Week 4: Remembering and forgetting, examples of critical sense in clinical practice. Flashcards
2x2 issue with double dissociations - what does this assume?
Assumes the system has only 2 working componants
Other types of neglect that have been reported (other than visual /// perceptual neglect)? There are 4 types
- near vs far space neglect
- personal vs near space neglect
- implicit vs explicit neglect (not aware of deficit vs aware of defecit)
- object-based (half of object attended to) vs space based neglect
(Marshall and Halligan, 1988) - demonstration of implicit vs explicit neglect
- subject has implicit visuo-spatial neglect
- when shown 2 pictures of a house either side of each other, one of houses on fire
- asked if 2 houses are different - they reply no
- but when asked which of the houses they would rather live in, they pick the house that is not on fire (implied awareness that house is on fire)
Features of PERSONAL neglect
- More common with lesion to RHS
- hemispheric asymmetry with regards to directing proprioception
- LHS is more used for EGOCENTRIC ATTENTION (eg evaluating the strength of a tactile stimulus
- neglect associated with many cortical and subcortical lesion sites
- double dissociation with EXTRAPERSONAL neglect seen –> the two are underpinned by different anatomical or functional modules
What does hemispheric asymmetry with regards to directing proprioception mean
RHS of the brain has a more significant role than the left in directing and encoding spatial information surrounding objects relative to other objects (in the case of personal neglect, the limb)
Why may personal neglect go beyond attention and include defecits of body representation?
Somatosensation is a highly integrated cognitive and proprioceptive system
What sub cortical/subcortical structures have personal neglect been associated with?
Thalamus
Internal capsule
Basal ganglia
What is Anosognosia?
Unawareness of having a motor or cognitive impairment
Causes, common symptoms and problems with diagnosis of Anosognosia?
Common anasognosia is visuospatial neglect
Causes: lesions or damage to the R hemisphere, aspects of personality (Weinstein & Kahn, 1955), specific cognitive damage
Diagnostic issue: L brain anosognosia = underdiagnosed!
‘Assessing Anosognosia: a critical review’ (Cocchini, Beschin, Della Sala, 2010) - 3 types of assessing Anosongnosia?
Strucutred interviews –> assess patient awareness of their own defecits
Self rated questionnaires –> ask patients about their ability to carry out tasks and level of self awareness
VATAm (Della Sala, 2009) –> a visual analogue test which demonstrates certain tasks with pictures
‘Assessing Anosognosia: a critical review’ (Cocchini, Beschin, Della Sala, 2010) - problems with assessing Anosognosia?
2 of The methods rely too much on verbal competency People with language or reading defecits may not be diagnosed Unreliable methods (hence VATAm was developed)
(Cocchini et al., 2009) inflated RHS diagnosis of Anosognosia –> outline study
Used structured interview on 1 group of patients and VATAm on 1 group of patients, both groups with lesions to the LHS of the brain.
Using the VATAm, 40% of patients with LH lesions diagnosed with Anosognosia. only 10% with structured interview
(Cocchini et al., 2009) inflated RHS diagnosis of Anosognosia –> conclusions and implications of study
VATAm = 60% more reliable method of diagnosis
Lower diagnosis of LHS could be due to multi-faceted nature of Anosognosia –> RHS and LHS play different roles, but LHS does process awareness of defecits too
(Beschin et al., 2012) Neglect and Anosognosia –> dissociation of treatment effects – OUTLINE STUDY
5 patients with both neglect and Anosognosia (both have been demonstrated separately in the past).
Test patients with TECHNIQUES found to alleviate Anosognosia
What 3 techniques have been found to alleviate Anosognosia?
Optokinetic stimulation
Prismatic shift of the visual field
Transcutaneous nerve stimulation
(Beschin et al., 2012) Neglect and Anosognosia –> dissociation of treatment effects – TEST FINDINGS?
2 responded to the treatments for neglect but NOT for Anosognosia
1 showed the reverse
DISSOCIATION OF TREATMENT EFFECTS –> supports the notion of double diss between neglect and anosognosia
What things are assumed by a diagnosis? What will, therefore, a skilled neurologist attempt to do ?
- a disease has been identified
- the cause of the disease is known
A skilled neurologist will attempt to investigate the CAUSE of an impairment, and these causes will be multi-various
How is a neuropsychological assessment structured? (Cubelli, Della Sala, 2015)
1) interview to explore symptoms
2) screening to use tests to identify problem areas
3) neuropsychological examination to allow clinical labelling
4) experimental tests , ad hoc, which are derived from literature from investigating known cognitive models
‘A single case of deep dyslexia’ - (Cubelli, Pedrezzi, Della Sala, 2015) - outline case BR
- left middle cerebral artery stroke
- Broca’s aphasia
- deep dyslexia seen (difficulty reading words, unable to read nonwords)
- heterogeneous defecits observed
A single case of deep dyslexia’ - (Cubelli, Pedrezzi, Della Sala, 2015) - what did assessment of case BR demonstrate
Demonstrated that assessment and clinical case formulation should not be limited to labelling behavioural disorders
Thorough analysis to give a performance profile would be better than ‘pass/fail test’
During case assessment why is thorough analysis to give a performance profile better than ‘pass/fail test’?
Passing or failing a test doesn’t necessarily give an indication or proper analyis of cognitive or cortical functioning
Neuropsychological tests can fail for many reasons (unreliable, patient has poor reading or verbal skills, etc etc) –> assessment should therefore follow the structure of a scientific investigation
This willl give a MORE PRECISE CLINICAL DIAGNOSIS based on KNOWN COGNITIVE MODELS
