Other cognitive disorders

Now we’ve looked at memory disorders, let’s go into the other cognitive disorders involved in Alzheimer’s disease. You may remember that we said Alois Alzheimer described some disorders in the patient he examined: memory disorders, as we said, but also temporal and spatial disorientation, comprehension disorders, aphasia, etc. Behavioural disorders and especially psychiatric disorders. So we must understand that the brain, ultimately, is a system of functional networks, and that system is used to transfer information from one point of the brain to another. 

The information is processed in specific modules. Here, for example. These are module factories that deal specifically with word understanding, language production, face recognition, temporal and spatial orientation, and memory, for example. The information processed by the auditory cortex, words for example, are transferred to regions that are involved with understanding the message that is heard. Later, this information is transferred to the region involved in language production, etc. These are extremely complex networks, because there are around 100 billion neurons in the brain, and each neuron can make up to 10,000 connections with the neurons around them. 

The network system is extremely complex and there are modules which process information. During Alzheimer’s disease, all these modules become disorganised, gradually I’d say. How words are understood, how language is produced, the ability to recognise faces, temporal spatial orientation, memory etc. so little by little, like the pillar of a cathedral that is about to collapse. Overall cognitive function will eventually be impaired. And the disease will stop developing. We’ve already seen this slide. 

The natural history of the disease starts firstly, as we said in the previous capsule, a gradual amnestic syndrome and then secondly, the appearance of disorders associated with the spread of lesions throughout the cerebral cortex. There will be language disorders, movement disorders, difficulty recognising faces and objects, that’s what we call agnosia. Behavioural disorders, character disorders, and a whole range of disorders that will gradually set in and affect the person’s autonomy. This loss of autonomy determines what in medicine we refer to as dementia. For doctors, dementia is obviously a very, very unfortunate term, But it does not mean the same in common parlance. Dementia simply means that a person loses their autonomy and become dependent. And for us doctors, a person with dementia requires help with everyday tasks. Dementia is a gradual phase of the disease. 

When the disease is diagnosed at dementia stage, it is based on this idea. Cognitive disorders must include a memory disorder which disrupts everyday activities, as stated previously. Cognitive tools can be used to measure cognitive disorders and these disturbances. They include MMS, temporal and spatial orientation, word list recall. These tools can be used as a guide to pinpoint a memory disorder. 

There are also studies on the verbal influence of naming, which suggests a language disorder. Then praxis which involves movements, drawing a clock. All this tells us that there are cognitive deficits that are more significant than just memory, which means the disease has gone beyond the prodromal phase and is probably already in the dementia phase. But most importantly there are autonomy markers in the subject’s daily life that characterise the dementia phase. Is the subject able to use the telephone? Do they use the phone on their own initiative? Can they only dial a limited list of numbers or perhaps they are unable to call but do answer? Perhaps they cannot even use the phone? Use of means of transport. Can they travel alone? Can they travel alone by taxi but not by bus, and so on? Taking medication. 

Can they take their medication alone or not? Do they need help taking their medicine and require someone to prepare them in advance or are they unable to take them alone even if they are prepared in advance? Ability to manage a budget alone, etc. So either the subject is completely autonomous, finds it easy to use the phone, public transport, take their own medicine, file their tax declaration, etc. That person is totally autonomous, or the subject may need help. And that may be a marker for Alzheimer’s disease. It takes some understanding, It takes adaptation. 

I usually say to my patients “Would you be able to meet me this evening at the Bar de la Marine in the port of Marseille?” Obviously, if they have coxarthrosis, they can’t. But if they have no motor problems, they should be able to, no what their age, take the train, go down Avenue de la Canebière and arrive at the Bar de la Marine. So you see, even a very old subject can be autonomous. Even an elderly subject can use public transport, can make an appointment wherever they need to go. These are markers of independence, and these markers of independence are markers of their state of autonomy. These are good markers for dementia.