Early Detection of Parkinson's Disease: An Intelligent Diagnostic Approach

Introduction

Parkinson’s Disease (PD) is a progressive, neurodegenerative disorder that basically effects the motor system of a human being which causes physical problems such as shaking, stiffness, and difficulty in walking, balancing and coordinating movements (Parkinson’s disease) (Mohamed, 2016). PD is basically central nervous system oriented disease, occurred due to disintegration of a region called “substantia nigra” in the thalamic region of human brain (Figure 1).

Figure 1.

Location of Substantia nigra in human brain (Parkinson’s disease)

This substantia nigra secretes a neurochemical named “dopamine” which is responsible for transmitting of neural signals to the different organs and parts of the human body (Figure 2).

Figure 2.

Comparison of neurons of normal and PD-affected persons (Parkinson’s disease)

With increase of dopamine loss in the course of time, the PD progresses gradually which ultimately leads to mental disorder such as thinking and behavioral disability, dementia, depression and anxiety, sleep disorder, lack of emotions etc. (Olanrewaju, Sahari, Musa, Hakiem, 2014).The various movement-difficulties experienced by PD-suffered individuals are collectively addressed by the term “Parkinsonism”. It has been revealed in a recent survey in 2015 that approximately there are 7-10 million people are suffering from PD in the worldwide. The occurrence of PD is much higher in case of elderly people, typically over the age of 60 years; with a male-to-female ratio of 3:2 (Parkinson’s disease) (Mohamed, 2016).

Parkinsonism is defined by “Bradykinesia”, a spectrum of movement disorder, commonly known as hypokinesia. Bradykinesia refers to a situation when a person’s movement or initiation of voluntary body-movement has slowed down, due to disruption in basal ganglia of human brain, with an increasing reduction of speed and range of repetitive actions (Parkinson’s disease). Bradykinesia is considered to be one of the four key symptoms of PD, along with rigidity, tremor, and postural instability (Pahwa and Lyons, 2013).

There is no remedy or prevention available for PD. However, PD can be controlled if diagnosed at an early stage. Basically, in clinical diagnosis, PD is diagnosed with the presence of two or three of the four key motor-sign symptoms, namely tremor, rigidity, Bradykinesia and postural disability. The risk factor of PD tends to increase with the age of an individual. Most of the motor-sign symptoms are remained unnoticed as they are similar to the aging-sign of an elderly individual. By early detection of PD, its effect can be minimized on the affected person and proper treatment can be offered. One of the advanced and recent method of early detection of PD is using of biomarkers. Biomarker namely DaTscan, which is approved by FDA, to be used in diagnosis test of PD. The DaTscan (Ioflupane ¹²³I injection, also known as phenyltropane) is a radiopharmaceutical agent which is injected into a patient’s veins in a procedure referred to as SPECT imaging (DAT-scanning) (DaTSCAN, 2011). It is used to detect the loss of nerve cells in the striatum region of human brain, specifically the cells that release dopamine. However, the use of DaTscan also carries risk of allergic reaction, especially in case of pregnant women (DaTSCAN, 2011). Hence, there is a demand for development of intelligent data mining techniques which can provide efficient and early detection and diagnosis of PD, without risking the side-effects of treatments. A number of research works have been proposed in recent years based on this idea (Olanrewaju, Sahari, Musa, Hakiem, 2014) (Alemami and Almazaydeh, 2014) (Mohamed, 2016) (Caliskan, Badem, Baştürk, Yüksel, 2017) (Anita and Aruna Priya, 2016).