Page 770 - TNFlipTest

N28 Neurology
Mild Traumatic Brain Injury Toronto Notes 2019 • inabilitytoperformskilledvoluntarymotorsequencesthatcannotbeaccountedforbyweakness,
Apraxia
Definition
ataxia, sensory loss, impaired comprehension, or inattention
Clinicopathological Correlations
Table 14. Apraxia
Ideomotor
Ideational Constructional* Dressing*
Description
Inability to perform skilled learned motor sequences
Inability to sequence actions Inability to draw or construct Inability to dress
Tests
Blowing out a match, combing one’s hair
Preparing and mailing an envelope Copying a figure
Dressing
Hemispheres
Left
Right and left Right and left Right
*Refers specifically to the inability to carry out the learned movements involved in construction, drawing, or dressing; not merely the inability to construct, draw, or dress. Many skills aside from praxis are needed to carry out these tasks.
Agnosia
Definition
• recognitionofthesignificanceofsensorystimuliinthepresenceofintactsensationandnaming
Clinicopathological Correlations
Parietal Lobe Lesions
• Lesions of the dominant parietal lobe are characterized by Gerstmann’s syndrome: acalculia, agraphia, finger agnosia, and left-right disorientation
• Lesions of the non-dominant parietal lobe are characterized by neglect, anosognosia, and asomatognosia
• Cortical sensory loss (graphesthesia, astereognosis, impaired 2 point discrimination and extinction) can be seen with left or right parietal lesions
• Extent of retrograde amnesia correlates with severity of injury
• Regained from most distant to recent memories
Table 15. Agnosias
Apperceptive Visual Agnosia Associative Visual Agnosia
Prosopagnosia
Colour Agnosia Impaired Stereognosis
Finger Agnosia
Description
Inability to name or demonstrate the use of an object presented visually 2o to distorted visual perception Recognition by touch remains intact
Inability to name an object presented visually 2o to disconnect between visual cortex and language areas Visual perception is intact as demonstrated by visual matching
Inability to recognize familiar faces in the presence of intact visual perception and intact auditory recognition
Inability to perceive colour
Inability to identify objects by touch
Inability to recognize, name, and point to individual fingers
Lesion
Bilateral temporo-occipital cortex
Bilateral inferior temporo-occipital junction
Bilateral temporo-occipital areas or right inferior temporo-occipital region
Bilateral inferior temporo-occipital lesions
Anterior parietal lobe in the hemisphere opposite the affected hand
Dominant hemisphere parietal-occipital lesions
Mild Traumatic Brain Injury
Definition
• mildTBI=concussion
• traumainducedtransientalterationinmentalstatusthatmayinvolvelossofconsciousness
• hallmarks of concussion: confusion and amnesia, which may occur within minutes
• loss of consciousness (if present) less than 30 min, initial GCS between 13-15, and post-traumatic
amnesia less than 24 h
Epidemiology
• 75%ofTBIsareestimatedtobemild;theremainderaremoderateorsevere(seeNeurosurgery,NS32 and Emergency Medicine, ER8)
• highestratesinchildren0-4yr,adolescents15-19yr,andelderly>65yr
Clinical Features
• impairmentsfollowingmildTBI
■ somatic: headache, sleep disturbance, nausea, vomiting, and blurred vision
■ cognitive dysfunction: attentional impairment, reduced processing speed, drowsiness, amnesia ■ emotion and behaviour: impulsivity, irritability, depression
• severeconcussion:mayprecipitateseizure,bradycardia,hypotension,sluggishpupils • associatedconditions:braincontusion,diffuseaxonalinjury,C-spineinjury