HIGHER COGNITIVE FUNCTIONS

INTRODUCTION

• Attention,language and memory serves as the building blocks for higher intelectual functions.

• Higher cognitive functions are manipulation of well learned matiriel ,abstract thinking, problem solving, arithematic computations.

• Above functions are the highest level intellectual functions often the earliest markers of cortical dysfunction.

• These can be readily assesed by carefully history taking about his job performance, management of finances, problem solving and over all judgement.

• Behaviour : • a. the aggregate of all the responses made by

an organism in any situation• b. a specific response of a certain organism to

a specific stimulus or group of stimuli• c. the action, reaction, or functioning of a

system, under normal or specified circumstances

• Personality :• The pattern of collective character, behavioral,

temperamental, emotional and mental traits of a person.

EVALUATION

• Categorised in the following groups:– Fund of acquired information.– Manipulation of old knowledge.– Social awareness and judgement.– Abstract thinking.

• Fund of information is acomplished by simple verbal tests of vocabulary, general information and comprehension.

• Manipulation of old knowledge is tested by social comprehension and caluculation.

• Abstract thinking is a more complex function assesed by proverb interpretation, conceptual or anology interpretation.

Fund of information

• A series of 10 questions are asked in order of increasing difficulty till the patient unable to answer 3 succesive questions or test is completed.

• If the patients answer is unclear should be asked to explain again.

• Examiner can repeat the question but should not paraphase or spell or explain words.

Table of questionsHow many weeks are there in a year

52

Why do people have lungs ? respiration

Name three prime ministers of india whom you remember

appropriate answer

Where is culcutta West bengal

How far is Tirupathi to vijayawada

400 to 500km

Why light colored clothes cooler than dark ones in summer

Appropriate answer

What is capital of pakisthan islamabad

What causes rust Appropriate answer

Who wrote ramayana valmiki

Why is Tajmahal constructed Appropriate answer

• Scoring– Average patient should answer minimum of six

questions.– Less adequate performance indicate reduced

inteligence, limited social and education exposure or significant dementia.

– Stable over a wide age range.– Impaired early in alzeimers disease.

• Caliculations are complex neuropsychologic testing that requires distinct components of number sense and manipulation.– Rote tables(addition, substraction and

multiplication)– Basic arithmatic concepts(carrying and borrowing)– Recognition of signs.– Correct spatial alignment of written caliculation.

• Verbal note examples:

– Read each example in a clear voice and record patients response.

1. Addition : 4+6=10, 7+9=16

2. Substraction : 8-5=3, 17-9=8

3. Multiplication : 28=16, 97=63

4. Division : 9/3 = 3, 56/8 =7

• Verbal complex examples:

– Allow only 20 sec for a response.– Failure to respond in time –considered as a failure

Addition : 24+26=50, 27+49=76

Substraction : 18-15=3, 17-9=8

Multiplication : 258= 200

Division : 128/8 = 16

• Written complex examples:

– Allow sufficient time to respond( 30 sec)– If patient is inattentive , try using individual cards for each sum.– Failure to complete each task should be noted(even after time).– Record errors in alignment as well.

Addition : 124+526,

Substraction : 218-75

Multiplication : 10838

Division : 559/43

PROVERB INTERPRETATION:• Directions : proverbs are presented in

ascending order of difficulty .– The instructor should tell the patient that I am

going tell you a saying you may or may not have heard explain in your own words what that means.

• Scoring:– abstract-2, semiabstract-1,concrete-0.– Total of ten points.

• Test items: 1. Don’t cry over spilled milk2. Rome wasn't built in a day3. A drowning man will clutch at straw4. Golden hammer can break down an iron door5. Hot coal burns ,the cold one blackens

• A total score of less than 5 is significant.

• Simalarities :– Requires analysis of relationships, formation of

verbal concept and logical thinking.• Directions: tell the patient that I am going to

tell some pairs of objects .each pair is alike in some way. Please tell me how they are alike.

• Test items:– Turnip-cauliflower.– Car-airplane.– desk-book case.– Poem-novel.– Horse-apple.

• Non retarded patient with a normal educational status should obtain a score of 5 or 6 in this test.

• Equal impairment on this and fund of informations suggests educational deprivati on rather than specific deficit in abstract thinking.

• INSIGHT AND JUDGEMENT:Insight is once ability to understand oneself or

external situation.Judgement is a complex mantal process where by a

person forms a opinion makes a decision or plan action or respond after analyzing the issue and comparing choices with acceptable social behaviour.

• ANATOMY:– Higher cortical function rely on intact cerebral

cortex though subcortical lesions can effect performance.

– Except for caliculating ability these functions are not localised particular area.

– Abstract thinking is widely represented in cortical and subcortical areas

– Social judgement is affected in frontal lobe lesions.

– Verbal reasoning and abstraction are primarily dominent hemisphere lesions because of close relation ship with language.

– Left hemispheric lesions show more severe impairment of caliculation.

– Malalighnment of numbers in complex caliculations is a feature of right parietal lobe lesion.

• CLINICAL IMPLICATIONS :– Testing for higher cognitive functions helps in

detection of early disease because these are affected well before the basic aminities of language , attention, memory.

– Results of the tests depends upon educational status and social ex posure of the patient.

• Results to be compared with patients social judgement and history of family members and patients performance in day today events for arriving at accurate diagnosis.

RELATED COGNITIVE FUNCTIONS

• Apraxia and visual agnosia which were previously classified along with aphasias and higher cortical functions now cosidere seperately as related cognitive functions.

• apraxia is ahigh level motor disturbance.• Visual agnosia is a high level perceptual

disturbance.

• APRAXIA:–An acquired disorder learned skilled

sequential motor events that can not be accounted for elementary disturbances in strength, coordination, sensation, or lack of comprehension or attention.–Defect in motor planning.

• IDEOMOTOR APRAXIA:– Most common type of apraxia.– Patient fails to perform a previously learned motor

act accurately.• Buccofacial apraxia.• Limb apraxia.• Truncal apraxia.

• EVALUATION:– Hiararchy of difficulty in performing the motor

task.– 1 st step most difficult perform a action on verbal

command.– 2 nd step performing the action and asked to

immitate.– 3 rd step provide actual object and ask him to

follow thecommand.

CLINICAL IMPLICATIONS

• IDEATIONAL APRAXIA:– Also known as conceptual apraxia.– Disturbance in complex motor planning of higher

order.– Difficulty in performing a task having a series of

different but related steps.– Examples : postal envolope, ligting a candle,

placing tooth paste over tooth brush.

• Clinical implications:– Patients with ideational apraxia have elements of

ideomotor apraxia, constructional impairment and spatial orientation.

– Associated with wide spread intellectual seen in patients of dementia.

• VISUAL OBJECT AGNOSIA:– Failure to recognize objects by vision with

preserved ability to recognize them through touch or hearing and in the absence of impaired primary visual perception or dementia.

• Apperceptive visual agnosia:– Perceived elements of object are synthesized to

whole image.– Pick out features of the object correctly such as

lines, angles,colors or movement but fail to appreciate the whole object.

– Examples : spectacles, forest.– Right hemisphere particularly lingual gyrus

involved in global processing of the object.

• Left hemisphere occipital cortex invoved in more local processing.

• ASSOCIATED VISUAL AGNOSIA:– Is more closely related to than primary disorder of

vision.– Patients can copy and match the drawing of

objects but can not name them.– They can be identified by tactile or auditary

modality.– have associated color agnosia and prosagnosia.

– Bilateral posterior hemispheric lesions involving occipitotemporal gyrus some times lingual gyri and adjacent white matter.

• Charecterised by– Simultagnosia is a disorder of visual attention

especially to peripheral field associated inability to perform orderly visual scanning of the environment and attention to other sensory stimuli are intact.

– Optic ataxia is the loss of hand eye co-ordination with difficulty in touching or reaching the objects under visual guidance.

BALINT SYNDROME

– Optic apraxia is inability project gaze voluntarily in the peripheral field despite intact occulomotor movements.

BALINT SYNDROME

GERSTMANN SYNDROME

• Charesteristic features:– Dyscaliculia.– Dysgraphia.– Finger agnosia [ in ability to point out, recognize

and name fingers of one self or others ]– Right-left confusion [ inability to distinguish right

left of one self or others ]

Gerstmann syndrome