Neurogenics - Key Terms

Ventricular system

Four connected, fluid-filled spaces inside the brain that make and circulate cerebrospinal fluid (CSF), which cushions and nourishes the brain. On a scan, enlarged ventricles can signal brain shrinkage (as in dementia) or a build-up of fluid (hydrocephalus, a possible complication after TBI).

Corpus callosum

The thick band of white matter that joins the left and right hemispheres, so the two halves of the brain can share information. A common site of damage in traumatic brain injury, where the brain is shaken inside the skull.

Frontal lobes

The front of each hemisphere. They support planning, decision-making, self-control, starting and stopping actions, and (on the left) speech production. With the temporal lobes, the areas most often damaged in traumatic brain injury.

Prefrontal cortex

The front-most part of the frontal lobes, and the main hub for executive function: setting goals, planning, monitoring and adjusting what we do. Damage here can leave language intact but make communication disorganised or poorly judged.

Temporal lobes

The sides of each hemisphere. They support hearing, understanding language (on the left), knowledge of words and concepts, and memory. Vulnerable in traumatic brain injury, and affected in Alzheimer's disease and some primary progressive aphasias.

Hippocampus

A curved structure deep inside each temporal lobe, essential for forming new memories of events and facts. Affected early in Alzheimer's disease, which is why recent events are usually forgotten first.

Limbic system

A group of structures deep in the brain, including the hippocampus and amygdala, involved in emotion, motivation and memory. It links feeling and remembering, which is why emotional events are usually remembered better than neutral ones.

Parietal lobes

The upper back of each hemisphere. They combine touch, body position and vision to tell us where things are in space. Right parietal damage can stop a person attending to the left side of space, even though their eyes work.

Middle cerebral artery

The main artery supplying the outer surface of each hemisphere, including much of the frontal, temporal and parietal lobes. The most common site of stroke. A left MCA stroke often causes aphasia

White matter

Bundles of insulated nerve fibres (axons) that carry signals between brain regions. Grey matter is where the nerve cell bodies sit. Easily stretched and torn when the brain moves inside the skull in traumatic brain injury.

Neural network

A group of brain regions, linked by white matter, that work together to support a skill such as attention or language. Explains why damage in different places can cause similar difficulties, and why right-hemisphere symptoms are hard to pin to one spot.

Focal vs diffuse damage

Focal: damage in one area, as in many strokes. Diffuse: damage spread across many areas, as in traumatic brain injury and most dementias. Focal damage tends to cause specific problems

Cognition

The mental processes we use to take in, store, use and act on information: attention, memory, reasoning, planning and more. In cognitive-communication disorders, these processes, not language itself, are where the difficulty starts.

Selective attention

Focusing on one thing while ignoring distractions, whether those are sights, sounds or your own intruding thoughts. Following one person's conversation in a noisy café or a busy ward.

Divided attention

Doing two or more things at once. It works best when the tasks use different processes and at least one is automatic. After a stroke, walking may stop being automatic, so walking and talking at the same time becomes hard.

Processing speed

How quickly a person can take in information, make sense of it and respond. Often slowed after brain injury: the person may understand perfectly well, but needs more time to do it.

Memory and working memory

Memory: taking in (encoding), storing and retrieving information. Working memory: the short-term workspace that holds information while you use it. Working memory lets you hold the start of a long sentence while you work out what it means.

Long-term memory

Information stored for years or decades, with almost unlimited capacity. It covers knowing facts and events, and knowing how to do things. The next three terms are its main parts: episodic, semantic and procedural memory.

Episodic memory

Memory for personal events: what happened, when and where. Usually the first type of memory to fail in Alzheimer's disease, with recent memories lost before older ones.

Semantic memory

General knowledge: the meanings of words, facts and concepts, such as knowing that a lemon is a citrus fruit. Fairly well kept early in Alzheimer's disease, then declines in the middle stages.

Procedural memory

Knowing how to do things, such as riding a bike or making a cup of tea. Learned through practice and used without conscious thought. Often kept until late in dementia. One man with Alzheimer's could still play golf well, but not remember the shot he had just hit.

Executive function

The "manager" processes we need for goal-directed behaviour that isn't automatic: starting, stopping, organising, sticking with a task, thinking flexibly and self-regulating. Supported by the prefrontal cortex

Inhibition

Stopping an automatic or unwanted response, thought or meaning. Without it, a person may say the first thing that comes to mind, or struggle to let go of the wrong interpretation of what they heard.

Self-awareness

Knowing your own strengths and difficulties, and noticing your own errors as they happen. Reduced awareness affects how willing a person is to take part in therapy, and how well they recover.

Cognitive-communication disorder

Difficulty communicating that comes from changes in cognition (attention, memory, executive function, social cognition) rather than from a loss of language itself. Common after right-hemisphere stroke, traumatic brain injury and dementia.

Pragmatics

Using language in context: what someone means, not just what they say. Includes adjusting how we speak for different listeners, settings and purposes, such as hinting politely rather than demanding.

Turn-taking

Knowing when to speak, when to listen, and how to hand the conversation back to the other person. Less appropriate turn-taking and eye contact are among the few consistent differences found in conversation after right-hemisphere damage.

Topic maintenance

Staying on topic, and shifting topic in ways the listener can follow. Tangential talk, drifting off the topic without the listener being able to follow, is common after right-hemisphere damage and TBI.

Inference

Working out meaning that is not directly stated: reading between the lines. "She looked with dismay at the flies around the basket of apples." Nobody says the apples are rotten, but we infer it.

Literal vs nonliteral meaning

Literal: the exact meaning of the words. Nonliteral: an intended meaning that differs, as in idioms, metaphor and sarcasm. "What a great day for a game!" said in pouring rain means the opposite.

Prosody

The "melody" of speech: changes in pitch, loudness, rhythm and timing that signal emphasis, questions, emotion and attitude. Compare "a WHITE house" with "a white HOUSE", or "No." with "No?"

Emotional prosody

Tone of voice that shows how a speaker feels or what attitude they hold: happy, sad, angry, bored, polite. More often affected after right-hemisphere than left-hemisphere damage, in hearing it, producing it, or both.

Social cognition

Understanding other people's thoughts, feelings and intentions, and using that understanding to make decisions during interaction. Includes recognising emotions, seeing things from another person's point of view, and empathy.

Theory of Mind

Understanding that other people have thoughts, beliefs and knowledge that differ from your own, and that these drive what they do. Without it, a speaker may give the listener too much or too little information, or use "he" and "she" without making clear who they mean.

Right-hemisphere damage

Damage to the right hemisphere, usually from stroke. Words and sentences usually hold up, but meaning in context, emotion and attention can be affected. The person does not have aphasia, yet communication can still break down, and the difficulties are easily missed.

Traumatic brain injury

Damage to the brain caused by a blow or jolt to the head, or by an object penetrating the skull. Common causes are road crashes, sport and falls

Dementia

An acquired, ongoing decline in several areas of cognition, severe enough to affect daily life, work and relationships, and not caused by delirium (acute confusion). Alzheimer's disease is the most common cause

Progressive vs non-progressive

Progressive: worsens over time, as in most dementias. Non-progressive: results from a single event and stays stable or improves, as in stroke and TBI. This shapes therapy goals: restoring and compensating, or maintaining and supporting for as long as possible.

Person-centred care

Care built around what matters to the person, who is an active partner in decisions about their goals and support. Includes whānau, whose knowledge and priorities help shape the plan.

Communication partner

Anyone the person communicates with: whānau, friends, carers, staff. Their skills and attitudes can help or hinder communication. You met communication partner training in aphasia. It matters just as much for people with cognitive-communication disorders.