disorders of lobes

7/23/2019 Disorders of Lobes

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Narkeesh

M.P.T (Neuro)

SBSPGI


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Dysfunction or disease of the cerebral hemispheres

can be organic (ie, of known structural, chemical, or

metabolic mechanism) or nonorganic (of unknown

cause). The latter includes the major psychoses and

many behavioral disorders.


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The cerebrum (supratentorial or front of brain) - composed

of the right and left hemispheres.

unctions ! initiation of movement, coordination of

movement, temperature, touch, vision, hearing, judgment,

reasoning, problem solving, emotions, and learning.

"rodmann # divided into $% areas

&erebral corte' # layers

The frontal corte' # dominated by pyramidal rather than

granular. # *granular corte'+

The parietal corte' # dominated by granular layers #

ranular corte'+


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30% of cerebrum

Area 4, 6, 8 & 44-motor activity Area 4-primary motor cortex- directlyconnected with omatoenory neuron ofthe anterior part of pot central !yru &alo parietal, thalamic and red nucleiand reticular formation of the braintem" Area 8 #turnin! the head and eye tocontralaterally"

Area 44 # dominant hemiphere $brocaarea # lip ton!ue pharynx larynx # bilatleion caue paralyi of phonation,articulation and de!lutition"


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'he medial-orbital !yri and ant part ofcin!ulated !yri which are the frontal

component of limbic ytem- ta(e part incontrol of repiration, blood preure,peritali, and autonomic function"

'he mot ant part # )-*+ and 4-4-prefrontal area-dei!nated function-initiation of planned action and executivecontrol of all mental operation includin!emotional expreion

.yramidal cell at area 4 & 6

/lood upply # AA and 1up div of 2A


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C/F

motor abnorSpeech and language disorders

Impairment of cognitive function

Akinesia & lack of initiative and spontaneity (apathy

& abulia)

changes in personality change in mood and self

controlincontinence of bladder and bo!el


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Motor Abnormalities

posterior part - spastic paralysis of the contralateral

face, arm and leg.anterior and medial parts of the motor cortex -(area 6& supplementary motor area of 8 the premotorcortex) results in less paralysis and more spasticity as

well as a release of sucking, & grasping reflexesroca!s area - loss of motor speech, agraphia, andapraxia of the face, lips and tongue

"esions of motor parts - #uadriplegia$paresis-will %eseere and affecting the cranial neres as well asspine


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Motor Abnormalities (cont.)

Gait Disorder

medial !art o" "rontal lobe # connections

$ith basal %an%lion& then $eakness& loss o"

sensation& incoordination $ith cerebellum

results in %ait disorders.

" f li h fl i


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"osture of slight fle#ion

$urning !ith one foot

%ifficulty in stepping

unable to move his feet for!ard

feet !ere glued to the floor (slipping Clutch)

unable to stand and to sit

difficulty in turn over in bed(Cerebral paraplegia in fle#ion)


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/ncontinence inolement of posterior part of sup.'rontal and ant. ingulate gyri & interening white

matter result in loss of control of micturition anddefecation.(no warning of fullness of %ladder)

0peech and 1anguage! "roca2s *phasia

laconic speech (concise)

1ack of spontaneity of speech

telegraphic speech (agrammatism)

1oss of fluency (verbal stereotypes)

3erseveration of speech

tendency to whisper instead of speaking aloud

dysarthria


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&ognitive and /ntellectual &hanges

organ of &ivili4ation+

&hanged personalities

Decreased initiative

1ack of concern (relation)

reedom of an'iety

Difficulty in problem solving

rontal lobe memory defect will be general

disturbance in thinking

1oss of volition (willing)


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3roblem solving proceeds in four steps(perceptual,

constructive, arithmetical and logical)

5. specification of a problem

%. a plan of action for the solution of the problem

6. e'ecution, including implementation and

control of the plan

7. checking or comparison of the results against

the original plan


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Summary of Frontal lobe disease

I'ffects of unilateral frontal disease

aContralateral spastic hemiplegia

b Slight elevation of mood increased talkativenesstendency to oke lack of tact difficulty in adaptation

loss of initiativec it entirely prefrontalno hemiplegia* grasp and

suck refle#es may be released

d Anosmia (loss of sense of smell) !ith involvement

of orbital parts

II 'ffects of right frontal disease

a +eft ,emiplegia

b changes in I b c and d


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Summary of Frontal lobe disease (cont-)

III 'ffects of left frontal disease

a.ight ,emiplegia

b otor speech disorder !ith agraphia !ith or

!ithout apra#ia of the lips and tongue

c loss of verbal associative fluency* preservation

d changes as in Ib c and d


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Summary of Frontal lobe disease (cont.)

I0 'ffect of bifrontal diseasea 1ilateral hemiplegia

b spastic bulbar palsy

c If prefrontal abulia(!ill po!er) or akinetic

mutism lack of ability to sustain attention and

solve comple# problems rigidity of thinking

behavioral disinhibition inability to anticipate

labile mood decomposition of gait and sphintericincontinence


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there is no definite anatomical boundary between

the temporal lobe and the occipital or parietal lobe

the sylvian fissure separates the superior surface

of each temporal lobe from the frontal and anterior

part of parietal lobe

the temporal lobe includes!

0uperior, middle and inferior temporal

1ateral occipitotemporalusiform

1ingual

3arahippocampal and hippocampal


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Disorders of temporal lobe divided into

disorders of special senses

time perception

language

memory

emotion

behaviour


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8isual Disorders

lesion of white matter of the central and posterior

part of temporal characteristically involve the lower archingfibres of the geniculocalcarine pathway # this results in

upper homonomous 9uadrantanopia

the middle (area %5) and inferior (area 6:) temporal

gyri receive a massive fibres from the striate corte' (area5:) and parastriate visual (area 5; and 5


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&ortical Deafness

1ocali4ation of primary auditory corte' (area 75 and 7%) in

the transverse gyri # lesions in this area results in

deafness= effect on hearing

*uditory agnosia

lesions in the secondary corte' # area %% and partof %5 results in perception of combinations of sound is

impaired.

auditory agnosia # takes several forms - inability to

recogni4e sounds and differrent musical notes (amusia)

appreciation of music is impaired by nondominant

temporal lobe


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*uditory 8erbal *gnosia

- >ernicke2s aphasia

- left temporal lobe fails in its function of

decoding the acoustic signals of speech and converting

them into appropriate e'pressions.

*uditory illusions

- sounds are perceived more loudly or less loudly

than normal (paracusia)

- words may seem strange or disagreeable


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*uditory allucinations

- murmurs, blowing, sound of running water,whistles, sirens

8estibular Disturbance

- 0uperior and posterior part of temporal(posterior to the primary auditory corte')

- inducing vertigo

- sense of dise9uilibrium

Time 3erception

- seem to stand still or to pass with great speed

- repeatedly look at the clock


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0mell and Taste

- medial part of temporal lobe

- gustatory and olfactory hallucinations

Disorders of emory, emotion and behavior

- retentive memory

- hyper se'uality


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Summary of $emporal lobe disease

I 'ffects of unilateral disease of the dominant lobe

a ,omonymous upper 2uadrantanopia

b 3ernicke4s aphasia

c Amusia (loss of ability to recogni5e music)

d Impairments in tests of verbal materialpresented through the auditory sense

e amnesic aphasia

f 0isual agnosia


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Summary of $emporal lobe disease (cont)

II 'ffects of unilateral disease of the nondominant lobe

a ,omonymous upper 2uadrantanopia

b Inability to udge spatial relationships

c Agnosia for sounds and musics

III 'ffects of disease of either lobe

a auditory visual olfactory and gustatoryhallucinations

b %reamy states !ith unicinate sei5ures

c 'motional and behavioral changes

d %elirium


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Summary of $emporal lobe disease (cont-)

I0 'ffects of bilateral disease

a 6orsakoff amnesic defect (hippocampal formation)(unable to place event in their proper timerelationship)

b apathy and placidityc increased se#ual activity

d 7Sham rage8

?luver "ucy 0yndrome


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*reas in the 3arietal 1obe play a role in somatosensory

processes.

*reas 6, %, and 5 are located on the primary sensory

strip, - primary sensory areas for touch andkinesthesia.

*reas $, :, and 7@ - posterior to the primary sensory

strip and correspond to the presensory to sensoryassociation areas.

*rea 6< - angular gyrus.


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Parietal lobes # t$o "unctional re%ions

' # sensation and !erce!tion (cognition).

# sensor in!ut& !rimaril $ith the *isual

sstem. (a spatial coordinatesystem to represent

the world around us)


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8isual Disorders

Deep to the inferior part of parietal

- involving geniculocalcarine radiations

- results in homonomous hemianopia

3osterior parietal lesion

- defect in locali4ation of visual stimuli

- inability to compare the si4es of objects

- failure to avoid objects when walking

- inability to count objects

- striking disorder of motor behavior of eyelids


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&ortical sensory syndrome

- friendship between thalamus and sensory corte'

3seudo thalamic syndrome

- burning pain (identical to thalamic pain

syndrome)

- resulted from vascular lesions restricted to

corte'

3seudo cerebellar syndrome

- hypotonia

- incoordination of movement

- intention tremor


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8erger-Dejerine 0yndrome

- loss of position sense

- astereognosis

- impairment in two point descrimination

- impairment to recogni4e figures written on the

skin

3arietal sensory deficit

- inconsistency of response to painful stimuli

- difficulty in distinguishing more than one contact

at a time

- occurrence of hallucination of touch


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*somatognosias

- perception of one2s own body and of the relation

of bodily parts to one another- depends upon the visual and labyrinythine

impulses

Anilateral asomatognosia(*nton "abinski 0yndrome)

- anosognosia(asked to raise the paraly4ed arm,

patient will raise the intact arm)

- pt may fail to shave one side

- fail to apply lipstick or comb the hair on one side

- impossible to wear eyeglasses

- dressing on one side


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"ilateral *somatognosia

BerstmannCs 0yndrome+ ight-left confusion

*graphia

*calculia = Dyscalculia

*phasia

*gnosia

/deomotor and ideational apra'ia


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Summary of "arietal lobe disease

I 'ffects of unilateraldisease of the parietal lobe

a Cortical senory syndrome (total hemianaesthesia!ith large acute lesions of !hite matter)

b mild hemiparesis unilateral muscular atrophy in

children hypotonia poverty of movementhemiata#ia

c homonomous hemianopia visual inattentionanosognosia neglect of one half of the body


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Summary of "arietal lobe disease (cont-)

II 'ffects of unilateraldisease of the dominantlobe

a disorders of language

b 9erstmann syndrome

c tactile agnosiad 1ilateral ideational and ideamotor apra#ia

Summary of "arietal lobe disease (cont )


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Summary of "arietal lobe disease (cont-)

III 'ffects of unilat disease of nondominantlobe

a 0isual spatial disorders

b $opographic memory loss

c Anosognosia and dressing apra#ia

d Confusion

e $endency to keep the eyes closed & resist toopening

I0 'ffects of 1ilateraldisease

a 0isual spatial imperceptions optic ata#ia spatialdisorientation and severe forms of constructionalapra#ia


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The Eccipital 1obe contains areas that process visualstimuli.

*rea 5: is the primary visual area.

*reas 5; and 5< are the secondary visual areas.

"ut appro'imately %@ other visual areas, but not well

defined

The /sland of eil or /nsula is a cortical area which

lies below the fissure of 0ylvius and is considered by

some anatomists to be the fifth lobe of the cerebrum.

/t can only be seen by splitting the lateral fissure


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8isual ield Defects

- homonomous hemianopia

- emiachromatopsia (loss of color vision)

- bilateral lesion result in bilateral central

hemianopia

&ortical "lindness

- loss of sight

- loss of refle' closure of eye lids to a bright light

- cause # occlusion of 3&*

- ecovery stage- complaints of visual fatigue,

difficulties in fi'ation and fusion


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8isual *nosognosia (*nton syndrome)

- blindness # act like normal

- can see small objects - act like blind

8isual illusions (metamorphosias)

- fail to arouse visual memories

- icropsia (seems too small)

- acropsia (seems too large)

- inverted vision

- *chromatopsia (disappearance of color)

- erythropsia (illusion coloring)

- polyopia (appearing as two or more)

8isual allucinations (sensory as well as cognitive)


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8isual allucinations(sensory as well as cognitive)

- flashes of light - colors

- stars - multiple lights

- geometric forms

lesion indication of visual associative area

8isual agnosia- Ebject agnosia

- simultagnosia

- "alint syndrome (hand eye incoordination)

- 3rospognosia (face /D)

- 8isual disorientation

- color agnosia


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*amage to thesu%corticalstructures results toehaioral and ognitie distur%ance

*ominant thalamiclesions results in *ysphagia and

*yspraxia

+mygdalais importance in %ehaior if %ilateraldamage to the amygdalae results in

distur%ance of memory as well as social %ehaior impaired recognition of emotional facialrecognition

f l l l


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*isease of asal gangliaresults in prominent cognitieand conatie dysfunction ilateral halamicinfarcts results in distur%ance of

attentionight thalamic infarcts results in left eglect syndrome

audate lesionsare commonly with %ehaioraldistur%ances, usually a%ulia than with motor syndromes

*ominant head of caudate infarcts resultsin dysphagiawith dysarthria and orofacial dyspraxia.

ilateral infarction of head of caudate had resulted in

seerely aggressie and criminal %ehaior


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References

Snells Neuro Anatomy

Poddars Anatomy of Central Nerous System

Adams Princi!les of Neurolo"y

#indsays Clinical Neurolo"y

$ilroys %asic Neurolo"y

%rains &iseases of t'e Nerous system

o'n Pattern Neurolo"ical &ifferential &ia"nosis


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disorders of lobes

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