patients with Broca ; unlike patients with Broca aphasia, these patients can write fluently, but their word aphasia, these patients can write fluently, but their word choice and spelling are usually very abnormal choice and spelling are usually very abnormal

• Patients with Wernicke aphasia are Patients with Wernicke aphasia are not always aware of their not always aware of their deficitsdeficits, and over time they may become frustrated that , and over time they may become frustrated that others do not understand them. others do not understand them.

• The lesion is variable but The lesion is variable but usually involves the posterior one-usually involves the posterior one-third of the superior temporal gyrus – near the primary third of the superior temporal gyrus – near the primary auditory cortexauditory cortex

Broca aphasiaBroca aphasia

• In the complete syndrome, patients present with - In the complete syndrome, patients present with - a nonfluent aphasiaa nonfluent aphasia. . They speak haltingly, without intonation, and have difficulty They speak haltingly, without intonation, and have difficulty

producing spontaneous speech, naming, and repeating. producing spontaneous speech, naming, and repeating.

Comprehension is relatively spared, Comprehension is relatively spared, though it is not normalthough it is not normal..

Phrases are short and may be telegraphic or Phrases are short and may be telegraphic or agrammaticagrammatic, including major , including major nouns and verbs but no functor words (articles, adjectives, adverbs, or nouns and verbs but no functor words (articles, adjectives, adverbs, or conjunctions). Patients have telegraphic speech, also called agrammatism. conjunctions). Patients have telegraphic speech, also called agrammatism. Naming of actionsNaming of actions is typically worse than naming of objects. is typically worse than naming of objects.

• A A writing deficitwriting deficit usually parallels the phonologic deficit. usually parallels the phonologic deficit.• Repetition is abnormalRepetition is abnormal and often consists of omission of functor words. and often consists of omission of functor words.

• Typically, the lesions in Broca aphasia are localized to the dorsolateral Typically, the lesions in Broca aphasia are localized to the dorsolateral frontal cortex (the posterior two thirds of the inferior frontal gyrus frontal cortex (the posterior two thirds of the inferior frontal gyrus operculum)operculum)

Pure alexia without agraphiaPure alexia without agraphia

• Pure alexia is known by a variety of names, including alexia without Pure alexia is known by a variety of names, including alexia without agraphia, posterior alexia, and literal or letter-by-letter alexia. Patients with agraphia, posterior alexia, and literal or letter-by-letter alexia. Patients with pure alexia have normal expressive speech, normal naming (except in pure alexia have normal expressive speech, normal naming (except in some cases for color anomia or inability to name colors), normal repetition, some cases for color anomia or inability to name colors), normal repetition, normal auditory comprehension, and even normal ability to write. Their normal auditory comprehension, and even normal ability to write. Their alexia is a relatively pure deficit. Patients may be able to write a sentence, alexia is a relatively pure deficit. Patients may be able to write a sentence, then be unable to read it. They have no difficulty spelling aloud and no then be unable to read it. They have no difficulty spelling aloud and no difficulty in recognizing words spelled to them aloud or spelled in tactile difficulty in recognizing words spelled to them aloud or spelled in tactile fashion on the palm of the hand. Patients may be able to read individual fashion on the palm of the hand. Patients may be able to read individual letters, then laboriously piece them together and say the words (letter-by-letters, then laboriously piece them together and say the words (letter-by-letter alexia). letter alexia).

• Neighborhood signs useful in the diagnosis of pure alexia include a Neighborhood signs useful in the diagnosis of pure alexia include a contralateral (right) superior quadrantanopsia or hemianopia and color contralateral (right) superior quadrantanopsia or hemianopia and color anomia. anomia. The syndrome is almost always associated with a stroke in the The syndrome is almost always associated with a stroke in the territory of the left posterior cerebral artery. The lesion may also involve territory of the left posterior cerebral artery. The lesion may also involve the splenium of the corpus callosum and the medial temporal lobethe splenium of the corpus callosum and the medial temporal lobe. .

• Dejerine first described this syndrome in 1892, postulating a disconnection Dejerine first described this syndrome in 1892, postulating a disconnection between the right occipital cortex (and intact left visual field) and the left between the right occipital cortex (and intact left visual field) and the left hemisphere language area, such that visual information cannot be decoded hemisphere language area, such that visual information cannot be decoded into language in the left hemisphere.into language in the left hemisphere.

• Alexia is the acquired inability to read.• In isolated alexia (alexia without agraphia),

thepatient cannot recognize entire words or readthem quickly, but can decipher them letter byletter, and can understand verbally spelledwords. The ability to write is unaffected. • The responsible lesion is typically in the left

temporooccipital region with involvement of the visual pathway and of callosal fibers.

Alexia with agraphiaAlexia with agraphia

• Alexia with agraphia is also known as the Alexia with agraphia is also known as the angular gyrus syndromeangular gyrus syndrome and central alexia. It is, in effect, an acquired illiteracy; patients lose and central alexia. It is, in effect, an acquired illiteracy; patients lose their previously acquired reading and writing skills. Most lose spelling their previously acquired reading and writing skills. Most lose spelling and the ability to understand words spelled to them. Many patients and the ability to understand words spelled to them. Many patients have fluent, paraphasic speech, unlike the preserved speech of pure have fluent, paraphasic speech, unlike the preserved speech of pure alexia without agraphia, but auditory comprehension is much superior alexia without agraphia, but auditory comprehension is much superior to reading comprehension. to reading comprehension.

• The lesion usually involves the angular gyrus area in the left inferior The lesion usually involves the angular gyrus area in the left inferior parietal lobule. This syndrome was also described by Dejerineparietal lobule. This syndrome was also described by Dejerine. .

• Closely related to the pure alexia with agraphia syndrome is the Closely related to the pure alexia with agraphia syndrome is the Gerstmann syndromeGerstmann syndrome.. Gerstmann brought together the 4 deficits of Gerstmann brought together the 4 deficits of agraphia, acalculia, right-left confusion, and finger agnosia and agraphia, acalculia, right-left confusion, and finger agnosia and associated them with lesions of the associated them with lesions of the dominant parietal lobedominant parietal lobe. Alexia, . Alexia, though not originally a cardinal feature of the Gerstmann syndrome, though not originally a cardinal feature of the Gerstmann syndrome, is often associated. is often associated.

AGRAPHIAAGRAPHIA

• Pure agraphia is a great rarityPure agraphia is a great rarity Agraphia is the acquired inability to write.

Agraphia may be isolated (due to a lesionlocated in area 6, the superior parietal lobule, orelsewhere) or accompanied by other disturbances.• TC exam disclose a TC exam disclose a lesion of the posterior lesion of the posterior

perisylvian area - a lesion in or near the angularperisylvian area - a lesion in or near the angular gyrus will occasionally cause a disproportionate gyrus will occasionally cause a disproportionate disorder of writing as a disorder of writing as a part of Gerstmann syndrpart of Gerstmann syndr..

Right hemisphere contributions to languageRight hemisphere contributions to language

• are numerous are numerous → → right hemisphere functions right hemisphere functions related to communication. related to communication.

• include the comprehension of metaphor, include the comprehension of metaphor, sarcasm, and humor, as well as the sarcasm, and humor, as well as the emotional emotional prosody of speech, ie, the extralinguistic prosody of speech, ie, the extralinguistic aspects of human communication. aspects of human communication.

• Patients with right hemisphere lesions may Patients with right hemisphere lesions may understand words but fail to understand the understand words but fail to understand the emotional context of a conversation or the emotional context of a conversation or the facial expressions and tones of voice that facial expressions and tones of voice that convey meaning in normal communication convey meaning in normal communication

ANARTHRIAANARTHRIA

• In pure dysarthria or anarthria there is no In pure dysarthria or anarthria there is no abnormality of the cortical language mechanismabnormality of the cortical language mechanism

• The patient – is able to The patient – is able to understand perfectlyunderstand perfectly what what is heardis heard

- has no difficulty in writing and - has no difficulty in writing and readingreading

- unable to utter a single intelligible - unable to utter a single intelligible wordword

When the dominant frontal operculum is damagedWhen the dominant frontal operculum is damaged

APRAXIAAPRAXIA

Liepmann introduce the term in 1900Liepmann introduce the term in 1900

from the from the GreekGreek root word root word praxispraxis, for an act, work, for an act, work • = a state in which an attentive = a state in which an attentive

patient loses the ability to execute patient loses the ability to execute previously learned activities in the previously learned activities in the absence of weakness, ataxia, sensory absence of weakness, ataxia, sensory loss, or extrapyramidal derangementloss, or extrapyramidal derangement

• Patients are not paretic but have lost Patients are not paretic but have lost information about how to perform information about how to perform skilled movements. skilled movements.

• Apraxia has a neurologic cause that Apraxia has a neurologic cause that localizeslocalizes fairly well to the fairly well to the leftleft inferior inferior parietal lobule, the frontal lobes parietal lobule, the frontal lobes (especially the premotor cortex, (especially the premotor cortex, supplementary motor area, and supplementary motor area, and convexity), or the corpus callosumconvexity), or the corpus callosum. .

• Any disease of these areas can cause Any disease of these areas can cause apraxia, although stroke and dementia are apraxia, although stroke and dementia are the most common causes the most common causes

Types of ApraxiaTypes of Apraxia

• There is no consensus on There is no consensus on how to dividehow to divide and organize and organize the many different syndromes classified as apraxia. the many different syndromes classified as apraxia. Authors have divided apraxias based on the following:Authors have divided apraxias based on the following:

Body part affectedBody part affected ( limb apraxia or buccofacial ( limb apraxia or buccofacial apraxia)apraxia)

Dysfunctional sensory areaDysfunctional sensory area (left inferior parietal) (left inferior parietal) or or motor areasmotor areas (left premotor and left supplementary (left premotor and left supplementary motor)motor)

If use of tools is affectedIf use of tools is affected (transitive vs (transitive vs intransitive)intransitive)

Deficits in pantomiming tool use and Deficits in pantomiming tool use and gesture gesture (ideomotor apraxia)(ideomotor apraxia)

If knowledge about the use of tools is If knowledge about the use of tools is preserved (preserved (conceptual or ideational apraxia)conceptual or ideational apraxia)

• Conceptual apraxiaConceptual apraxia = = a loss of knowledge about tools a loss of knowledge about tools and the movements associated with their use.and the movements associated with their use.

• Patients with Patients with parietal lesionsparietal lesions may have this condition. may have this condition. ≠ ≠

These individuals can be contrasted with patients with These individuals can be contrasted with patients with supplementary motor area (SMA) lesions or other supplementary motor area (SMA) lesions or other lesions of the premotor cortex. lesions of the premotor cortex.

Patients in the latter group would have Patients in the latter group would have normal knowledge about how to move but would be normal knowledge about how to move but would be unable to perform the movement correctly because of unable to perform the movement correctly because of faulty transcoding of the "innervatory patterns" in the faulty transcoding of the "innervatory patterns" in the motor cortex.motor cortex.

• ApraxiaApraxia has been divided into three types has been divided into three types IDEATIONALIDEATIONAL IDEOMOTORIDEOMOTOR KINETICKINETIC

• Apraxia like syndromesApraxia like syndromes DRESSING APRAXIADRESSING APRAXIA CONSTRUCTIONAL APRAXIACONSTRUCTIONAL APRAXIA

EtiologyEtiology• Apraxia is a syndrome reflecting motor system Apraxia is a syndrome reflecting motor system

dysfunction at the dysfunction at the corticalcortical level, exclusive of the level, exclusive of the primary motor cortexprimary motor cortex..

• Normally, in Normally, in planningplanning movements, previously movements, previously learned, stored complex representations of skilled learned, stored complex representations of skilled movements are used. These 3D, supramodal movements are used. These 3D, supramodal codes, also called representations or movement codes, also called representations or movement formulae, are stored formulae, are stored in the inferior parietal lobule in the inferior parietal lobule of the left hemisphereof the left hemisphere. .

• Diseases that involve this part of the brain, Diseases that involve this part of the brain, including strokes, dementias, and tumors, can including strokes, dementias, and tumors, can cause loss of knowledge about how to perform cause loss of knowledge about how to perform skilled movements.skilled movements.

Apraxia can occur with lesions in other locations as well.Apraxia can occur with lesions in other locations as well.

• Information contained in praxis representations isInformation contained in praxis representations is transcoded into innervatory patternstranscoded into innervatory patterns by the by the premotor corticespremotor cortices, including the , including the

SMA and possibly the convexity of the premotor SMA and possibly the convexity of the premotor cortex. cortex.

The information is then The information is then transmittedtransmitted to the to the primary primary motor cortexmotor cortex, and a movement is , and a movement is performedperformed..

Lesions of the SMA or other premotor cortices also can cause Lesions of the SMA or other premotor cortices also can cause apraxia; in this case, knowledge about movement is still present, apraxia; in this case, knowledge about movement is still present, but the ability to perform movement is absent. but the ability to perform movement is absent.

Apraxia also occurs with lesions of Apraxia also occurs with lesions of the corpus callosumthe corpus callosum, such as , such as tumors or anterior cerebral artery strokes.tumors or anterior cerebral artery strokes.

• Although the corpus callosum is not Although the corpus callosum is not known to be involved directly in the known to be involved directly in the performance of skilled movements, it performance of skilled movements, it contains fibers crossing from the right contains fibers crossing from the right hemisphere to the premotor cortex. hemisphere to the premotor cortex. This type of apraxia represents a This type of apraxia represents a classic disconnection syndrome; classic disconnection syndrome; patients with callosal apraxia typically patients with callosal apraxia typically are apractic only with the left handare apractic only with the left hand

Anatomic and functional imaging data indicateAnatomic and functional imaging data indicate

• Planned or commanded actionPlanned or commanded action – developed in – developed in the parietal lobe of the language dominant the parietal lobe of the language dominant hemispherehemisphere, where visual, auditory and , where visual, auditory and somesthetic information is integrated – A somesthetic information is integrated – A “space-time plan” depends on the integrity of “space-time plan” depends on the integrity of the dominant parietal lobethe dominant parietal lobe

The failure to conceive or to formulate an The failure to conceive or to formulate an action, either spontaneously or to command= action, either spontaneously or to command=

IDEATIONAL APRAXIAIDEATIONAL APRAXIA difficulty in difficulty in “ what to do”“ what to do”

• is impairment of the ability to carry out complex, learned, goal-directed activities in proper logical sequence.

• A temporal or parietal lesion may be responsible. Examination:

• The patient is asked to carry out pantomimicgestures such as opening a letter, making asandwich, or preparing a cup of tea.

• Ideational/conceptual Ideational/conceptual apraxiaapraxia: Patients have : Patients have an an inability to conceptualize a task andinability to conceptualize a task and

• impaired ability to complete multistep impaired ability to complete multistep actions.actions. Consists of an Consists of an inability to select and inability to select and carry outcarry out an appropriate an appropriate motor programmotor program..

• For example, the patient may complete For example, the patient may complete actions in incorrect actions in incorrect ordersorders, such as buttering bread before putting it in the , such as buttering bread before putting it in the toaster, or putting on shoes before putting on socks. toaster, or putting on shoes before putting on socks.

• There is also a loss of ability to voluntarily perform a learned There is also a loss of ability to voluntarily perform a learned task when given the necessary objects or toolstask when given the necessary objects or tools. For instance, . For instance, if given a screwdriver, the patient may try to write with it as if if given a screwdriver, the patient may try to write with it as if it were a pen, or try to comb one's hair with a toothbrushit were a pen, or try to comb one's hair with a toothbrush

• Sensory areas 5 and 7 in the dominant parietal lobe Sensory areas 5 and 7 in the dominant parietal lobe are connected with are connected with the supplementary and premotor the supplementary and premotor cortices of both cerebral hemispherescortices of both cerebral hemispheres and their and their integral connections are involved as an ensemble to integral connections are involved as an ensemble to accomplish these actions-accomplish these actions-

these areas or their connections are interrupted – these areas or their connections are interrupted – IDEOMOTOR APRAXIAIDEOMOTOR APRAXIA

=the patient may know and remember the planned =the patient may know and remember the planned action but he cannot execute it with either handaction but he cannot execute it with either hand

block in block in “ how to do”“ how to do” inability to transmit the gesture to executive inability to transmit the gesture to executive

motor centersmotor centers

• involves the faulty execution(parapraxia) of acquired voluntary and complex movement sequences;

• it can be demonstrated most clearly by asking the patient to perform pantomimic gestures.

• Examination (pantomimic gestures on command): face (openeyes, stick out tongue, lick lips, blow out amatch, pucker, suck on a straw); arms (turn ascrew, cut paper, throw ball, comb hair, brushteeth, snap fingers); legs (kick ball, stamp outcigarette, climb stairs). The patient may perform the movement in incorrect

sequence, or may carry out a movement of the wrong type (e. g.,puffing instead of sucking).

• IdeomotorIdeomotor apraxiaapraxia: These patients have deficits in : These patients have deficits in their ability to plan or complete motor actions that their ability to plan or complete motor actions that rely on rely on semantic memorysemantic memory. .

• They are They are able to explain how to perform an actionable to explain how to perform an action, , but but unable to "imagine" or act out unable to "imagine" or act out a movementa movement such as "pretend to brush your teeth" such as "pretend to brush your teeth" or "pucker as though you bit into a sour lemon." or "pucker as though you bit into a sour lemon."

• The ability to perform an action automatically The ability to perform an action automatically when cued, however, remains intactwhen cued, however, remains intact. This is known . This is known as automatic-voluntary dissociation. For example as automatic-voluntary dissociation. For example they may not be able to pick up a phone when they may not be able to pick up a phone when asked to do so, but can perform the action without asked to do so, but can perform the action without thinking when the phone ringsthinking when the phone rings

LIMB- KINETIC APRAXIALIMB- KINETIC APRAXIA

• means a clumsy hand.means a clumsy hand. Typically, it refers to the inability to make Typically, it refers to the inability to make

precise movements with the limb, precise movements with the limb, especially the fingers contralateral to a especially the fingers contralateral to a brain injury. For example, patients may brain injury. For example, patients may not be able to make rapid finger not be able to make rapid finger movements, to grasp objects in a pincer movements, to grasp objects in a pincer fashion, or to perform tapping fashion, or to perform tapping movements. movements.

Manifestations of of non-dominant parietal Manifestations of of non-dominant parietal lobe diseaselobe disease• DRESSING APRAXIADRESSING APRAXIAis often seen in patients with nondominantparietal lobe lesions. They cannot dress themselves and do not

know how to position a shirt,shoes, trousers, or other items of clothing to put them on correctly.

An underlying impairment of spatial orientation is responsible.

Constructional apraxiaConstructional apraxia refers to the inability to draw or copy refers to the inability to draw or copy

quality pictures, such as interlocking quality pictures, such as interlocking pentagons, or complex figures, such pentagons, or complex figures, such as the Rey-Osterreith figure. as the Rey-Osterreith figure. Constructional apraxia can localize Constructional apraxia can localize damagedamage to several brain regions, to several brain regions, including the frontal or left or right including the frontal or left or right parietal area. parietal area.