## 4 Discussion
[14] reported that a physiotherapy intervention including locomotor training and exercise programs improved balance, slowed the rate of gait decline, decreased wheelchair dependence, and decreased falls in a patient with mixed PSP. Similarly, [PERSON] et al. [40] showed improved gait, fall reduction, and enhanced balance following physical therapy in a person with PSP [40]. A systematic review by [PERSON] et al. [38], aiming to assess the efficacy of exercise and physical activity interventions in the PSP, concluded that exercise training may be beneficial [42]. A series of three case reports examined the effects of physical therapy and exercise interventions for patients with PSP reporting improvements in physical functional status [39]. Other studies demonstrate that exercise programs targeting muscle strengthening, balance, and mobility could improve functional outcomes and quality of life in this population [23; 43; 44; 45; 46]. The mechanisms by which exercise may benefit functional ability in PSP likely involve improvements in muscular strength, postural control, and mobility--all of which are typically impaired in this neurodegenerative disorder [46; 47]. The study's findings may indicate improvements in participant scores in HADS-D due to an exercise intervention in individuals with PSP. Regarding the effect of exercise on depression in people with PSP, this study is unique and innovative as there are no other studies studying this topic; however, these findings are supported by a body of evidence exploring the mechanisms by which physical activity can influence psychological well-being in chronic neurologic disorders [48; 49; 50]. A systematic review reported that exercise programs targeting balance, gait, and physical functioning often resulted in improvements in measures of depression and quality of life [50]. These positive changes may be attributed to psychological mechanisms that influence the participant's self-image [51]. Exercise plays a role in removing the patient from negative thoughts enhancing self-esteem through the theory of self-efficacy and self-mastery [52]. From a neurobiological perspective, exercise has been shown to increase the production and release of neurotransmitters such as serotonin, dopamine, and endorphins, which can have mood-enhancing effects and contribute to the reduction of anxiety and depressive symptoms [53; 54]. Additionally, physical activity can modulate the hypothalamic-pituitary-adrenal (HPA) axis, leading to decreased cortisol levels and improved regulation of the stress response system, which is often dysregulated in mood disorders [55]. Furthermore, exercise has been associated with increased hippocampal volume, enhanced neurogenesis, and improved connectivity in brain regions involved in emotional regulation, such as the prefrontal cortex and limbic system, all of which can contribute to the observed psychological benefits [56; 57]. This study found an improvement in the quality of life of the participant. This result is in agreement with the limited existing research on the potential benefits of exercise for quality of life in individuals with PSP. A systematic review [58] provided preliminary evidence that exercise programs may improve quality of life in different studies with a small sample of PSP patients [23; 43; 59; 60]. The current case study builds upon these findings, demonstrating that a 12-week exercise intervention targeting muscular strength, endurance, balance, and flexibility can lead to meaningful improvements in self-reported quality of life for an individual with early stage PSP. Exercise has been demonstrated to influence a variety of neurobiological mechanisms that can have profound impacts on neurological health and function. One of the key processes is neuroplasticity, which refers to the brain's ability to reorganize and adapt its connections and function in response to changes in behavior, environment, or neural processes [61].