Cognitive Rehabilitation as a Balance Rehabilitation Strategy in Patients With Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder. PD is characterized by motor symptoms, such as bradykinesia, tremor, and rigidity. Although balance impairment is characteristic of advanced stages, it can be present with less intensity since the beginning of the disease. Approximately 60% of PD patients fall once a year and 40% recurrently These falls may be correlated with the inability to achieve compensatory movements to regain balance when their center of gravity tends to swing outside their range of stability, which is reduced in this disease. On the other hand, cognitive symptoms affect up to 20% of patients with PD in early stages and can even precede the onset of motor symptoms. There are cognitive requirements for balance and can be challenged when attention is diverted or reduced, linking a worse balance and a higher probability of falls with a slower cognitive processing speed and attentional problems. Cognitive rehabilitation of attention and processing speed can lead to an improvement in postural stability in patients with Parkinson's. The investigators present a parallel and controlled Randomized Clinical Trial (RCT) to assess the impact on balance of a protocol based on cognitive rehabilitation focused on sustained attention through the NeuronUP platform (Neuronup SI, La Rioja, España) in patients with PD. This therapy opens the possibility of new rehabilitation strategies for prevention of falls in PD, reducing morbidity and saving costs to the health system.

Parkinson's disease (PD) is the second most common neurodegenerative disorder. This disease is characterized by motor symptoms, such as bradykinesia, tremor, and rigidity. Non-motor symptoms such as cognitive impairment, anosmia, sleep disorders, or depression are also part of the disease, and although their prevalence is very high, non-motor symptomsare often underdiagnosed.

One of the cognitive characteristics in PD is the slowness in the processing of information, which includes deficits in processing speed and attention, cognitive inflexibility, and forgetfulness. These symptoms may appear from the initial stages of the disease.

Approximately 60% of PD patients fall once a year and 40% do so regularly. These falls may be correlated with the inability to achieve compensatory movements to regain balance when their center of gravity generally oscillates outside their limits of stability (LOS), which is reduced in this disease. Some authors point out that reaction times and processing speed may be a marker of postural instability since a reduced speed is associated with difficulty in making turns. This is in line with Pantall's findings, indicating that cognitive function and postural control normally progressively worsen with disease progression.

The relationship between cognitive impairment and postural instability in PD patients may be specific for tasks that assess the dorsolateral prefrontal cortex and its frontal-subcortical connections. The main cognitive functions whose affectation would influence a worse balance and gait performance would be attention and executive functions. Varalta et al specified that balance is related to executive functions and attention, while functional mobility is more related to cognitive impairment, verbal fluency, and attentional capacity.

Some authors point out that within the executive functions the component with the greatest weight in this relationship would be the inhibitory control. Dual-task performance has also been established as a good indicator of falls in patients with early-stage PD and no previous history of falls. The studies that carried out a one and a half years follow-up of the participants concluded that the deterioration of executive functions acts as a predictor of future falls in patients with PD.

Cognitive rehabilitation through neurorehabilitation platforms and neuropsychological rehabilitation in patients with Parkinson's disease has shown to be effective in improving processing speed, attention, and executive functions.

Although the relationship between cognitive deficits and postural stability seems to be demonstrated, the investigators have not found studies that, through cognitive rehabilitation, seek a stability improvement.

The investigators working hypothesis is that the group that receives rehabilitation of the speed of information processing and sustained attention will improve their postural stability compared to the group that does not undergo any therapy.

Eligibility Criteria:
Inclusion Criteria:

* Idiopathic Parkinson's disease (diagnosed according to the UK Parkinson´s Disease Society Brain Bank criteria).
* Stage \<III Hoehn-Yahr with no obvious motor fluctuations.

Exclusion Criteria:

* Visual-perceptual difficulties.
* Peripheral sensory disturbances due to polyneuropathy.
* Cerebellar alterations.
* Severe cognitive impairment (MoCA \<24).
* Moderate or severe active depression (BDI\> 14).
* Dependence (mRS\> 3).
* Dopaminergic medication changes in the last 30 days.
* Structural changes MRI Severe comorbidity (cancer, severe COPD ...).
* Atypicality data for idiopathic PD.