The following article, “Four Ways to Spot Cognitive Decline Without a Formal Assessment, Clues are obvious if you know what to look for” has been written by Delia McCabe.
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“Cognitive decline is a complex and multifaceted phenomenon linked to structural and functional changes within neural tissue. Alzheimer’s and Parkinson’s disease are the two most common neurodegenerative diseases globally, and approximately eight million people in the US suffer from them currently. By 2050, the number of people living with these diseases is expected to double. (US Brain Foundation, 2024.)
Each disease has distinct symptoms, although some of them can overlap, and the diseases can co-occur, with 50 – 80% of people who experience Parkinson’s likely to experience Alzheimer’s. (Alzheimer’s Association US, 2024.)
Symptoms of Alzheimer’s disease include memory loss and having trouble thinking, while Parkinson’s is related to difficulty with fine motor skills and movement.
Unfortunately, cognitive decline starts approximately two decades before symptoms become apparent because our sophisticated brain tries valiantly to work around the structural changes. It creates detours and works harder to accomplish its tasks, making it hard for others to see what’s happening within the brain.
However, there comes a time when these symptoms can no longer be hidden, when others can see, firstly from physical changes and later from thinking processes and speech, that the brain is no longer working well.
Here are some of the signs that indicate cognitive decline is present.
Walking isn’t a simple process – but most of us do it thoughtlessly
Most people never think about walking. Even a young child standing up for the first time doesn’t consciously consider this epic moment in time. Something loved ones have eagerly awaited.
We don’t walk when we’re born because a variety of neural networks must be formed first.
In other words, standing, balancing, walking, and staying upright aren’t simple neural phenomena. They involve a variety of neurological and physical activities that must be coordinated between the nervous system, which includes the brain, and the musculoskeletal system.
Here’s a summary of the brain-body components involved in walking:
- Within the brain, the prefrontal cortex (PFC) is involved in the decision to stand and move, and the motor cortex initiates these voluntary movements.
- The basal ganglia also helps initiate, regulate, and stop movement, ensuring it’s a smooth process.
- The cerebellum coordinates balance and movement to ensure that steps are coordinated and smooth.
- Sensory feedback is required to ensure balance and walking can be adjusted according to the environment. It includes feedback from muscles, tendons, and skin. This feedback ensures the spinal cord and brain are kept informed about the body’s position and movement, which is critical for adjusting and coordinating movements.
- The parietal lobes, situated near the top and back of the brain, are involved in integrating sensory information to ensure we stay abreast of what’s happening in our environment and remain spatially oriented.
- Motor and sensory neurons transmit signals from the spinal cord to the muscles, causing them to contract and produce movement, and from the body back to the spinal cord and brain to provide feedback on the position and movement of limbs.
- Muscles in the legs, hips, and lower back contract in a coordinated manner to produce the movements that keep us upright and walking. Our arms are also involved, helping us stay balanced to move smoothly.
- The brain-stem integrates the sensory and motor information required to maintain balance and posture.
- Neuronal networks and central pattern generators (CPGs) are located within the spinal cord. These cells generate rhythmic patterns of activity, including those needed for walking.
- Proprioception is the sense we have of where our body is relative to our environment—the position our body is in. Proprioceptors in our muscles and joints provide continuous feedback to the central nervous system (CNS), which is essential to maintaining balance and coordination while walking.
- The vestibular system, located in our inner ear, provides information about the position of our head and our movements, which is also crucial for maintaining balance.
- Parkinson’s disease is linked to difficulty maintaining balance, slow reflexes, and movement, muscle rigidity, which impacts posture, and changes in gait, such as shuffling steps and reduced arm movement while walking. All the brain structures mentioned above are involved in these challenges.
A variety of processes ensure that walking is experienced as a repetitive and rhythmic activity, one which we don’t have to think about.
The brain and body work together to generate and fine-tune walking, with continuous sensory feedback that adjusts our movements to ensure smooth and efficient progress. (Gray, M, et al, 2021; Nishimura, H, et al, 2022; Castegnaro A, et al, 2023; Nishimura, H, et al, 2022; Lee, BC, et al, 2020; Principles of Neural Science, 2021.)
Walking is, therefore, a highly coordinated and integrated experience that relies on a complex interplay between the brain and body. This process requires a seamless integration of signals from various parts of the nervous system and body to maintain balance and adjust to environmental changes, including physical obstacles.
It’s easy to see that adverse changes in any of these neural structures will directly impact the complex, sensitive and sophisticated interplay between the brain and body aimed at staying upright to move and walk smoothly, with confidence. Without effort.
Facial expressions tell a story – one we may not want to share
Facial expression results from neural activity, whether we realize it’s happening or not. Minute micro-movements on our faces are picked up by others even when we try hard not to convey our emotions or thoughts.
Neuroanatomical changes accompanying cognitive decline lead to facial expression changes because the complex interplay between what we feel and think and how our faces change in relation to these internal phenomena becomes compromised.
- Cognitive decline can lead to less variation in facial expressions, with ‘mask-like’ or ‘flat’ expressions becoming apparent, wherein the face shows little expression and movement. This occurs because of changes in the PFC, which is responsible for emotional regulation and social behavior. In addition, negative changes in the cerebellum are related to motor control challenges linked to Parkinson’s disease, which can co-occur with other forms of dementia, including Alzheimer’s. These changes directly affect the motor control of facial muscles.
- Slower cognitive processing can lead to a noticeable delay in emotional or social cues being shared via facial expressions because neural tissue damage and inefficiency lead to increased cognitive load and time lags in response. The face isn’t timeously representing what the brain is processing because the process is slowed due to more cognitive effort being required to process and respond to thoughts, feelings and social cues.
- ‘Emotional blunting’ manifests in less expressive faces simply because it reflects a reduced intensity of emotions, again due to negative neuronal tissue changes. An overall reduction in emotional reactivity can include apathy and depression, which may manifest as a sad or neutral facial expression.
- Difficulty processing social cues leads to inappropriate or mismatched emotional responses shared via facial expressions. Various cognitive processes need to function simultaneously to facilitate recognizing and interpreting others’ facial expressions, including input from the PFC, which support the appropriate response.
- Specific neurological conditions can lead to involuntary facial movements or ‘tics,’ which become more pronounced in advanced stages of cognitive decline.
- Cognitive decline can impact muscle tone in the face and lead to either muscle flaccidity or rigidity, which affects the ability to form expressions.
- Individuals who struggle to understand their surroundings and experiences can exhibit facial expressions of agitation, anxiety, or confusion.
- Individuals experiencing cognitive decline may limit their social interactions or withdraw from them due to difficulties in communication and understanding social cues. This behavior leads to fewer opportunities for facial expressiveness as social interactions typically prompt varied expressive responses.
These factors collectively contribute to the characteristically reduced and often inappropriate facial expressions observed in individuals experiencing cognitive decline.
Changes in facial expression are influenced directly by underlying changes in neural tissue and connectivity. As each brain is different and a variety of factors influence neuroanatomical decline, effects can vary widely among individuals. (Jiang Z, et al, 2022; Pietschnig J, et al, 2016; Principles of Neural Science, 2021.)
‘Please repeat that … it wasn’t very clear.’
Slurred speech may be another symptom of cognitive decline, which occurs for similar reasons to impaired walking and lack of facial expressiveness.
- The motor cortex in the frontal lobe directs muscle movements that initiate and coordinate the movement of the mouth, tongue, and throat. Information from Broca’s area and a band of nerves (arcuate fasciculus) that link this area to Wernicke’s area are also involved in initiating speech and work with the motor cortex to ensure words are articulated clearly. The cerebellum, also involved in walking, coordinates voluntary muscle movements like opening and closing the mouth.
- Dysarthria is a speech disorder caused by a weakening of the muscles that govern speech. It’s a common condition in Parkinson’s disease, and symptoms include changes in vocal sound and tone, speech that’s either too fast or too slow, and vocal tremors.
‘ … individuals with dysarthria from Parkinson’s may be most affected by overall motor function, while participation in life situations may be most influenced by decreased conversational intelligibility … ’ (Spencer, KA, et al, 2020.)
- Although we don’t think about speaking and breathing while talking, these two activities must be coordinated to allow for smooth mouth and tongue movements. Negative brain changes can prevent these two seemingly simple activities from being coordinated optimally.
- Medications prescribed for cognitive decline, including Parkinson’s disease, can cause involuntary muscle movements (dyskinesia), which can impact muscles involved in speech. Such medication can also affect alertness, which may impact speech. Managing tremors with medication can lead to a dry mouth, which can impact speech, and the timing of medication can lead to adverse changes in speech as the medication wears off. (Spencer, KA, et al, 2020; De Stefano, 2021; Principles of Neural Science, 2021.)
‘Please repeat that … it doesn’t make sense.’
When we speak, we articulate what we’re thinking and how we feel. When we converse with others, we need to keep track of what they’re saying and what we’re saying so that we can respond accordingly and appropriately.
Such responses tend to be naturally logical, too, because they’re related to the cognitive process of analyzing and assessing information and data and then applying strict principles of validity to what we perceive and how we respond to it. For example, if someone mentions the weather in passing and we start talking about our breakfast, it’s easy to see a disconnect between these two topics. We didn’t follow a logical progression to get to the breakfast comment.
The cognitive process of applying logic to what we perceive and how we respond to such isn’t confined to isolated brain regions – it’s the result of the sophisticated interaction of distributed neural networks.
- Neuroplasticity is how the brain changes itself, which relies on the ability of neurons to quickly form new connections between themselves. It allows the brain to follow a thought and respond to it logically. Obviously, if this process cannot unfold optimally, the result is likely to be a disconnect between what is heard, perceived and how we respond to it. Keep in mind, too, that if the input and perception are compromised, it’s unlikely the output and the response will be logical.
Read more about neuroplasticity here
The ability to adapt to new information and environments is also linked to neuroplasticity, which underpins ‘cognitive flexibility.’ Neuroplasticity is important because as new information comes to light and situations change, so too should responses.
- The PFC plays a critical role in logical thinking, which is part of decision-making and problem-solving. The PFC is often called the CEO of the brain because it’s involved in executive functions—the cognitive processes that lead us forward, such as planning and consequential thinking (‘what’ll happen if I do/say this?’)—and inhibits inappropriate emotional responses to situations.
The PFC is also involved in semantics – making meaning of the words we hear.
When the PFC isn’t working optimally, a person can quickly become angry and unreasonable because the process of inhibiting emotional outbursts is compromised. Naturally, this extends to other behavioral challenges too.
- Along with the PFC, our working memory is involved in how we make sense of what we’re saying and hearing in real-time. The job of our working memory is to hold onto and manipulate information as we hear it and speak about it. We can’t follow or contribute logically to a conversation when our working memory cannot hold an idea long enough to articulate what we think or feel about it.
- The ability to consolidate memories by moving them from short-term to long-term storage is also critical to brain function and being able to speak logically because we use such memories to inform reasoning and make decisions. We may have to draw on information from the past to make a point about what we are discussing now. For example, it would be impossible to have a logical conversation with someone who can’t recall what was discussed last week when those facts are pertinent to the current conversation. Unfortunately, cognitive decline can leave people very able to recall memories from decades ago yet be unable to recall what they did yesterday.
Unfortunately, the advantages of experience, gaining knowledge and acquiring wisdom, all of which occur through a life well-lived and exist in our long term memory, are lost when the brain is in decline. These cognitive capacities live inside neurons and their connections and when they wither and die we lose them.
- The medial temporal lobes and the hippocampus are brain regions involved in memory, including ‘semantic’ memory, which is a type of long-term memory. Semantic memory includes concepts, numbers, and words that we need to be able to recall easily and use to converse with ease. Damage to these areas leads to challenges in recalling, using, and understanding such words.
‘ … overall reaction time for word retrieval (controlling for psychomotor slowing) was the best predictor of spontaneous word finding difficulty and executive function decline, suggesting processing speed as the key factor, and that verbal reaction time may be an important clinical measure … ’ (Wei, HT, et al, 2024.)
- The anterior cingulate cortex (ACC), located in the frontal part of the cingulate cortex, is involved in error detection and emotional regulation. When the brain can detect a flaw in a flow of information or a discussion, it can quickly return to a logical process of reasoning.
The ACC is also involved in sustaining attention, which is a necessary skill in following a logical discussion and completing a task.
- Neurotransmitters, such as dopamine and serotonin, influence cognition and emotion, including logical thinking, by modulating neural activity and synaptic transmission. When neurons become compromised, their ability to synthesize neurotransmitters, use them optimally, and, therefore, communicate with each other is compromised too. This results in a negative cascade effect within neural networks, with effects reverberating across the brain and body.
Using words to convey what we’re thinking about and how we feel is, therefore, a complex process that relies on both specific neurophysiological structures that integrate our thoughts and emotions in a logical sequence and the physical structures that allow speech to be formed—our tongue, mouth, throat, and other corresponding muscles.
Illogical and slow responses, which are difficult to follow and understand in conversation or, generally, when speaking, are caused by the combined output and interaction of these structures. (Shuren JE and Grafman J, 2022; Xu Y, et al, 2012; Wei, HT, et al, 2024; Principles of Neural Science, 2021.)
Many people ironically still expect a person exhibiting signs of cognitive decline to follow a logical and rational thought process. Although the person attempting to converse may be aware of the other’s cognitive decline, they may still be swept up into a truly senseless argument, forgetting that rationality is not possible in a malfunctioning brain.
Adult children of parents or partners of those exhibiting signs of cognitive decline often battle with cognitive dissonance, as it’s easy to forget they’re not talking to the same person they used to talk to, whose brain used to function well.
I recall working with a person many years ago who continued to get into arguments with his aging mother, who had not yet been diagnosed with Alzheimer’s but whom he knew wasn’t able to drive safely anymore. She kept insisting that she was able to drive despite a recent history of the opposite, and he had to stop arguing with her and simply remove her car keys from her handbag.
Regardless of emotion, never take for granted that the brain you’re conversing with is functioning optimally. It’s an assumption that can cost you dearly.
In summary, movement, balance, posture, facial expression, speech and logical reasoning are all interconnected activities simply because the body and brain are interconnected. Although specific areas in the brain may become compromised first, because neurons and the networks they’re part of are all connected, if one area becomes compromised, it will eventually impact others.
Although there are a number of tests that have been developed to assess cognitive decline, a few may be used in combination to highlight specific symptoms and confirm what is suspected. However, if you’re observant, you can see the symptoms of cognitive decline without such tests.
Cognitive decline is one of the worst experiences a human can endure. However, it’s often experienced most harshly by those who observe it over time because the person experiencing it becomes less aware of it simply due to the nature of the challenge.
Unfortunately, to date, we haven’t found a cure for this dehumanizing experience, although a growing body of research is examining how we can prevent cognitive decline. In future posts I will address some of this research.”
As the brain is not separate from the rest of our body, it is becoming increasingly hypothesised that exposure to toxins, nutritional deficiencies, impaired circulation, chronically elevated blood sugar levels or insulin resistance, physical trauma, and EMF exposure all contribute to health problems, including impairment of brain function. Read more on these here in my website.
References
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De Stefano A, et al (2021) Changes in Speech Range Profile Are Associated with Cognitive Impairment. Dement Neurocogn Disord;20(4):89-98.
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Gray M, et al (2021) Cognitive decline negatively impacts physical function. Exp Gerontol;143:111164.
Jiang Z, et al (2022) Automated analysis of facial emotions in subjects with cognitive impairment. PLoS ONE 17(1): e0262527.
Lee BC, Choi J, Martin BJ (2020) Roles of the prefrontal cortex in learning to time the onset of pre-existing motor programs. PLoS One;15(11):e0241562.
Nishimura, H, et al (2022) Detection of cognitive decline by spinal posture assessment in health exams of the general older population. Sci Rep 12, 8460.
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Shuren JE, Grafman J (2022) The Neurology of Reasoning. Arch Neurol;59(6):916–919.
Spencer, KA, et al (2020). Predictors of Health-Related Quality of Life and Communicative Participation in Individuals with Dysarthria from Parkinson’s Disease. International Journal of Neurodegenerative Disorders;
Wei, HT, et al (2024) Cognitive components of aging-related increase in word-finding difficulty. Aging, Neuropsychology, and Cognition, 1–32.
Xu Y, et al (2012) Neurotransmitter receptors and cognitive dysfunction in Alzheimer’s disease and Parkinson’s disease. Prog Neurobiol;97(1):1-13.
https://www.americanbrainfoundation.org/disease-connections-alzheimers-and-parkinsons/ (cited 8 July, 2024)
https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia/parkinson-s-disease-dementia (cited 9 July, 2024)
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