Focal Neuropsychiatric Syndromes Flashcards
What are the divisions of the prefrontal cortex?
Dorsolateral
Medial
Ventromedial
What do lesions in the DLPFC lead to?
Classic dysexecutive syndrome
Difficulties in: Planning, organisation, idea generation, inflexibility, poor abstraction skills
Lack of concern for the past or for future consequences of actions
Forced utilisation behaviour may be seen (environmental dependency)
Psychometric testing is preserved
What are typical causes of DLPFC lesions?
Tumours
Cerebrovascular accidents
Frontal neurodegeneration
What is the frontal lobe paradox?
Psychometric testing is preserved but in the real world deficits in function will show
Tests are not ecologically valid
What are typical causes of Orbital PFC lesions?
Traumatic brain injury (road accidents, rotational force)
Frontal tumours
Multiple sclerosis
Frontal neurodegeneration
Anterior cerebral artery stroke
What are lesions in the orbital PFC associated with?
Behavioural problems: disinhibition, restlessness, impulsiveness, euphoria, aggression, inappropriate social behaviour impaired empathy, impaired theory of mind
L
Why might damage to orbital prefrontal cortex be unseen with functional imaging?
May be due to diffuse white matter damage
What is damage to the medial prefrontal cortex associated with?
Apathy and loss of initiative
Diminished motor activity
Indifference and reduced social interest
Hyperorality
Loss of insight
Bilateral missions lead to akinetic mutism
What are causes of damage to the medial prefrontal cortex?
Trauma
Hydrocephalus
Anterior cerebral artery occlusions
Tumours of the thalamus, 3rd ventricle, hypothalamus, and pituitary
What are some tests of frontal lobe function?
Luria’s motor sequencing - organisation of rapid sequence motor tasks
Desk tap test - cognitive flexibility
Proverb interpretation - abstract reasoning
Similarities/differences - abstract reasoning
Verbal fluency - testing phonemic or semantic verbal fluency
Cognitive estimates - testing ability to estimate
Stroop test (coloured words) - response inhibition
What is the function of the parietal lobe?
Perception of external space, proprioception, body image and agency
What is the effect of a lesion to the non dominant parietal lobe?
Disturbed body image
Impaired sense of position
Disowning of body parts (asomatognosia)
Dyscalculia
Neglect of left side of external space
What problems are lesions to the dominant parietal lobe associated with?
Anterior lesions - primary motor dysphasia
Posterior lesions - primary sensory dysphasia
Astereoagnosia - cannot name object based on feel (in hand) but can name when seen
Agraphesthesia - numbers or letters written on the skin may not be recognised as by touch
Parieto-occipital - visual agnosia
Cortical sensory loss
Impaired sensory localisation
Sensory and visual inattention
Contralateral hemiparesis
Contralateral homonymous lower quadrantopia
What are some clinical tests of parietal lobe function?
Drawing a clock face - neglect
Recognition of familiar object by touch - astereognosia
Reading - neglect
Writing - dysgraphia
Arithmetic - dyscalculia
Dressing - apraxia
Visual field examination - quadrantopia
What is the function of the ventromedial temporal lobe?
Emotional regulation (limbic system)
What is the function of the lateral temporal lobe?
Functionally complex neocortex:
Language
Hearing
Learning
Facial recognition
How might temporal lobe epilepsy present?
Deja vu
Jamais vu
Hallucinations: auditory, gustatory, visual
What would a lesion at the actuate fascicles cause?
Conduction aphasia caused by disconnection between Wernicke’s and Broca’s areas
Presents as: problems with repetition
What would lesions on the non-dominant temporal lobe cause?
Visuospatial problems
Prosopagnosia - recognition of faces (fusiform gyrus)
Receptive aprosody - comprehension of the emotional tone of speech
Phonagnosia - recognition of familiar voices
Where would a lesion be that leads to Wernicke’s aphasia?
Posterior superior temporal lobe
Where is the olfactory cortex located?
Uncus and parahippocampal gyrus
How might seizures affecting the middle and inferior temporal gyri present?
Complex hallucinations
Aberrant salience attributions to neutral perceptions
What would bilateral hippocampal lesions lead to?
Anterograde amnesia
What would bilateral amygdala lesions lead to?
Loss of fear
What syndrome might bilateral medial temporal lobe lesions lead to?
Kluver-Bucy
Placidity
Hypersexuality
Hyperorality
Hypermetamorphosis: compulsive exploration of environment
Inability to learn from aversive stimuli
What are some clinical tests for temporal lobe function?
Speech comprehension - receptive aphasia and aprosodia
Repetition - conduction aphasia
Writing/reading
Verbal memory
Non verbal memory - Rey Osterreith Complex Figure Test
What is the Rey Osterreith Complex Figure Test, and what does it test?
Test of non verbal memory
Patient copies complex figure and then is asked to reproduce the same figure 45 minutes later
What area would likely be damaged in contralateral homonymous upper quadrantopia?
Temporal lobe (deep)
contralateral homonymous lower quadrantopia?
Parietal lobe (deep)
How might damage to the corona radiata present?
Mild contralateral heniparesis
How common are posterior cortical artery strokes?
5% of all territory strokes - very common
What do lesions of the primary visual cortex lead to?
Visual blind spots (scotoma)
Partial blind spots (amblyopia)
What syndrome might bilateral occipital lesions present as?
Balint syndrome:
Inability to perceive the visual field as a whole (simultanagnosia)
Difficulty fixating the eyes (oculomotor apraxia)
Inability to move the hand to a specific object (optic ataxia)
What would extensive bilateral occipital cortex lesions lead to?
Cortical blindness
Why might someone with cortical blindness have “blind sight”?
Accessory visual pathway (superior colliculi and pulvinar bodies) are still working
What syndrome might bilateral occipitoparietal lesions lead to?
Charcot-Wilbrand
Loss of ability to create mental images (aphantasia)
To what clinicians might post cortical atrophy be presented first?
Ophthalmologists, opticians, neurologists
First symptoms are deterioration of visual function
Pathology predominantly affects the occipital lobe
Commonly caused by Alzheimer’s, dementia with Lewy bodies, corticobasal degeneration or Creutzfeldt-Jakob disease
How do visual areas in epilepsy differ from migraine?
Visual auras in epilepsy last seconds
Visual auras in migraine may precede the migraine by up to an hour
What are come clinical tests of occipital lobe function?
Visual field testing, including detection of object movement - anopias (hemianopia, quadrantopia)
Naming of familiar objects - visual agnosia
Reading ability - alexia
Interpretation and description of complex visual image -simultanagnosia
What are symptoms of thalamus dementia?
Amnesia
Confusion
Flat affect
Apathy
Personality changes
Hallucinations
What is the function of basal ganglia?
Release of inhibition of thoughts or behaviour
What are the components and function of the ventral striatum?
Caudate, putamen, nucleus accumbens
Emotional regulation and goal directed behaviour (addictions)
What are some features of cerebellar cognitive affective syndrome?
Executive dysfunction
Spatial cognition deficits
Language and effect problems
Personality changes
Disinhibition
What are the functions of the reticular formation of the brain stem?
Movement
Pain modulation
Wakefulness
Alertness
Arousal
What famous brain stem condition might ventral pons injury cause?
Locked in syndrome
What functions does the Raphe nuclei control (what functions does serotonin affect)?
Mood/affect
Sleep
Aggression
Appetite
Neuroendocrine functions
What is seen in pseudobalbar affect?
Pathological laughter or crying
