MSC Neuro 2025 P1
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Striatalhyperkinesias=toomanymovements(chorea,athetosis,tics)
PallidalParkinsonism=toofewmovements(bradykinesia,rigidity,tremor)
31.Internalcapsule. Syndromesoftherightinnercapsule.
InternalCapsule–Anatomy&Syndromes
Anatomy(whitematterconduit)
Location:Betweenlentiformnucleus(lateral)andcaudatehead+ thalamus(medial).
Parts:
1.Anteriorlimb–frontopontine+thalamocorticalfibers.
2.Genu(knee)–corticobulbar(corticonuclear)fibers.
3.Posteriorlimb:
Anterior2/3: corticospinaltract→pyramidaltract.
Posterior1/3:sensory(thalamocortical)+opticradiation(Gratiolet’s bundle).
SyndromesofLesion(RightInternalCapsuleexample)
1.AnteriorLimb
Lossoffrontopontinefibers→frontalataxia(astasia–abasia:can’tstandorwalk despitepreservedstrength).
2.Genu(Knee)
Corticobulbarfibers→contralateralcranialsigns:
Facialweakness(lower ½face)
Tongueweakness(deviation)→ centralparesis.
3.PosteriorLimb
Pyramidaltractlesion(anterior2/3posteriorlimb):
Contralateralhemiplegia(spastic:↑tone,↑reflexes,pathologicalreflexes).
“Capsularhemiplegia”=dense,complete(face+arm+leg).
TypicalWernicke–Mann posture:
Armflexedandadductedtotrunk.
Legextended,withcircumductiongait.
Footexternally rotatedonparalysedside.
Thalamocorticalsensoryfibers(posterior1/3):
Contralateralhemianesthesia(allmodalities).
Geniculocalcarinefibers(optic radiation,Gratiolet’sbundle):
Contralateralhomonymoushemianopia.
Retainedpupillightreaction(distinguishfromoccipital corticallesion).
Sometimescentralfieldloss(scotomas).
ClinicalPictureofaMajorInternalCapsuleStroke(e.g.RightIC)
Lefthemiplegia(spastic)with Wernicke–Mannposture.
Lefthemianesthesia.
Lefthomonymoushemianopia(ifposteriorradiationinvolved).
Centralfacialparesis+tongue weakness(contralateral).
Hallmark:Densecontralateralhemiplegia+hemianesthesia+hemianopia =“ThreeH Syndrome”ofinternalcapsule.
ExamPearl:
Capsularstrokeproduces maximalneurologicaldeficitwithminimallesion→ because fibersdenselypacked.
ICLesion=Contralateralspastichemiplegia,hemianesthesia,hemianopia+central CNpalsy.
32.Higherbrainfunctionsandtheir disorders:apraxias, types,clinicalcharacteristics
33.Higherbrainfunctionsandtheir disorders: aphasias,types,clinicsphysical characteristics.
34.Higherbrainfunctionsandtheir disorders:agnosia,types,clinicalcharacteristics. HigherBrainFunctions andTheirDisorders
Highercorticalfunctions=Speech,Gnosis (recognition),Praxis(purposefulacts),Memory (mnesticfunctions).
1.Speechdisorders→Aphasia
Definition:Loss/impairmentofpreviouslyacquiredspeech(NOTduetoparalysis,hearing loss,ordysarthria).
TypesofAphasia
Motor(Broca’s)aphasia–frontallobe(inferiorfrontalgyrus,dominanthemisphere)
Patientunderstandsspeechbutcannotarticulatewell.
Speech=non-fluent,agrammatic,e ortful.
Sensory(Wernicke’s)aphasia–superiortemporalgyrus(dominanthemisphere)
Patientspeaksfluently butspeechismeaningless("wordsalad").
Poorcomprehension.
Subtypes:
Acoustic-gnostic:cannotdi erentiatesounds/words.
Acoustic-mnestic:impairedwordmemory,cannotnameobjects thoughdescriptionisintact.
Conductionaphasia–lesionofarcuatefasciculus(disconnectionBroca↔ Wernicke).
Repetitionimpaired,otherwise relativelypreserved.
Alexia&Agraphia–lossofreading/writingability(parietallobeinvolvement).
2.Gnosisdisorders→Agnosia
Definition:Impairmentinrecognition,despiteintactvision,hearing,orsensation.
TypesofAgnosia
Visualagnosia–occipitallobedamage.
Candescribeobject(shape/size/color)butcannotname/recognizeit visually.Recognition intactiftouched.
Auditoryagnosia–temporallobe damage.
Normalhearing,butcannotrecognizefamiliarsounds/words/music.
Tactileagnosia(Astereognosis)–parietallobelesion.
Cannotrecognizeobjectsbytouchwithintactsensation.
Autotopagnosia–cannotrecognizepartsofone’sownbody.
Anosognosia–lack ofawarenessofone’sillness(commoninrightparietalstroke).
Spatialagnosia–disorientation,cannotfindwayinfamiliarplaces.
3.Praxisdisorders→Apraxia
Definition:Inabilitytoperformpurposefullearnedacts,despitenormalstrength,tone, coordination,and comprehension.
Types:
Ideomotorapraxia–cannotperform command-basedgestures(e.g.,salute,wave goodbye),thoughunderstandscommand.
Ideationalapraxia–cannotperform multi-steptasks(buttoning, dressing,making tea).
Buccofacialapraxia–cannotimitatefacial/oralmovements.
Constructionalapraxia–cannotconstruct/drawobjects(parietaldamage).
4.Memorydisorders→ Amnesia
Fixationamnesia –inabilitytoregisternewinformation;oldmemoryrelatively preserved.
Korsako ’s syndrome –fixationamnesia+disorientation(commoninalcoholism, B1deficiency).
Retrogradeamnesia– lossofmemoryforperiodbeforeinsult.
Anterogradeamnesia–cannotcreatenewmemoriesafterinsult.
AdditionalCognitiveDisorders
Dementia:Global,progressivelossofacquiredintellectualfunction (Alzheimer’s, vasculardementia).
Oligophrenia:Global,non-progressivecognitiveimpairmentpresentfromchildhood (congenital/genetic/earlydevelopmental).
SummarybyLobe(importantforexams)
Lobe |
ClinicalSyndromes |
|
Motoraphasia(Broca’s),Apraxia,Jacksonianmotorepilepsy,Gaze |
Frontal |
paresis,Personality/psychechanges |
|
Sensoryhemiataxia,Mono/hemianesthesia,Astereognosis, |
Parietal |
Anosognosia,Apraxiatypes,Alexia, Acalculia |
Sensoryaphasia(Wernicke’s),Auditoryagnosia,Memoryloss, Hallucinations(auditory,olfactory,gustatory), Temporallobe
Temporal epilepsy
Visualagnosia,Hemianopia,Visualhallucinations,
Occipital Metamorphopsias(micropsia, macropsia),Photopsias
ExamPearls:
Aphasia→languagedisorder.
Agnosia→recognitiondisorder.
Apraxia→purposefulmotoractdisorder.
Amnesia→memorydisorder.
Astereognosis=tactileagnosia(can’trecognize bytouch).
Anosognosia=deniesillness(oftenrightparietalstroke).
Wernicke’s=fluentbutmeaningless, Broca’s =nonfluent,e ortful.
35.Methodologyforthestudyofhigherbrainfunctions.
Methodology fortheStudyofHigherBrainFunctions
Higherfunctions=Speech,Gnosis,Praxis,Memory,Attention,Intelligence
I.StudyofSpeech
Checkifdisorderis aphasia(cortical),dysarthria(motor),dyslalia(articulation),or mutism(psychogenic).
Approach
1.Assessspontaneousspeech
Fluency?Grammar?Wordchoice? Paraphasias,neologisms?
2.Motor(Broca’s)aphasia
Patientunderstandsbutcannotexpresswell→speaksinshort,agrammatic phrasesorsinglewords.
3.Sensory(Wernicke’s)aphasia
Fluentbutmeaningless;doesn’tunderstand addressedspeech; paraphasias.
4.Globalaphasia
Bothproductionandcomprehensionimpaired.
5.Tasks
Followcommands(“closeeyes,showtongue”).
Complexinstructions(“touchwithleftindexfingeryourrightear”).
Understandingofmetaphors/proverbs.
6.Writing(Agraphia):askpatienttowriteaphrase (free,fromdictation,copy).
7.Reading(Alexia):ask patienttoreadtextaloudandexplain.
II.StudyofGnosis(Recognition)
Gnosis=abilitytorecognizeandinterpretsensoryinput. Testeachmodality:
1.Visualagnosia–showfamiliarobject(key,pen).Candescribebutcannotname.→ (occipitallesion).
2.Auditoryagnosia–producesounds(clap,waterrunning,bell).Patientmustidentify sound.→(temporallesion).
3.Tactileagnosia(Astereognosis)–patientcloseseyes;placeobjectinhand(coin, key).Ifcannotidentify→parietallesion.
4.Specialforms:
Anosognosia–denialofillness(oftenrightparietalstroke).
Autotopagnosia–failuretorecognizeone’sbodyparts.
III.StudyofPraxis(PurposefulActions)
Praxis=abilitytoperformlearned,coordinatedactions.
Apraxia=lossofskilledmovementsnotduetoweakness,sensoryloss,orataxia.
Testing
1.Imitationofsimpleactions–combinghair,brushingteeth,threadinganeedle.
2.Symbolicmovements– salute,wavegoodbye.
3.Sequentialtest–“fist→ edge→palm”(askpatienttorepeatsequence).
4.Constructivepraxis– ask patientto:
Assemblepuzzle/structure.
Drawshapes(cube,clock,house).
IV.StudyofMemory
Short-term/fixation:recall3wordsafter5min.
Long-term:recallpersonalhistory,recentevents.
Korsako ’sSyndrome: impairedfixationmemory,confabulations.
V.Attention
Askpatienttocountbackward,recitemonths ofyearin reverse,serial7 subtractions.
Notedistractibility,perseveration.
VI.Intelligence
Orientation:time,place,person.
Abstractthinking:explainmetaphors,proverbs.
Problem-solving: similarities/di erences(“howare anappleandorangealike?”).
Dementiasuspectedwithimpairedjudgment,memory,orientation,abstract thought.
SummaryTable
Function |
Test |
Disorderifimpaired |
|
Conversation,commands, |
Aphasia(Broca,Wernicke, |
Speech |
reading/writing |
global,conduction) |
|
|
Agnosia(visual,auditory, |
|
Showobjects,playsounds, |
tactile,anosognosia, |
Gnosis |
tactilerecognition |
autotopagnosia) |
|
Imitation,symbolicacts, |
|
|
“fist–edge–palm”, |
Apraxia(ideomotor, ideational, |
Praxis |
constructiontasks |
constructional) |
Memory |
Recallwords/events |
Amnesia,Korsako ’s |
|
Countingbackwards,serial |
|
Attention |
7s |
Distractibility,reducedspan |
|
Orientation,proverbs, |
|
Intelligence |
similarities |
Dementia, oligophrenia |
ExamPearls
Alwaysexclude aphonia/dysarthriabeforediagnosingaphasia.
Keymnemonics:Aphasia=speech,Agnosia=recognition,Apraxia=action, Amnesia=memory.
Lobecorrelation:frontal(motor+ praxis),parietal(gnosis),temporal(memory, Wernicke),occipital(visualgnosis).
36.Alternatingparalysiswithdamagetothebridgeofthebrain(pons).
I.AlternatingParalysisinthePons
1.Miyar–GublerSyndrome
Lesion:base oflowerpons
Signs:
Ipsilateral:peripheralfacialparalysis(CNVIInucleus/nerve)
Contralateral: hemiplegia(corticospinaltract)
2.FauvilleSyndrome
Lesion:lowerpons
Signs:
Ipsilateral:peripheralCN VIIpalsy+lateralrectus palsy(CNVI)→ internalstrabismus
Contralateral: hemiplegia
3.GasperiniSyndrome
Lesion:pontineoperculum
Signs:
Ipsilateral:CNVIIpalsy,hearingloss,trigeminalhypoesthesia
Contralateral: sensoryloss(hemianesthesia)
4.Raymond–SestanSyndrome
Lesion:pons(centerofgaze+MLF+middlepeduncle +pyramids)
Signs: gaze palsy,MLFlesion,cerebellarataxia+contralateralhemiparesis
5.Brissot–Sicard
IrritationofCNVIInucleus
Ipsilateralfacialspasm+contralateralhemiparesis
37.Alternatingparalysiswithdamagetothemidbrain.
1.Weber’sSyndrome
Lesion:cerebralpeduncle
Ipsilateral:CNIIIpalsy(ptosis,exotropia,mydriasis)
Contralateral: hemiplegia(face+limbs,centraltype)
2.Benedikt’sSyndrome
Lesion:rednucleus+CNIIIfibers
Ipsilateral:CNIIIpalsy
Contralateral: intentiontremor,choreoathetosis(rednucleus,cerebellar pathways)
3.Claude’sSyndrome
Lesion:CNIII+red nucleus+cerebellartracts
Ipsilateral:CNIIIpalsy
Contralateral: cerebellarataxia,hypotonia
4.Notnagel’sSyndrome
Lesion:tectal/midbrainroof+CNIII
Ipsilateral:CNIIIpalsy
Contralateral: cerebellarataxia;sometimesdeafness,hyperkinesias
5.Foville/Fua’sSyndrome(variantsreported)
CNIIIpalsy+contralateralchoreoathetosis,tremor,sensorydisturbances.
38.Alternatingparalysisinlesionsofthemedullaoblongata.
1.Jackson’sSyndrome
Lesion:CNXIInucleus+pyramidaltract
Ipsilateral:tonguepalsy(LMN →deviatestowardlesion,atrophy, fasciculations)
Contralateral: hemiparesis
2.Avellis’Syndrome
Lesion:CNIX&Xnuclei+corticospinaltract
Ipsilateral:dysphonia,dysarthria,dysphagia(palate,larynx,pharynx)
Contralateral: hemiparesis/hemianesthesia
3.Schmidt’sSyndrome
Lesion:CNIX–X–XI–XII+ pyramidaltract
Ipsilateral:bulbarpalsy+SCM/trapeziuspalsy(droopingshoulder)
Contralateral: hemiparesis
4.Babinski–NageotteSyndrome
Lesion:dorsolateralmedulla(PICAinfarct)
Ipsilateral:cerebellarataxia,Horner’ssyndrome,cranialnerveinvolvement
Contralateral: sensoryloss(pain/temp)—“crossedsensorydeficits”