Bedside cognitive examination beyond the MMSE. Dr Richard Perry Dept of Neurosciences Imperial College

Transcription

1 Bedside cognitive examination beyond the MMSE Dr Richard Perry Dept of Neurosciences Imperial College

2 Overview Initial observations Cognitive rating scales Assessing cognitive domains Memory Language Visuospatial function Praxis Executive function and social behaviour

3 Initial observations Initial presentation self presentation, or brought How they walk Gait pattern, speed of movement Head turning sign First symptom Behaviour and personality changes interview informant

4 Cognitive rating scales MMSE ACE-R MoCA

5 Mini Mental State Examination Folstein et al 1975 Most widely used screening tool Takes 8 10 minutes Advantages Ease of administration Comparable across testing centres Suitable for longitudinal assessment Quick Disadvantages Poor on speed of processing and executive function Minimal assessment of memory Ceiling effect in MCI or FTD Limited inter and intra rater reliability

6 Addenbrooke s Cognitive Examination - Revised Includes subtests of MMSE but expanded to include more detailed tests to provide domain scores for memory, attention and orientation, fluency, language, and visuospatial function Scored / minutes to administer Cut-off score of 88 has sensitivity for dementia of 94% and specificity of 89% Lower cut-off score of 82% has higher specificity without major loss of sensitivity Combination of ACE-R plus 2 epsodic memory tests has good predictive power for conversion of amci to AD

7 ACE-R

8 Montreal Cognitive Assessment (MoCA) minutes Score / 30 Better sensitivity than MMSE for MCI Needs more clarity about cutoff scores? Mean score of normal population Cutoff at 26 gives high sensitivity but low specificity Suggested guide is <22 for MCI, AD < 17

9 Assessing different cognitive domains Memory Language Visuospatial function Praxis Executive function Social behaviour

10 cortical or subcortical Cortical Episodic memory Praxis Language Visuospatial Executive function Subcortical Processing speed Working memory Executive function

11 Orientation Orientation section of MMSE adequate for space and time Note disorientation to person suspicious for nonorganic disorder Catch is severely and suddenly aphasic patients

12 Memory - memory is not a unitary process Declarative memory Anterograde memory Working memory Explicit memory Retrograde memory Recall memory Semantic memory Implicit memory Procedural memory Episodic memory Long-term memory Short-term memory

13 Episodic Memory memory implicit explicit long term short term episodic semantic working

14 Episodic Memory 65 yr old man attended with his wife Two year history of gradual onset difficulty in memory for day-to-day things. Forgets to take messages Forgets where car parked Wife thinks that he is more repetitive Continues to work part time, manages hobbies and finances Bedside testing History MMSE poor ACE and MoCA better

15 CANTAB Mobile memory screening tool Episodic memory test PAL (Paired Associates Learning) Geriatric Depression Scale Activities of Daily Living Can be administered by nonmedical staff in 10 mins Sensitive to MCI Visual modality Different languages

16 Working memory Refers to the ability to temporarily maintain and manipulate information that one needs to keep on-line Traditionally divided into components that process phonologic information (e.g phone number in head) and components that process visual (mentally following a route) with central executive Overlap with attention Overlap with episodic memory poor working memory leads to faulty encoding Bedside task digit span, forwards and back

17 Semantic memory General store of conceptual and factual knowledge e.g. Colour of a banana, name of the Prime Minister, capital of France Not person or time specific culturally shared Spared in pure amnesic states such as Korsakoffs syndrome Inferolateral and anterior temporal lobe neocortex a key substrate for semantic memory

18 Semantic memory 65 yr old priest 2 yr history of difficulty remembering what things are called Day-to-day memory intact e.g conversations, appointments, recent family events Speech fluent but empty thing, place, doing etc Unable to remember the names of the twelve disciples or books of New Testament Diagnosis: Semantic Dementia a progressive neurodegenerative condition characterised by progressive loss of semantic memory

19 Testing semantic memory at the bedside Observation of speech fluent, empty, circumlocutions Naming objects, line drawings, providing semantic information about them Verbal fluency for categories e.g. animals, tools, fruit etc. Direct questions - e.g. what colour is grass, where do elephants live Reading irregular words surface dyslexia Knowledge of famous faces

20 Language Listen for: Aphasia vs Dysarthria Fluent or non-fluent Grammatically correct Paraphasic errors semantic, phonemic Impairment of prosody

21 Language Testing at bedside Comprehension single and multiple stage commands Repetition simple words such as toaster, then more complicated words such as catastrophe, then sentences e.g. the Chinese emperor s new fan Naming objects or drawings Reading note educational factors Writing and spelling

22 Progressive aphasia Non-fluent Adynamic Behaviour and personality Think: FTD (Pick s) PSP Non-fluent Logopaenic Agrammatic Acalculia Apraxia Gerstman s Think: AD CBD Fluent Empty, anomic Behaviour Think: SD

23 Dot counting Visuospatial function Scene description Copying line drawings Naming objects Naming faces Degraded letters

24 Visuospatial function 62 yr old man Difficulty in proof reading Difficulty in telling time from clock Digital clock OK Couldn t see things right in front of him 18 F FDG PET 11C PIB PET

25 Praxis and apraxia Inability to perform skilled motor movements in the absence of deficit of power or sensation Although usually associated with lesions in the left parietal lobe, apraxia may also be seen after lesions to the right parietal lobe, frontal lobes and subcortical structures in the basal ganglia. Terminology of subtypes of apraxia confusing and not often relevant in clinical practice

26 Praxis and apraxia Praxis is a predominantly cortical function Should be normal in psychiatric disease Look for associated myoclonus Look for extrapyramidal features

27 Executive function not synonymous with frontal lobe function at the bedside: verbal fluency - letters and categories backward digit span proverbs cognitive estimates go-no-go tasks alternating hand-movements Luria 3-step

28 Summary and conclusions Possible to get quantative assessment at bedside of many cognitive and behavioural functions with minimum props Keep in mind which brain areas are affected Keep question of cortical or subcortical in mind Keep question of organic / functional or neurological / psychiatric in mind

29 Acknowledgements Dr Angus Kennedy, CXH, London Dr Paul Bentley, CXH, London Dr Peter Garrard and Dementia Research Group, NHNN, London Dr Bruce Miller, University of California, San Francisco Dr Bob Levenson, University of California, Berkeley