Cognitive neurology

The study of how neurological disease and injury affect cognition, using clinical patterns and experiments to constrain explanations of normal cognitive function. A brain lesion can disrupt connected regions and several computations, so a syndrome is evidence to explain rather than a complete processing model.

Reduced goal-directed activity or motivation relative to a person’s previous functioning. Initiation, valuation, effort and emotional experience require separate assessment; inactivity is not automatically anhedonia or motor incapacity.

A marked reduction of spontaneous initiative or willful activity. Preserved behavior after prompting can help distinguish impaired self-initiation from inability to execute the same action.

A severe reduction of spontaneous mental and behavioral activity that improves with external stimulation or instruction. Clinical descriptions after bilateral basal ganglia injury motivated experiments separating self-activation, incentive translation and motor capacity.^[ref]

A progressive syndrome with deterioration of conceptual knowledge, often accompanied by fluent speech, anomia and poor word comprehension. Nonverbal semantic tests are important for distinguishing broad conceptual impairment from an isolated language-output problem.^[ref]

Impaired recognition of visually presented objects not adequately explained by elementary visual loss or a general inability to respond. Testing other sensory routes and nonverbal knowledge helps locate the difficulty.

A visual-recognition disorder attributed to difficulty accessing meaning from a relatively adequate visual representation. Copying can provide evidence about perception, but line-by-line copying alone does not demonstrate normal integration.^[ref]

A visual-recognition disorder in which constructing or integrating an adequate perceptual representation is impaired. The specific perceptual demands must be established rather than inferred from recognition failure alone.

Impaired awareness of a neurological deficit. Its assessment must distinguish the underlying deficit, a person’s report and evidence that they understand the relevant questions.

Difficulty performing learned actions not adequately explained by elementary weakness, sensory loss or failure to understand the instruction. Different clinically named forms need not share one processing mechanism.

Difficulty organizing dressing actions that can involve relationships between clothing, the body and space. Motor limitations, understanding and neglect require separate assessment.

A traditional clinical term for impaired copying, drawing or assembly of spatially organized material. Failures can involve spatial representations, neglect and planning rather than one general motor-program deficit.

Inaccurate visually guided reaching not adequately explained by elementary visual loss or weakness. Comparing gaze, hand and target conditions helps identify the affected visuomotor demands.^[ref]

A disproportionate failure to attend or respond to events on one side of space, often contralesional to brain injury. It may affect external space, the body or internally generated scenes and can occur without an equivalent primary visual-field loss.^[ref]