Behavior, Cortical Function, and Dementia Flashcards
What is memory?
The ability to learn and then recall information after different periods of time
What is “immediate” memory?
The pre-requisite state of attentiveness required for learning something
How can you determine if “immediate” memory is intact? If it appears to not be intact, what are possible causes?
Patient should be alert and awake enough to immediately repeat or recite a sequence of 5 numbers spoken out loud
Excessive sleepiness
Sedation from medications
Systemic illness diffusely inhibiting cortical function
Lesions affecting the RAS more directly
Impaired ___ precludes any reliable testing of recent or remote memory as well as other cortical functions.
Attention
What is recent or “short-term” memory?
Ability to recall information after several minutes of retention
How is short-term memory tested?
Patient is given 3 items to repeat aloud and instructed to recall them 5 minutes later on command
What is remote or “long-term” memory?
Ability to recall past events hours, weeks, or even years afterward
How is long-term memory tested?
Ask a prior address or anniversary date for which the correct answer is known
Memory function depends on what pathways?
Bilateral pathways involving the temporal lobe and thalamus, specifically hippocampus -> fornix -> mammillary body -> anterior thalamic nucleus
What causes amnesia in Wernicke-Korsafoff syndrome?
Bilateral thalamic and mammillary body lesions; caused by thiamine deficiency in malnourished alcoholics
What are 2 other causes of bilateral hippocampal lesions causing amnesia?
Anoxia
Herpes simplex encephalitis
What is apraxia?
The inability to conceptualize and perform a skilled, learned, motor act on command
What kind of lesions may cause gait apraxia (inability to walk on command)?
Prefrontal lobe lesion
What kind of lesions may cause a constructional (cannot draw a house or copy a drawing) or dressing (cannot put on and button a shirt) apraxia?
Posterior cortical lesions, especially involving the parietal lobe
What is agnosia?
Impaired recognition of perceived stimuli caused by lesions of sensory association cortex
Lesions of particular lobes of the cerebral hemispheres often involve what 4 general etiologies?
Head trauma
Stroke
Tumor
Dementia
Presentation of patients with pre-frontal or frontal lobe syndrome?
Listless, apathetic, unconcerned
Poor hygiene, incontinence
Poor judgment and disinhibition -> outbursts, rude humor, inappropriate sexual behavior
Executive functions are impaired (poor planning and performance of multistep or novel tasks, lack of creative thinking, limited attention, motor perseveration)
Gait apraxia
Paratonia
Frontal lobe release signs
What is paratonia?
Increased limb tone or resistance is felt as the examiner moves the patient’s limb more rapidly
What are frontal lobe release signs?
Previously normal findings during infancy when myelination of descending inhibitory pathways was incomplete -> sucking reflex, rooting reflex, palmar and plantar grasps
Presentation of syndromes of the temporal lobes?
Amnesia (bilateral hippocampal lesions)
Cortical deafness (bilateral auditory cortex lesions)
Kluver-Bucy syndrome (limbic system)
Unilateral lesion of superior-posterior dominant temporal lobe -> Wernicke’s aphasia
Presentation of syndromes of the parietal lobes?
Asterognosis
Agraphesthesia
Extinction on double simultaneous stimulation
Impaired spatial relationships between the body and its surrounds if lesion of the non-dominant parietal lobe -> anosognosia (unaware of hemiparesis), hemispatial neglect
What is Gerstmann’s syndrome?
Agraphia
Right-left disorientation
Dyscalculia
Finger agnosia
What causes Gerstmann’s syndrome?
Lesion of the supramarginal or angular gyrus of the dominant parietal lobe
Presentation of occipital lobe syndromes?
If enough bilateral visual cortex is involved -> cortical blindness
