Parkinson’s disease
Parkinson’s disease or PD is a neurodegenerative condition involving the progressive damage of the central nervous system and affects mostly the movement of patients. The early symptoms of the disorder include motor symptoms such as slowness of movement, rigidity, tremor and walking difficulty. However, later on the behavioural issues might emerge, including agitation, apathy, hypersexuality, acting on impulses, stereotypic movements, REM sleep behavioural disorder, abuse of medications, pathological gambling, etc. (Bloem et al., 2021). The patients usually suffer from hallucinations, psychoses, anxiety and depression disorders, with increasing difficulty in experiencing and recognising emotions that impair their behaviour and might affect psychosocial issues in the patients.
The neurobiology of the disease includes the degeneration of the dopamine neurons at the nigrostriatal and the deposition of specific proteins termed as α-synuclein in the intraneuronal Lewy inclusions. The pathology begins in the lower medulla oblongata, as lesions form in the dorsal motor nucleus and worsen, and as time progresses, inclusions form in the lower raphe nuclei and Lewy neurites are formed. The cognitive status initially correlated with the neurobiological stage and finally, the motor activities of the patient are affected, causing bradykinesia, tremor, postural instability and rigidity (Weintraub et al., 2022).
Cognitive and emotional functioning of patients are altered as well due to the action of the Lewy neurites deposition and lack of dopamine in the central nervous system. The visuospatial function, executive function, working and attention memory are collectively affected in the cognitive domain (Bloem et al., 2021). Emotional dysregulation is another identified issue in Parkinsonism as depressed mood, fatigue, impulsiveness, decreased or increased appetite, feelings of guilt, suicidal ideations, etc. are some of the emotional responses or symptoms exhibited by patients of Parkinson’s disease. The disease severity also translated to impaired assessment, perception, and recognition of emotional expressions (Weintraub et al., 2022).
The current methods for treating Parkinson’s disease include pharmacological treatment options mostly, with a certain surgery opted in some cases termed as deep brain stimulation. The pharmacological management targets at increasing the level of dopamine in the brain aiding in controlling the non-movement symptoms and presenting effect on the brain chemicals such as neurotransmitters. The non-pharmacological treatment options include lifestyle changes, practising meditation, yoga, etc. to improve the cognitive and emotional dysregulations associated with the disease. The primary treatment of the usage of levodopa, and other agents include dopamine agonists, COMT inhibitors, anticholinergics, adenosine 2A antagonists, amantadine, etc. The levodopa agent being the most effective drug, acts to replenish the lowered supply of dopamine as levodopa is the precursor molecule (Gandhi & Saadabadi, 2023). The drug is used in combination with carbidopa to prevent its early conversion to the dopamine form outside the brain. Amantadine is prescribed for treating the episodes of speaking, walking, moving difficulties, etc. The dopamine agonists are dopamine replacement therapy with specific action on dopamine receptors (Choi & Horner, 2023). All these pharmacological management options are efficient to some extent and future studies are yet to be conducted to determine proper treatment interventions for Parkinson’s disease.
References
Bloem, B. R., Okun, M. S., & Klein, C. (2021). Parkinson’s disease. The Lancet, 397(10291), 2284-2303. https://doi.org/10.1016/S0140-6736(21)00218-X
Weintraub, D., Aarsland, D., Chaudhuri, K. R., Dobkin, R. D., Leentjens, A. F., Rodriguez-Violante, M., & Schrag, A. (2022). The neuropsychiatry of Parkinson’s disease: advances and challenges. The Lancet Neurology, 21(1), 89-102. https://doi.org/10.1016/S1474-4422(21)00330-6
Gandhi KR, Saadabadi A. Levodopa (L-Dopa) [Updated 2023 Apr 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482140/
Choi J, Horner KA. Dopamine Agonists. [Updated 2023 Jun 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551686/
