Neuropsychological Diseases

1. Neuropsychological Diseases Tumors, toxins, and CVAs Seizure Disorders (Epilepsy) Parkinson’s Disease Huntington’s Disease Multiple Sclerosis Alzheimer’s Disease Creutzfeld-Jakob Disease

2. Seizure Disorders (Epilepsy) • Seizures may be from trauma, illness, or drugs. These are usually reversible. • Chronic seizure patterns generated by brain dysfunction are called epilepsy.

3. Symptoms of epilepsy • Convulsions: • Tremors or clonus • Rigidity or tonus • Loss of balance and consciousness • High-amplitude EEG spikes • Epileptic auras • Provide clues to the location of the focus • Provide warning of an impending seizure

4. Partial seizures • Affect only part of the brain at a time • May be simple or complex • Simple partial (Jacksonian) seizures: Spreading sensory or motor or combined effects • Complex partial seizures or temporal lobe epilepsy begin with an aura and lead to a psychomotor attack: automatisms with consciousness but no recollection. Most common variety: 50% of all cases.

5. Generalized seizures • Involve the entire brain, either by gradual building or simultaneously, perhaps from a focus in the thalamus. • Grand mal seizures • Tonic-clonic convulsion • Loss of consciousness and balance • Hypoxia from excessive excitatory amino acids

6. Generalized seizures • Petit mal or absence seizures • 3-per-second spike-and-wave EEG pattern 1 second Common in children, often end at puberty: Labelled daydreamers and space cadets.

7. Parkinson’s disease • Multiple causes: genetic error, infection, stroke, trauma, neurotoxins, idiopathic • Damage to substantia nigra in midbrain • Normally dampens the responsiveness of the caudate nucleus of the striatum of basal ganglia • Symptoms include resting tremor, difficulty starting or stopping movement, flattened facial expression or emotion. Intellect is intact.

8. Parkinson’s disease • Treatment: • L-DOPA (levorotatory dihydroxyphenylalanine) • Deprenyl (selegeline, Eldepryl) • Dose-dependent MAO-B Inhibitor • May inhibit DA uptake at the synapse • Metabolites include amphetamine and methamphetamine, which inhibit uptake and increase release of DA, NE, and 5-HT • Discovered through the MPTP episode.

9. Huntington’s disease • Caused by a single dominant gene • Progresses from fidgety motor behavior to chorea to dementia to death • Symptoms start after age 40, last 15 years • No cure, but a test is available.

10. Multiple sclerosis • Scarred hardening (sclerosis) of myelin • Hypothesized cause: A slow-acting infection of childhood leading to autoimmune reaction against myelin, in genetically susceptible people • Disrupts sensation, especially vision and touch • Produces weakness, tremor, ataxia, and loss of bladder control

11. Alzheimer’s disease • A progressive dementia associated with advancing age, it affects about 10% of people over age 85. • Behavioral symptoms are similar in several of the dementias: Alzheimer’s diagnoses are confirmed post-mortem by the presence of neurofibrillary tangles and amyloid plaques • There is significant loss of neurons

12. Alzheimer’s disease • Damage is greatest in the entorhinal cortex, amygdala, and hippocampus, all in the medial temporal lobe and all involved in memory; and in the temporal, parietal, and prefrontal cortex, all involved in complex thought. • Genetic component on chromosome 21, 14, or 19 produces 50% risk in immediate family members who live to be 80 - 100.

13. Transmissible Spongiform Encephalopathies: Creutzfeld-Jakob Disease and “Mad Cow Disease” • A viral infection, CJD comes in two forms: • Variant CJD has been linked with mad cow disease which has claimed a number of lives in the United Kingdom. • The other strain, typical CJD, has a 30-year incubation period, so normally occurs in older people.