Pathways Ventral cochlea – encodes intensity information Dorsal cochlea – encodes information and analyzes quality of sounds (e.g., differentiates phonemes) Organ of Corti –the auditory transductor, which consists of cells which bend in response to sound waves Info from one ear may travel via a number of different routes to reach the auditory cortex of … Read more
SALIENT CHARACTERISTICS OF ATTENTION Sequential process involving many brain systems Limited capacity- engagement of system in one task can interfere with second task Varies between and within individuals under different conditions (depression, fatigue, injury can all impact attention) NEUROANATOMICAL SUBSTRATES Inferior Parietal Cortex– spatial selective attention; hemineglect Frontal Cortex– response selection; control; sustained attention; switching; … Read more
DEFINITION Apraxia – derived from Greek word, praxis, meaning to do or action An acquired disorder of skilled purposeful movement purposeful important b/c may do automatically (e.g., can spontaneously brush crumbs off lap but can’t do so on command or intentionally) Syndrome of higher motor dysfx distinct from paresis in same way aphasia distinct from … Read more
Aphasia Syndromes Summary Speech Auditory Comprehension Repeating Naming Broca’s . — Normal . – . – Wernicke’s Fluent . — . — . – Conduction Fluent Normal . — . – Global . — . — . — . – Anomic . – Normal Normal . — KEY: – = minor impairment — = … Read more
The brain accounts for 2% of a person’s total body weight, but it consumes 20%-25% of the total oxygen inspired While other organs can withstand deprivations of oxygen for extended periods of time, the brain can be effected by even subtle deprivations If anoxia continues for more than a few minutes, an anoxic/ischemic encephalopathy will … Read more
Tardive Dyskinesia Some suggest that over ½ TD pts unaware of their movement disorder (have been larger prevalence rates: 88%) Some suggests that unawareness of TD might be due to primary illness (SZ>BP for unaware). Some suggest they’re denying the disorder /hiding it (thumb in clenched fist; tongue against top/ bottom teeth) Expect OF>LT (unaware) … Read more
DEFINITION Alexia is an acquired deficit in the ability to interpret written language; does not refer to those impairments (congenital or acquired early in life) which prevent the normal acquisition of reading skills (which are considered developmental dyslexia or simply dyslexia) HISTORY Recognized for centuries, but became a significant problem only in 20th century, when … Read more
DEFINITION Agraphia – an acquired deficit in the ability to produce written language Commonly used interchangeably with dysgraphia HISTORY Term first employed by Ogle (1867) to describe pt who could speak but not write Since then, numerous classification systems have been proposed, but none universally accepted Two general nosologies: 1 longstanding tradition in context of … Read more
DEFINITION Agnosia: From Greek word, gnosis, or knowledge, so means absence of knowledge Fundamentally defined as a disorder of recognition; inability to recognize the meaning of info conveyed w/in a given sensory system from external environment to the brain Crucial feature is that it exists only in single sensory modality NOT attributable to elementary sensory defects, mental … Read more
General Considerations See also the broader discussion of Aging and Cognition Many aspects of memory deteriorate w/ age Decline affects recent memory more than immediate or remote Ability to encode, store, and recall info is typically reduced in older adults; that is, memory processes become less effective, although the content of memory (knowledge) can continue to … Read more