Cognitive Disorder.
1. Introduction
Cognitive disorders are mental health conditions that primarily affect a person’s ability to think,
remember, reason, learn, and make decisions. These disorders arise due to brain dysfunction rather
than emotional or psychological stress alone. Cognitive disorders are common in medical, surgical,
psychiatric, and elderly populations and have significant impact on daily functioning, independence, and
quality of life.
In modern classifications (DSM-5), cognitive disorders are referred to as Neurocognitive Disorders.
2. Cognitive Functions
Cognition refers to mental processes involved in acquiring knowledge and understanding. The main
cognitive domains include:
Attention – ability to focus and sustain concentration
Memory – ability to store and recall information
Orientation – awareness of time, place, and person
Language – comprehension and expression of speech
Executive function – planning, judgment, problem-solving, and decision-making
Perception – interpretation of sensory information
Learning ability – acquisition of new information
Impairment in one or more of these domains leads to cognitive disorder.
3. Classification of Cognitive Disorders
3.1 Delirium
Definition:
, Delirium is an acute, transient, and reversible disturbance of consciousness and cognition, characterized
by impaired attention and awareness.
Key Features:
Sudden onset (hours to days)
Fluctuating course (worse at night – sundowning)
Reduced attention and concentration
Disorganized thinking
Altered level of consciousness
Visual hallucinations and illusions are common
Common Causes:
Infections (UTI, pneumonia, sepsis)
Electrolyte imbalance
Dehydration
Hypoxia
Drug intoxication or withdrawal (alcohol, sedatives)
Post-operative states
Metabolic disorders
Types of Delirium:
Hyperactive delirium (agitation, restlessness)
Hypoactive delirium (lethargy, withdrawal)
Mixed delirium
1. Introduction
Cognitive disorders are mental health conditions that primarily affect a person’s ability to think,
remember, reason, learn, and make decisions. These disorders arise due to brain dysfunction rather
than emotional or psychological stress alone. Cognitive disorders are common in medical, surgical,
psychiatric, and elderly populations and have significant impact on daily functioning, independence, and
quality of life.
In modern classifications (DSM-5), cognitive disorders are referred to as Neurocognitive Disorders.
2. Cognitive Functions
Cognition refers to mental processes involved in acquiring knowledge and understanding. The main
cognitive domains include:
Attention – ability to focus and sustain concentration
Memory – ability to store and recall information
Orientation – awareness of time, place, and person
Language – comprehension and expression of speech
Executive function – planning, judgment, problem-solving, and decision-making
Perception – interpretation of sensory information
Learning ability – acquisition of new information
Impairment in one or more of these domains leads to cognitive disorder.
3. Classification of Cognitive Disorders
3.1 Delirium
Definition:
, Delirium is an acute, transient, and reversible disturbance of consciousness and cognition, characterized
by impaired attention and awareness.
Key Features:
Sudden onset (hours to days)
Fluctuating course (worse at night – sundowning)
Reduced attention and concentration
Disorganized thinking
Altered level of consciousness
Visual hallucinations and illusions are common
Common Causes:
Infections (UTI, pneumonia, sepsis)
Electrolyte imbalance
Dehydration
Hypoxia
Drug intoxication or withdrawal (alcohol, sedatives)
Post-operative states
Metabolic disorders
Types of Delirium:
Hyperactive delirium (agitation, restlessness)
Hypoactive delirium (lethargy, withdrawal)
Mixed delirium
