Secondary (Recent) Memory

Secondary memory

Declarative Procedural

Episodic Semantic Skills PrimingClassical

Conditioning

Declarative Memory

Knowing that Explicit knowledge Tulving: Two subdivisions

i) Semantic

ii) Episodic

Episodic Memory

Memories that depend on temporal, spatial or contextual cues in order the retrieve the information (= explicit memory)

Consists of additional knowledge of personal experience

Involves remembering specific events and episodes in the context in which they occur

***Typically disrupted in amnestic conditions

Measures of Episodic Memory

Numerous

Examples:WMS-IV/WMS-III: Paired

Associates, Logical Memory, Visual Reproduction, Designs

Rey Complex FigureRAVLT/CVLT/SRT

Selective Reminding Test

A taxonomy of memory disorders

AMNESIA

Neurological Psychogenic

Selective Amnesia

PsychoticConditions

Permanent Transient

Transient Global Amnesia

Post-Traumatic Amnesia

Post ECT or Convulsion

Progressive

Stable

MaterialSpecific

Global

Frontal Amnesia

Amnesic Syndrome

Cerebral hemispheres

Material Specific Memory Disorder

Reflection of lesion laterality – Pathology of the dominant V’s nondominant hemipshere

1. Temporal Lobe Epilepsy (TLE)Milner (1958, 1962): Patients undergoing unilateral temporal lobe resection for relief of intractable complex partial seizures

Temporal lobectomy: Anterior portion (5cm) of temporal lobe removed including the anterior portion of the hippocampus

Memory Disorder: Material specific not modality specific

Left TL resection: Verbal Memory Deficit

(logical memory, word lists)

Right TL resection: Nonverbal Memory Deficit

(maze learning, design recall, recall of faces)

Hippocampus thought to be the important structure

TLE – Case Example

Case: KE Age: 19 years Sex: Female History: 6 month history of

complex partial seizures Eduction: HSC graduate,

Commenced first year of a degree in PE teaching – deferred due to memory problems

Index Index Score

Verbal Comprehension 101Perceptual Reasoning 108

Working Memory 109Processing Speed 95

Full Scale 101General Ability 1`05

KA: Wechsler Memory Scale-IV (WMS-IV)

Index Score

Auditory Memory 87

Visual Memory105

Visual Working Memory 109

Immediate Memory 95

Delayed Memory 71

KA: Further Memory Testing

Selective Reminding TestCLTR = 50 (Mean = 115, SD = 15.5)

Recognition Memory TestScale Score

Words 5Faces 11

15-Item Visual Memory TestRaw score = 15/15

15-Item Visual Memory Test

A B C

I II III

a b c

1 2 3

KA: Assessment of adaptive abilities

Controlled Oral Word Association Test (COWAT)Words = 39 (Mean = 41.5, SD = 6.7)

Wisconsin Card Sorting TestCategories = 6Perseverative Responses = 11

Rey Complex Figure TestCopy = 34, Recall = 22

Booklet Category TestErrors = 23

KA: Rey Figure Copy

KA: Rey Figure Recall

Material Specific Disorders of Memory (con’t)

2. Cerebrovascular DisordersDisruption of brain function secondary to

vascular pathology (includes haemorrhage (rupture), narrowing (stenosis) and occlusion due to presence of an obstructing clot (thrombus or embolus)

Branches of the posterior cerebral artery supply the inferior and medial surfaces of the temporal lobes and posterior sections of the hippocampus. Thus, infarction (tissue death) may result from occlusion and produce a material specific memory disorder

Unilateral thalamic infarction (secondary to PCA disturbance) may also produce a material specific disorder of memory.

Specific Disorders of Memory

Topographical disorientationDamage to the right tempero-parietal areas (MCA)

Unable to find way around.

Tactile MemoryImpairment reported in patients with unilateral temporal lobe lesion resulting from CVA with loss demonstrated in hand contralateral to the lesion.

BS: Lateralised (R.Hem) Dysfunction

45 yo female 9 years education DSS (clerical) for 17 years 3-4 months preceding ABI worked as a taxi

driver

1/1/02 assaulted during the course of her work

PTA: several days duration (no recollection of visitors while in hospital, son receiving HSC results)

CT (2006): Local area of enlargement of the temporal horn of the right lateral ventricle, enlargement of the right Sylvian fissure. Appearances consistent with an area of local atrophy.

Psych Tx for PTSD

Psychiatrist noted that she intermittently complained of memory problems and geographical disorientation

Case BD

Assessment

February 2007

Attended unaccompanied

Fully cooperative

c/o - memory problems (eg. Forgets where she is meant to be driving to, gets lost even when driving to familiar places, misplaces her personal belongings) - irritability

WAIS-IV

Verbal IQ = 116 PIQ = 110 Working Memory = 117 Processing Speed = 104 Full Scale IQ = 111 General Ability = 113

WMS-IV

INDEX ACTUAL PREDICTED

Auditory Mem 103 106

Visual Mem 75 106

Visual Working Mem

108 107

Immediate Mem _ 107

Delayed Mem _ 106

Base Rates (General Ability)

AM - >25%

VM - <1%

BD: Additional Memory Tests

Selective Reminding Test

Consistent Long-Term Retrieval – Average

Rey Complex Figure Test

Copy = 25

Recall = 4.5 (<1st percentile)

BD: Adaptive Abilities and Emotional Status

Trail Making TestPart A = 26 seconds, 0 errorsPart B = 50 seconds, 0 errors

Controlled Oral Words Association Test (COWAT)Words = 45, Errors = 3

Wisconsin Card Sorting TestCategories = 6, Errors = 12Perseverative Responses = 6 (Above Average)

Booklet Category TestErrors = 107 (Impaired)

Depression, Anxiety, Stress ScalesDepression = 40 (Ex.S.), Anxiety = 36 (Ex.S.), Stress = 32 (Ex.S.)

BD: Opinion

The results of the assessment revealed clear evidence of cognitive impairment. Although generally able to achieve at an average to high average level on measures of verbal ability, her nonverbal skills proved markedly disordered. Specifically, she demonstrated difficulty in acquiring, retaining and processing visuospatial material. Although she is clearly suffering significant levels of emotional distress, reference to these factors alone would not appear to be sufficient to account for all of the deficits seen on testing.

Neither depression nor anxiety would be expected to produce a material-specific disorder of memory and adaptive ability. A disparity between performance on measures of verbal and nonverbal ability, when of the magnitude that was evident in the present case, is strongly suggestive of lateralised cerebral pathology. The profile of performances returned on testing would suggest that there has been damage to the frontal and temporal lobes of the nondominant (right) hemisphere. The CT report provides independent evidence of focal damage to these areas.

BD: Opinion (con’t)

Given the results of the assessment it is not surprising to learn that BD complains of a tendency to get lost while driving and occasion geographic disorientation. The ability to remember routes and to understand spatial relations is known to be mediated by the right hemisphere. Recalling the temporal detail of various events is thought to represent one of the functions that is subserved by the frontal lobes. As stated above, the results would suggest that these areas have been damaged.

BD: Opinion (con’t)

On a day to day level BD’s deficits are most likely to manifest as a difficulty in recalling visual information (scenes, routes, faces etc), a difficulty in planning her approach to nonverbal tasks (eg. when assembling an item or dealing with procedures that involve a number of steps) and an inability to reason and problem-solve in the nonverbal modality. She may experience difficulty in learning the requirements of any new position, particularly if the work involves nonverbal displays or tasks. She should be encouraged to verbalise information and to make written note of new procedures. Her ability to operate a computer may be

compromised in that she is likely to find it difficult to remember the meaning of various symbols and the full range of responses that a particular visual cue is designed to elicit. Even when her mistakes are drawn to her attention she is likely to have difficulty in generating some alternative method of response. Modelling of the correct procedure would be of use. Flow-charts or other nonverbal displays are unlikely to be of assistance.

Frontal Amnesia

A. Organisational Deficits

Simple registration and recall not affected by frontal lesions

Memory problems may be secondary to an inability to organise material for the purpose of committing it to memory

i.e. failure to impose a meaningful structure on the information, to generate appropriate learning strategies

Frequent concomitant of traumatic brain injury

Manifest on tests such as Rey Complex Figure, Rey Auditory Verbal Learning

Frontal Amnesia

B. Retrieval Problems

Retrieval involves strategic problem-solving. Often disturbed following frontal lesions

Patient with a retrieval deficit will demonstrate a disturbance of free recall

Recognition memory should, however, be intacteg. RAVLT: poor score on recall of list A (trials 1-

6) recognition 15/15

One advantage of WMS-III relative to WMS-R

Frontal Amnesia

C. Temporal Discrimination

Increasing attention being devoted to this aspect of memory

Patients with frontal lesions are markedly impaired in making temporal discriminations. Great difficulty in judging recency and temporal order and in reconstructing sequences.

Note, deficits of temporal ordering may be seen in the absence of fontal lobe pathology

Two processes involved:a) Encoding of information needed for temporal

memoryb) Effective processing of retrieved information

regarding temporal order

In patients with lesions of the frontal lobes deficit lies in b) ie. Is one of faulty processing (c.f. WKS patients where the deficit lies in a)).

General Amnesic Syndrome

Definition

A permanent, stable and global disorder of memory due to organic brain dysfunction which occurs in the absence of any other extensive perceptual or cognitive disturbance.

NB. PermanencyStabilityPervasivenessSpecificity

Clinical Features of the Amnesic Syndrome

1. Profound difficulty or total inability to acquire new material (anterograde amnesia)

2. Preservation of immediate memory as measured by tasks such as digit span

3. Preservation of semantic memory

4. Preservation of procedural learning

5. Some retrograde amnesia (variable across patients)

Neuopathology

Brain structures implicated:1. Bilateral damage to the mesial temporal

lobes of both the right and left hemispheres

Within these areas the hippocampus has been seen to represent the crucial structure

2. Structures within the diencephalon and specifically:Nuclei within the thalamusMamillary bodiesMamillo-thalamic tractFornix

All above structures represent part of the limbic system

Aetiology

GAS typically seen in association with

1. Wernicke-Korsakoff Syndrome2. Herpes Simplex Encephalitis3. Hypoxia4. Anterior Communicating Artery

Aneurysm5. Thalamic Infarction6. Temporal Lobe Resection

Other causes:CVATumour

Wernicke-Korsakoff Syndrome

Typically the result of chronic alcoholism

Principle cause: Thiamine deficiency

Results in damage to the subcortical structures and in particular the diencephalon

Minimal requirement: Lesion of the mamillary bodies and dorsomedial nucleus of the thalamus

Typically additional lesions in the frontal lobes (atrophy) due to alcohol neurotoxicity and often the medial temporal structures including the hippocampus

Treatment. Thiamine. Amnesia often persists

WKS: Characteristics

1. Normal memory span2. Severe anterograde amnesia3. Normal rate of forgetting4. Extensive, temporally graded

retrograde amnesia5. Confabulation present6. Cued recall better than

spontaneous recall7. Recognition relatively intact8. Poor at recency judgements9. Frontal lobe dysfunction

typically present