Chapter 2: Mental Status
Author's Commentary
The mental status defines the state of the brain circuitry that is essential for consciousness, executive function, mood, and affect.
All normal people are oriented to time, place, and person. Time may be the most subtle component of this orientation, as a great number of people are oriented to time within 15 minutes.
Memory has been divided into many subcategories:
- Explicit refers to memories that can be consciously recalled.
- Implicit memory is registered without conscious intent.
- Working memory is that body of knowledge that can easily be recalled and utilized for activities of daily living.
Neurologists frequently divide memory into inscription, consolidation, and recall:
- Inscription occurs during the first 30 seconds (possible reverberation of circuits of the hippocampus).
- Consolidation starts at 30 seconds and proceeds up to 3 minutes (replayed during deep sleep).
- Long term memory depends on protein synthesis and may be stored throughout the brain
Specific nuclei and areas of the brain affect the different components of memory. Judgment is a component of executive function but also probes some aspects of psychiatry.
Affect is a patient’s “feeling tone." Every intracranial process affects this aspect of the mental status. Each cortical and brain stem circuitry effects affect differentially. Intellectual function is the sum total of information amassed by the patient. The patient’s basic knowledge and ability to calculate is a rough guide to his or her intellectual ability.
Additions to the classic mental status that are helpful in this component of the exam are testing for visual praxis, the face-hand test, and the performance of a four-part command.
Excerpts From Chapter 2
Orientation
All normal people are oriented to time, place, and person. Time may be the most subtle component of this orientation. Most people in the modern world are oriented to time within 15 minutes. Thus, every person should be oriented to no less than 15 minutes. If you are generous, you can give a patient 30 minutes. Patients with dementia and parietal lobe lesions (particularly) on the right side may be disoriented. Some parietal lobe patients have very bizarre ideas of place orientation. They believe that their present location is related or connected to another location. Right parietal lobe defects cause difficulties with intra- and extrapersonal space. In general, place disorientation is associated with severe organic brain disease. The inability to recognize one’s person is seen with hallucinations and delusions in the acute state and chronically with severe dementia.
Memory
The memory function of the brain is essential for modern human life. It is subdivided by behavioral neurologists into explicit, that which you can consciously recall, and implicit, that which is registered without conscious intent and can only be examined under special circumstances. Working memory describes that body of knowledge that can easily be recalled and used for everyday living.
For the neurologist, memory is divided into inscription, consolidation, and long-term phases. Inscription is the first 30 seconds, which depends on the reverberating circuits of the hippocampus and utilizes acetylcholine as the neurotransmitter. Consolidation is the time period between these 30 seconds and 3 minutes. During this period, messenger RNA is synthesized, and the brain is on the way to long-term memory, which depends on protein synthesis. It is during these 30- to 3-minute intervals that consolidation can be interrupted by intrusions. Long-term memory is stored throughout the brain and is lost by the destruction of brain tissue. Classic short-term memory depends on the dorsal medial nucleus of the thalamus, the mamillary bodies, the fornix, and the medial hippocampus. The dorsolateral prefrontal cortex retrieves memories. Forgetting may be the unfolding of proteins that have been synthesized.
Examination Technique Demonstration
Fig. 2.3
Fig. 2.3 The face-hand test. The patient is being asked, “Where did I touch you?" If slightly confused (cortical level or demented), the patient reports, “On my face."
[Interpretation]
If a patient has minimal cognitive dysfunction or the examiner feels there is a slight diminution of alertness, the examiner performs the face-hand test. The examiner, in the middle of a conversation, touches his or her face and the patient’s hand. The examiner then asks the patient where he or she was touched, and the patient will answer “my face." No normal patient makes this error.