Idiopathic Parkinson's Disease: Key Characteristics

This question tests recognition of the motor and non-motor features of Idiopathic Parkinson's Disease (IPD). The correct combination is 2, 3 and 4.

Statement Analysis

• Statement 1: Motor symptoms are almost always initially symmetrical — Incorrect. A hallmark clinical feature of Idiopathic Parkinson's disease is asymmetric onset of motor symptoms (tremor, rigidity, bradykinesia typically begin on one side of the body and remain more pronounced on that side even as disease progresses). Symmetrical onset from the start is atypical for IPD and should raise suspicion of an atypical parkinsonian syndrome (e.g., drug-induced parkinsonism, multiple system atrophy, or progressive supranuclear palsy) rather than idiopathic Parkinson's disease. Hence this statement is false and correctly excluded from the answer.
• Statement 2: Non-motor symptoms include hyposmia and constipation — Correct. Non-motor features are well recognised in IPD and often precede motor symptoms by years. Hyposmia (reduced sense of smell) and constipation (due to enteric autonomic dysfunction) are among the most well-documented premotor/non-motor manifestations, along with REM sleep behaviour disorder and depression.
• Statement 3: Cognition is spared in early disease — Correct. In the early stages of IPD, cognitive function is generally preserved, and patients typically present with isolated motor complaints. Cognitive decline and dementia, when they occur, tend to appear later in the disease course (after several years), which helps distinguish IPD from Dementia with Lewy Bodies, where cognitive impairment appears early alongside or before motor features.
• Statement 4: Speech may become softer and indistinct — Correct. Hypophonia (soft speech volume) and dysarthria with indistinct articulation are well-known motor manifestations of Parkinson's disease, resulting from bradykinesia and rigidity affecting the muscles of speech and respiration.

Why the Other Options Are Wrong

• 2 and 3 only: Omits statement 4, which is a correct and well-established feature (hypophonia/soft speech) of IPD.
• 1 and 4 only: Incorrectly includes statement 1 (symmetrical onset is not typical of IPD) and omits the correct statements 2 and 3.
• 1, 3 and 4: Incorrectly includes statement 1; symmetrical, rather than asymmetrical, onset is not a feature of IPD.

Conclusion

Since statements 2, 3, and 4 are accurate descriptions of Idiopathic Parkinson's disease and statement 1 is false (IPD classically presents with asymmetric, not symmetric, onset of motor symptoms), the correct answer is 2, 3 and 4.