Summary Capita Selecta in Medical Neuropsychology

Neuro-Oncology

CH 4: NEUROPSYCHOLOGICAL PROBLEMS IN NEURO-
ONCOLOGY

Introduction and History:

1. Neuropsychological studies in the field of oncology are related to
neuro-oncology:
- Brain tumors = arise from neurons and other brain tissue, cranial
nerves, leptomeninges, neuroendocrine glands, skull, and blood
vessels
- Treatment effects
2. 1800s = movement that integrated neurology and psychiatry
- More direct associations of psychological behaviors with brain
masses
- Psychiatric disturbances = thought to be the result of cerebral
tumor if primary and secondary effects of the tumor were global
- Localizationist movement in late 1800s
- Beginning of surgical resection of tumors with beneficial effects
on behavior

Frequency of CNS Tumors:

1. Only 20% diagnosed before age 20
2. Second most common malignancy and account for 20% of all
childhood cancers

Diagnosis of Brain Neoplasms:

1. Risks for developing a brain tumor:
- Usually, a brain tumor is found incidentally after a fall or accident
- Risks include:
o Serious head injuries decades before tumor is diagnosed (=
meningioma)
o Prior radiation exposure decades before diagnosis
o Immune suppression leading to symptoms

, o Genetic disorders
o Environmental changes and viruses
2. Tumor grading:
- Currently, four-level system decided by the American Joint
Commission on Cancer
- Previously, three-level system by WHO
- Grading system:
o Determines degree of malignancy of the tumor
o Classifies cells in terms of abnormal features (= informs
prognosis and treatment options)
o In general, brain tumor types are graded by:
 how abnormal the cancer cells and nuclei appears
 Direct observation of mitosis in genetic markers (=
indicates likelihood the tumor will grow or
disseminate)
- Tumor grading = used for the most common tumors (=
gliomas); a general classification is:
o Well differentiated and low grade
o Moderately differentiated and intermediate
o Poorly differentiated and high grade
o Undifferentiated and high grade
- Gliomas are classified as:
o Low grade/I = tumor cells remain well differentiated and
without other signs of abnormality in cell nucleus or tissue
structure
 Tumor cells grow slowly, rarely grow into surrounding
tissue, and may be gross totally resected
o Low grade/II = moderately differentiated but still benign
 Greater chance of de-differentiation and
transformation into more malignant tumor
 May have spread into surrounding tissue

, o Anaplastic/III = poorly differentiated; likely to spread into
secondary tissue; tumor is malignant
o IV = high grade, undifferentiated, highly malignant and
aggressive tumor; e.g., glioblastoma

Neuropsychological Mechanisms:

1. Tumor grade = related to severity of neuropsychological deficit
- Disrupt neural connectivity even if low-grade
2. Cognitive dysfunction = WM, attentional dysregulation, memory
encoding and retrieval, slowed info processing
3. Can also cause syndromes = aphasia, amnesia, dyspraxia,
executive dysfunction
4. Effects of tumors on cognitive function:
- Cause less functional damage than other more rapidly acquired
brain injuries
- Can appear as dementia or psychiatric syndromes
- Damage normal tissue by compression and infiltration
o Related biochemical causes:
 Herniation, edema, seizure genesis, and obstruction
of interventricular CSF (= with resulting
hydrocephalus)
- Surgical techniques:
o Attempt to limit the resection within the confines of the
tumor lesions
o Spare normal-appearing cortex and subcortical white
matter
- Tumors can infiltrate but usually cannot destroy tissue (= allow
for some neural function)
- Cause loss or displacement of white fiber tracts
5. Regional cognitive effects:
- Pattern of hemispheric specialization:
o Right cerebellar tumors result in greater linguistic and
sequential processing dysfunction

, o Left hemisphere tumors result in greater visuospatial
impairment
- Variability among patients due to tumor effects on cognition
being less severe
6. Regional effects in individuals:
- Slow growth of tumor = moderates the interference with
cognitive dysfunction
o May be followed by reduced cognitive recovery
- Stability or slow decline in specific cognitive functions over time
- Non-progressive tumors = rarely generalized decline in cognition
under treatment
- Stable tumor = relative stability of cognitive functions can be
very disturbed following resection
o Significant improvement for 1-2 years after resection (=
involves morphologic adjustment and neural plasticity)
o Subjective improvement in function
7. Individualized approach to neuropsych evaluation:
- Needed due to the diffuse nature of tumors
- It is a sensitive approach
- Effective in predicting tumor growth and can predict tumor
recurrence
8. Neurosurgery effects on cognitive function:
- Tumor effects on sensation, motor function, and cognition can be
exacerbated following surgical resection; new deficits may
emerge
- Surgical resection:
o Sudden onset disruptions in speech, motor function,
cognition and affect immediately after resection
o Improvement in cognition, personality, or mood (= related
to alleviation of mass effects)
- Cognitive function takes up to 2 years, at least, for recovery

Syndromal Neuropsychiatric Disturbances and Treatments: