Do you walk faster or do you slow down? So the gait explains how the psyche is

It is often said that the eyes are the window to the soul. But perhaps we should invent another proverb: 'tell me how you walk and I will tell you how you are'. At least on the psychological front, in fact, we should get used to studying our gait and pace to understand how much and how we are motivated to reach a goal. Because if we are happy we are inclined to speed up, perhaps jumping joyfully, trying to gain time to hug the person we are to meet. But if our mood is gloomy and we have no particular pleasure in reaching the goal, virtual or real, the path becomes slow, dragging. In short, by analysing how we move, we may get a picture of the psychological conditions. To guide the step and make it almost skip, as happens in films that tell love stories and magical encounters as a sign of happiness, there would in fact be dopamine. The neurotransmitter (heavily implicated in the perception of pleasure and reward management) would in fact underlie the unconscious mechanisms that guide gait patterns. An original study conducted by experts at the University of Colorado at Boulder, coordinated by Alaa Ahmed and Colin Korbisch, and published in Science Advances, opens the way to possible uses of gait analysis as an index of psychoneurological suffering, for example in depression or Parkinson's disease.

The investigation tried to reveal the brain pathways that control gait behaviour, based on a very curious experiment. Participants were asked to 'reach' a target on a computer screen with a kind of joystick. Reaching the target was linked to specific rewards, such as a simple flash of light and an acoustic signal. Result? The way in which these rewards exceeded, or failed to meet, expectations impacted on the participants' movement patterns, who had less or more drive to get closer to the target. Not only that: the presence of an expected or in any case unexpected reward would accelerate movement, with an effect imperceptible to the human eye but assessable thanks to tests showing a more rapid and marked response in terms of energy. In short: although we certainly can't say what lies behind this energy rush, which translated into our stride leads us to accelerate and almost walk on clouds towards the person we love or an unexpected destination, something happens. So dopamine is the medium that leads us to react by modifying our gait and movements, leading us to react immediately in the event of a positive 'surprise effect'.

'Movements are a window into the mind,' is Korbisch's comment in a note from the university. But limiting the observations to the neurotransmitter aspect alone is reductive. In fact, the working hypothesis envisages that in the future real gait analyses can be applied for the early diagnosis of health problems, given that there are many pathologies that can affect speed and stride length. Those suffering from depression, for example, tend to move slower than their age peers. The focus is therefore on reduced gait speed and physical and motor manifestations, in what is called 'psychomotor slowing' or bradykinesia. There are studies pointing out that those suffering from depression tend to walk significantly slower than those who do not suffer from the pathology, and on the other hand, it is precisely the slower pace that may become an index of risk for the development of the pathology. In this sense, given that depression is linked to a dysfunction of the dopaminergic system, particularly in anhedonia (inability to feel pleasure) and loss of motivation, the drop in dopamine may affect precisely the way one walks. Somehow the American research, by describing what happens in the presence of relative dopamine peaks that induce faster movements when one is happy or motivated, points to a way to catch early warning signs from simple gait observation.

On this front, moreover, other studies show that for the elderly, even pacing on a route with several bends could indicate the first signs of mild cognitive impairment, what experts call MCI (Mild Cognitive Impairment), a sort of index of increased risk of developing Alzheimer's disease. Moving on a route with more or less dry curves would require a kind of 'extra' cognitive capacity. This is according to a study published in the Journal of Alzheimer's Disease Reports and was conducted by experts from the College of Engineering and Computer Science at Florida Atlantic University. The scientists used special depth cameras to monitor the movements of as many as twenty-five joints, studying the gait of the study participants while performing two different walking tests, both in the straight and the curved path. The study showed that walking around bends was definitely more difficult and complex for those with mild cognitive impairment, because they suffered from what is technically called 'Mild Cognitive Impairment' or MCI. In particular, it was seen that considering different evaluation systems, from average speed to step cadence to foot position, when going round a bend the response for the elderly with mild cognitive impairment changed compared to the healthy. As if to say that the 'curve' imposed greater demands to be borne by those with small deficits. In short: the way one walks, the uncertainty and even the speed and amplitude of one's stride can become health signals.