Behavioral NeurologyBehavioral Neurology

Behavioral NeurologyBehavioral Neurology(Cognitive and Behavioral Neurology)(Cognitive and Behavioral Neurology)

- is dealing with disorders of higher nervous functions resulting from structural brain damage (directed attention, mood, gnostic functions, cognitive functions, memory, …)

- investigates a relationship between brain and behavior, between brain and mind

- relatively young, interdisciplinary field of study – neurology, psychiatry, neuropsychology

- in the past BN dealt mainly with dementias and aphasias, currently BN is rather focused on frontal and temporal lobe syndromes, consciousness (awareness) and attention, agnosias, and many other aspects of HNF.

Phineas Gage• 1848, New England1848, New England• PG, 25 years, efficient and faithful foreman on the railPG, 25 years, efficient and faithful foreman on the railroadroad

construction through Vermont.construction through Vermont.• When preparing the rock shooting PG mistakenly ram down powder When preparing the rock shooting PG mistakenly ram down powder

and detonator with iron rod (needful sand was missing). and detonator with iron rod (needful sand was missing). • During the explosion the iron rod (length 1 m, diameter 4 cm, 6 kg) During the explosion the iron rod (length 1 m, diameter 4 cm, 6 kg)

threw open Gagethrew open Gage’’s left cheek, bashed in the base skull, passed over s left cheek, bashed in the base skull, passed over the ventral part of the brain and catapulted through crown of the the ventral part of the brain and catapulted through crown of the head.head.

• Personality changePersonality change: „he started to be volatile, impolite, time to time : „he started to be volatile, impolite, time to time he was extremely foul-mouthed and stubborn“. For incredibility he he was extremely foul-mouthed and stubborn“. For incredibility he lost a good job, rotated with many work places (incl. career in lost a good job, rotated with many work places (incl. career in circus), he became an alcoholic and desperate. The neurological circus), he became an alcoholic and desperate. The neurological status was otherwise normal.status was otherwise normal.

• He died in 38 years because of status epilepticus.He died in 38 years because of status epilepticus.

H. Damasio, 1992

Patient H.M.• Intractable temporal lobe epilepsy from the age of 16 yrsIntractable temporal lobe epilepsy from the age of 16 yrs

• 1953 – W. Scoville – 1953 – W. Scoville – bilateral resection of mesiotemporal regionsbilateral resection of mesiotemporal regions..

• Postoperatively Postoperatively persisted serious anterograde amnesiapersisted serious anterograde amnesia (impairment of (impairment of storage)storage)

Examination of mental functions

• It should be a requisite part of standard neurologic examination – at least Mini Mental State Examination should be performed in neurologic pts.

• It has to be systematic and hierarchic (level of consciousness directed attention cognition, mood, speech)

• Golden neurologic rule „to localize a lesion“ should be applied for mental functions too (neuronal networks).

• Extremely important is thorough history taking (changes in

pt’s behavior) and focusing on the pt’s behavior during the examination (evaluation of his/her appearance, cooperation, attention, memory, mental flexibility, social adaptability, ability of nonverbal communication, depressive symptomatology, etc.).

Bedside tests of attention

• Luria (fist-palm-side) test

• Luria sketch (visual completion test) (alternating square and pointed figs.)

• Continuous performance test

After registering target digit in presented digit chain a subject has to knock on a table

4-9-1-7-5-4-0-7-9-2-4-3-7-5-0-2

• Digit span test (3-7) – subject has to learn and repeat long digit chains, also test on short-term memory

Large-scale neural network for directed attention (Mesulam MM)

Neglect syndromeNeglect syndrome

= a failure to report, respond, or orient to contralateral novel = a failure to report, respond, or orient to contralateral novel stimuli that is caused by damage of large-scale neural stimuli that is caused by damage of large-scale neural network for directed attention and not by an elemental network for directed attention and not by an elemental sensorimotor deficit. sensorimotor deficit.

It is a form of It is a form of selective unawarenessselective unawareness. .

Pts with neglect syndrome often appears to be unaware of Pts with neglect syndrome often appears to be unaware of contralateral stimuli, they ignore these items, and do not contralateral stimuli, they ignore these items, and do not react to them.react to them.

Within neglect there can be Within neglect there can be hemiakinesiahemiakinesia ( (motor neglect = motor neglect = movement deficiencymovement deficiency = pseudohemiparesis = pseudohemiparesis), ), anosognosiaanosognosia and/or and/or anosodiaforiaanosodiaforia (absence of concomitant emotions for (absence of concomitant emotions for serious functional deficit).serious functional deficit).

Bedside memory testing is limited episodic m.

(autobiographic data)

long-term m. (> 1 min)

Explicite memory semantic m. (declarative) (encyclopedic knowledge)

(visual x verbal, recall x recognition) short-term (working) m. (30-40 s) (digit span)

procedural m. (completing word fragment, m. for movements)

Implicit memory demonstrated by completion priming of tasks that do not requireconscious processing= the ability to acquire a motor skills or cognitive routines by experience

(mesiotemporal regions– hipp,entorh, perirh, GP)

(more extensive reg. – MT+LT,P,O)

(DLPFC + associative visual and auditory areas)

(subcortical circuits – BG, cerebellum + ctx visual, motor,..)

F

H O S P - - - -

Disorders of symbolic functions

Dysphasia - disorders of speech (Motor or expressive /Broca΄s/ dysphasia; Sensory or receptive /Wernicke΄s/ dysphasia; Global dysphasia). DOMINANT HEMISPHERE

Aprosodia – impairment of affective component of speech (speech melody, intonation, voice timbre, use of pauses, etc.) řečově nedominantní hemisféra). NON-DOMINANT HEMISPHERE

Dressing apraxia - difficulties in dressing, e.g. Getting arm into pyjamas, …

Constructional apraxia – innability to copy geometrical pattern

Alexia - disturbance of reading (angular or lingual g. within dominant hemisphere).

Agraphia - disturbance of writing (GFM or PO junction of the dominant hemisphere).

Acalculia - disturbance of calculation (dominant hemisphere, also within the Gerstmann΄s syndrome – angular g.).

GnosisGnosis – greek „cognition“ – greek „cognition“

• Gnostic function = an ability to know (recognize) individual objectsGnostic function = an ability to know (recognize) individual objects

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AGNOSIA (without recognition) – def. = impaired recognition of an object which is AGNOSIA (without recognition) – def. = impaired recognition of an object which is sensorially presented while at the same time the impairment cannot be reduced to sensorially presented while at the same time the impairment cannot be reduced to sensory defects (intact primary sensory cortex), mental deterioration, sensory defects (intact primary sensory cortex), mental deterioration, disorders ofdisorders of consciousness and consciousness and attentionattention, or to a non-familiarity with the object., or to a non-familiarity with the object.

The term The term agnosiaagnosia is from S. Freud (1891) is from S. Freud (1891) Finkelnburg 1870 – „Finkelnburg 1870 – „asymboliaasymbolia““Jackson 1876 – „Jackson 1876 – „imperceptionimperception““Munk 1881 – „Munk 1881 – „seelenblindheitseelenblindheit“(mind blindness) /X cortical blindness/ “(mind blindness) /X cortical blindness/

Affected individuals behave as seeing (…) the object for the first time in their life.Affected individuals behave as seeing (…) the object for the first time in their life.

Beware of erroneous diagnosis of agnosias!Beware of erroneous diagnosis of agnosias!- darkness or very - darkness or very rapidrapid object presentation object presentation- unfamiliar objects (e.g. tuning fork) - unfamiliar objects (e.g. tuning fork) - insufficient instructions - insufficient instructions - overlooking another disease (polyneuropathy, cataract, - overlooking another disease (polyneuropathy, cataract, otosclerosis,…) otosclerosis,…) - aphasic phenomena- aphasic phenomena- apraxic phenomena - apraxic phenomena

Agnosias are related to the lesions within associative cortices and their Agnosias are related to the lesions within associative cortices and their very surrounding but also with disconnections (impairment of the very surrounding but also with disconnections (impairment of the corpus callosum or long fibers within the white matter).corpus callosum or long fibers within the white matter).

Unfortunately in the practice agnosias are often associated with other Unfortunately in the practice agnosias are often associated with other neurologic deficits (aphasia, apraxia, behavioral disorder)! Resulting neurologic deficits (aphasia, apraxia, behavioral disorder)! Resulting clinical manifestation is therefore highly individual.clinical manifestation is therefore highly individual.

Visual agnosiaVisual agnosiaSpecific impairment of recognition of visually presented objects – pt is well seeing but he/she is Specific impairment of recognition of visually presented objects – pt is well seeing but he/she is not able to identify these items. not able to identify these items.

Clinical classification according to the character of impairment:Clinical classification according to the character of impairment:

Apperceptive visual agnosia – Apperceptive visual agnosia – patient is neither able to recognize objects patient is neither able to recognize objects visually nor their form, and is not able to describe it correctly.visually nor their form, and is not able to describe it correctly.

Associative visual agnosia – Associative visual agnosia – patient is not able to recognize objects but patient is not able to recognize objects but he/she can describe the form or even is able to draw the object correctly.he/she can describe the form or even is able to draw the object correctly.

According to the type of affected stimuli:According to the type of affected stimuli:

- - Agnosia for objectsAgnosia for objects - - Agnosia for colorsAgnosia for colors - - AkinetopsiaAkinetopsia- - ProsopagnosiaProsopagnosia- - SimultanagnosiaSimultanagnosia - - Pure alexiaPure alexia

- …..- …..

- - Agnosia for objectsAgnosia for objects (by definition pts are not able to recognize objects when they (by definition pts are not able to recognize objects when they are solely presented visually. Usually visual object agnosia was considered as the are solely presented visually. Usually visual object agnosia was considered as the classical example of agnosias, but frankly it is very rare type of visual agnosia. The classical example of agnosias, but frankly it is very rare type of visual agnosia. The most frequently it arises from bilateral (rarely just left-sided) damage of lateral parts most frequently it arises from bilateral (rarely just left-sided) damage of lateral parts of occipital lobes (strokes).of occipital lobes (strokes).

- - Agnosia for colorsAgnosia for colors (coloragnosia) – the loss of ability to recognize colors as an (coloragnosia) – the loss of ability to recognize colors as an aaccquired disorder. Pt is unable to recognize colors, but he/she understands colors quired disorder. Pt is unable to recognize colors, but he/she understands colors and is able to correctly name e.g. the color of banana, orange, etc. (lesion within left and is able to correctly name e.g. the color of banana, orange, etc. (lesion within left occipital lobe – prestriatal cortex – ventral visual stream). It needs to be occipital lobe – prestriatal cortex – ventral visual stream). It needs to be differentiated from from inability to name colors!differentiated from from inability to name colors!- - Hemiagnosia for colorsHemiagnosia for colors – the inability to recognize colors confined to one half of – the inability to recognize colors confined to one half of the visual field – maybe attention defect (similarly to “unilateral spatial agnosia“)? the visual field – maybe attention defect (similarly to “unilateral spatial agnosia“)?

- - AkinetopsiaAkinetopsia – selective impairment of visual perception of motion („motion – selective impairment of visual perception of motion („motion blindness“), whilst there is a normal recognition of colors or object forms. Lesion blindness“), whilst there is a normal recognition of colors or object forms. Lesion within extrastriatal cortex (dorsal stream, lateral TPO region).within extrastriatal cortex (dorsal stream, lateral TPO region).

- - ProsopagnosiaProsopagnosia (not as rare as visual object agnosia) – loss of ability to recogni (not as rare as visual object agnosia) – loss of ability to recognizze e familiar faces. It can be highly specific (for human faces, for own face, for animal familiar faces. It can be highly specific (for human faces, for own face, for animal faces). Most often there is a lesion within right-sided occipitotemporal or faces). Most often there is a lesion within right-sided occipitotemporal or parietooccipital cortical regions (ventral stream).parietooccipital cortical regions (ventral stream).

Auditory agnosiaAuditory agnosia Very rare, usually is resulting from the lesion within the left-sided lateral temporal neocortex. Very rare, usually is resulting from the lesion within the left-sided lateral temporal neocortex.

– – Auditory agnosia for non-linguistic soundsAuditory agnosia for non-linguistic sounds (“psychic deafness“) (“psychic deafness“) (the inability (the inability to recognize concrete sounds as animal noises, the sound of a stream of water, of a to recognize concrete sounds as animal noises, the sound of a stream of water, of a sounding bell, of a ticking of a clock, etc.)sounding bell, of a ticking of a clock, etc.)

- - PhonagnosiaPhonagnosia (auditory analog of prosopagnosia)(auditory analog of prosopagnosia) – impairment of voice recognition and – impairment of voice recognition and discrimination; the inability to recognize familiar voice (lesion in lower and lateral discrimination; the inability to recognize familiar voice (lesion in lower and lateral parts of the right parietal lobe) and to discriminate between unfamiliar voices parts of the right parietal lobe) and to discriminate between unfamiliar voices (impairment of the temporal lobes independently of the side). De facto 2 anatomical (impairment of the temporal lobes independently of the side). De facto 2 anatomical systems – 2 distinct clinical syndromes. systems – 2 distinct clinical syndromes. - - Sensory amusiaSensory amusia – the inability to recognize music, melody or rhythms (lesion – the inability to recognize music, melody or rhythms (lesion within the non-dominant hemisphere)within the non-dominant hemisphere)

Tactile agnosiaTactile agnosia = astereognosia = astereognosia

A condition in which objects tactually are not recognized. The sensation had to be A condition in which objects tactually are not recognized. The sensation had to be intact. intact.

Primary astereognosiaPrimary astereognosia – patient is neither able to tactually recognize objects – patient is neither able to tactually recognize objects nor their forms or materials from which they are made.nor their forms or materials from which they are made.

Secondary astereognosiaSecondary astereognosia – Patient does not recognize tactually objects but – Patient does not recognize tactually objects but he/she recognizes well the form, size or material.he/she recognizes well the form, size or material.

The most commonly lesion can be found within the parietal lobe behind the The most commonly lesion can be found within the parietal lobe behind the postcentral gyrus (incl. supramarginal gyrus ). The disorder can be observed in postcentral gyrus (incl. supramarginal gyrus ). The disorder can be observed in lesions within both dominant and non-dominant hemispheres. lesions within both dominant and non-dominant hemispheres.

Multisensorial agnosiasMultisensorial agnosias very rarevery rare

Disorders of somatognosiaDisorders of somatognosia - impairments of the recognition of the body scheme.- impairments of the recognition of the body scheme.

- - AutotopagnosiaAutotopagnosia – patient does not recognize parts of his/her own body. Disorder – patient does not recognize parts of his/her own body. Disorder is not related to the dominant/non-dominant hemisphere, it results from impairment is not related to the dominant/non-dominant hemisphere, it results from impairment of contralateral parietal lobe.of contralateral parietal lobe.- - HemisomatagnosiaHemisomatagnosia

- - Finger agnosiaFinger agnosia – – difficulty in distinguishing fdifficulty in distinguishing fingersingers on hand on hand (this condition can be (this condition can be seen in Gerstmannseen in Gerstmann΄́ss syndrome). syndrome).

- - Mirror asomatognosiaMirror asomatognosia – mirror-induced disorders of the body image. Right-sided – mirror-induced disorders of the body image. Right-sided lesions. lesions.

- - Agnosia of painAgnosia of pain – pain asymbolia (Schilder-Stengel syndrome) – emotional – pain asymbolia (Schilder-Stengel syndrome) – emotional reactions to the pain are absent in the patient. Disorder is caused by the dysfunction reactions to the pain are absent in the patient. Disorder is caused by the dysfunction of parietal lobe.of parietal lobe.

AnosognosiaAnosognosia

– inability tp recognise and to understand own physical disability (especially motor deficit - – inability tp recognise and to understand own physical disability (especially motor deficit - hemiplegia) that is actually denying by the patient. Typically anosognosia can be seen in pts hemiplegia) that is actually denying by the patient. Typically anosognosia can be seen in pts

with left-sided hemiplegia. with left-sided hemiplegia. In fact the In fact the awarenessawareness of own deficit is lacking = of own deficit is lacking = disorder of focused attentiondisorder of focused attention! !

AntonAnton’’s syndromes syndromesimultaneous occurrence of cortical blindness and anosognosia (pt denies truthfull loss of simultaneous occurrence of cortical blindness and anosognosia (pt denies truthfull loss of

vision)vision)

Neglect syndrome Neglect syndrome – unilateral spatial agnosia– unilateral spatial agnosia

attentional hemideficit = selective unawareness of contralateral stimuli. Practically attentional hemideficit = selective unawareness of contralateral stimuli. Practically ppts with neglect syndromets with neglect syndrome “ignore“ “ignore“ contralateral stimuli and do not react to them. contralateral stimuli and do not react to them.

Within neglect Within neglect also also there canthere can be be hemiakinesiahemiakinesia (movement deficiency) and/or (movement deficiency) and/or anosodiaforiaanosodiaforia (absence of concomitant emotions for serious functional deficit). (absence of concomitant emotions for serious functional deficit).

– – damage of large-scale cortico-subcortical neurocognitive network for directed damage of large-scale cortico-subcortical neurocognitive network for directed attention (right-sided inferior parietal lobule, right-sided prefrontal and orbitofrontal attention (right-sided inferior parietal lobule, right-sided prefrontal and orbitofrontal

cortex, right-sided thalamus and basal ganglia)cortex, right-sided thalamus and basal ganglia)

- Unconscious perception in neglect syndromeUnconscious perception in neglect syndromeThere is increasing evidence that some pts with neglect may covertly perceive the contralateral stimuli and that There is increasing evidence that some pts with neglect may covertly perceive the contralateral stimuli and that

may at least partially react to these stimuli may at least partially react to these stimuli (Volpe et al. 1979; Berti et al. 1992; Wallace 1994)(Volpe et al. 1979; Berti et al. 1992; Wallace 1994)

- - Covert recognition of faces in prosopagnosiaCovert recognition of faces in prosopagnosia In some cases of prosopagnosia, there has been a dramatic dissociation between the loss of face recognition In some cases of prosopagnosia, there has been a dramatic dissociation between the loss of face recognition ability on the one hand, and the apparently preserved ability to recognize facability on the one hand, and the apparently preserved ability to recognize facees, when that is assessed indirectly s, when that is assessed indirectly – skin resistance (Bauer 1984; Bruyer 1992; DeHaan et al. 1987, 1992), ERP (Renault et al. 1989)– skin resistance (Bauer 1984; Bruyer 1992; DeHaan et al. 1987, 1992), ERP (Renault et al. 1989)

- - Implicit shape perception in apperceptive visual agnosiaImplicit shape perception in apperceptive visual agnosia- - Implicit object identification in associative visual agnosiaImplicit object identification in associative visual agnosia (Taylor and Warrington 1971; Goodale et al. 1991; Jankowiak et al. 1992; Farah and Feinberg 1997) (Taylor and Warrington 1971; Goodale et al. 1991; Jankowiak et al. 1992; Farah and Feinberg 1997)

- - BlindsightBlindsight – the best known syndrome – preserved ability of some patients to respond to certain aspects of – the best known syndrome – preserved ability of some patients to respond to certain aspects of visual stimuli in the areas of their visual fields that are blind on conventional clinical testing (lesions of prim. visual stimuli in the areas of their visual fields that are blind on conventional clinical testing (lesions of prim. visual cortex). visual cortex). (Riddoch 1917; Weiskrantz et al. 1974, 1977, 1996, 1998; Perenin 1987; Ptito et al. 1991; Stoerig (Riddoch 1917; Weiskrantz et al. 1974, 1977, 1996, 1998; Perenin 1987; Ptito et al. 1991; Stoerig and Cowey 1992; Tomaiuolo et al. 1997; Sahraie et al. 1997; Zeki and ffytche 1998) and Cowey 1992; Tomaiuolo et al. 1997; Sahraie et al. 1997; Zeki and ffytche 1998)

- - Inverse AntonInverse Anton’’s syndromes syndrome - - pt. with spared central island of vision denies visual sensation and he/she pt. with spared central island of vision denies visual sensation and he/she is behaving as the blind = selective impairment of awareness for visual stimuli in complete visual field (covert is behaving as the blind = selective impairment of awareness for visual stimuli in complete visual field (covert vision). (Walsh and Hoyt 1969; Hartmann et al. 1991; Brázdil et al. 2000)vision). (Walsh and Hoyt 1969; Hartmann et al. 1991; Brázdil et al. 2000)

Dissociations between perception and Dissociations between perception and consciousness after brain damageconsciousness after brain damage

(conscious perception and (conscious perception and unconscious /implicit, covert/ perceptionunconscious /implicit, covert/ perception))

Determination of hemispheric dominance

Interview about writing, eating with spoon, throwing a ball, kicking, step; tapping – domin. hand 50/min, nondomin. hand 45/min.

Left hemisphere is dominant in 95% right-handers and 60% left-handers!

Left hemisphere – dominant for speech and motor functions, reading, writing, counting, recognition of colors, verbal memory, important for linguistic thinking, ...

Right hemisphere – dominant for attentional functions, prosopognosia, prosodia (affective component of speech), nonverbal communication (ability to „read from face“), visuo-spatial perception, visual and topographical memory, recognition of music, …

Drug-induced mental disorders

Quite frequent, especially in elderly patients (mostly they are Quite frequent, especially in elderly patients (mostly they are caused by pharmacological polytherapy)caused by pharmacological polytherapy)

Depression, delirium, psychosis, agitation, aggressionDepression, delirium, psychosis, agitation, aggression

• Digitalis Digitalis • CorticosteroidsCorticosteroids• IndomethacineIndomethacine• PhenacetinePhenacetine• Phenylbutazone Phenylbutazone • CimetidineCimetidine• BenzodiazepinesBenzodiazepines• CaptoprilCaptopril• PropranololPropranolol• NiphedipinNiphedipin• PNCPNC• CephalosporinesCephalosporines• Oral contraceptivesOral contraceptives• VincristineVincristine

• CarbamazepineCarbamazepine• PhenytoinePhenytoine• PrimidonePrimidone• TopiramateTopiramate• ClobazamClobazam• PhenobarbitalPhenobarbital• LevodopaLevodopa• AmantadineAmantadine• AnticholinergicsAnticholinergics• ThyroxineThyroxine• InterferoneInterferone• … …....

; score > 24 normal; < 24 suggests dementia