Nervous System MCQ for RRB & SSC and other Competitive exams
71
What is neuropathic pain?
✓ Answer:
B
Pain arising from damage or dysfunction of the nervous system itself - characterised by burning, shooting, or electric pain with allodynia and hyperalgesia
Neuropathic Pain arises from direct damage to or dysfunction of the somatosensory nervous system (peripheral nerves or CNS) - unlike nociceptive pain (from tissue damage). Characteristics: Burning, shooting, electric shock-like, stabbing pain. Allodynia = Pain from normally non-painful stimuli (e.g., light touch). Hyperalgesia = Exaggerated pain response to painful stimuli. Spontaneous pain = Pain without any apparent stimulus. Causes: Diabetic peripheral neuropathy (most common), Post-herpetic neuralgia (after shingles), Trigeminal neuralgia, Phantom limb pain, Complex Regional Pain Syndrome (CRPS), MS, and spinal cord injury. Treatment: Amitriptyline (TCA), Duloxetine (SNRI), Pregabalin/Gabapentin (calcium channel modulators), and Topical lidocaine/capsaicin. Standard analgesics (NSAIDs, paracetamol) are often ineffective.
72
What is motor neuron disease (MND)?
✓ Answer:
C
A progressive neurodegenerative disease affecting both upper and lower motor neurons causing wasting, weakness, and eventually respiratory failure
Motor Neuron Disease (MND) is a group of progressive neurodegenerative disorders affecting both UMNs and LMNs. Most common form: ALS (Amyotrophic Lateral Sclerosis) - Lou Gehrig's disease. UMN features: Spasticity, hyperreflexia, Babinski sign. LMN features: Wasting, fasciculations, weakness. Spares: Sensation, cognition (usually), eye movements, bladder/bowel. Fatal - usually within 3-5 years (respiratory failure). Famous patients: Stephen Hawking (physicist), Lou Gehrig (baseball player). ~10% are familial (SOD1, C9orf72 gene mutations). Treatment: Riluzole (modestly slows progression - glutamate antagonist), supportive care, ventilation, PEG feeding. NICE approved Tofersen (antisense oligonucleotide) for SOD1-ALS.
73
What is the significance of the Babinski sign?
✓ Answer:
C
Extension of the big toe and fanning of other toes when the lateral sole is stroked - normal in infants but indicates upper motor neuron lesion in adults
The Babinski Sign (Plantar Response): The lateral sole of the foot is stroked from heel to toe. Normal (adults): Toes flex downward (plantar flexion) = negative Babinski. Abnormal (Babinski positive): Big toe extends upward (dorsiflexion) + other toes fan outward = indicates Upper Motor Neuron (UMN) lesion. Normal in infants (up to ~18 months) because the corticospinal tract is not yet fully myelinated. Positive Babinski in adults = pathological UMN lesion (stroke, MS, spinal cord compression). Named after Joseph Babinski (French-Polish neurologist, 1896). Other signs of UMN lesion: Hyperreflexia, clonus, spasticity, weakness. Essential part of every neurological examination.
74
What is the trigeminal nerve (CN V) responsible for?
✓ Answer:
C
Sensation from the face and motor control of mastication (chewing) muscles
The Trigeminal Nerve (CN V) is the largest cranial nerve and has both sensory and motor functions. Three divisions: V1 (Ophthalmic) = Sensory - forehead, scalp, nose, cornea (corneal reflex - afferent limb). V2 (Maxillary) = Sensory - cheeks, upper lip, upper teeth, palate. V3 (Mandibular) = Sensory - lower jaw, lower teeth + Motor - muscles of mastication (masseter, temporalis, pterygoids). Trigeminal Neuralgia: Sudden, severe, electric shock-like pain in the face - one of the worst pain syndromes known. Triggered by light touch (eating, talking). Treatment: Carbamazepine (first-line). Herpes zoster (shingles) commonly affects V1 division causing painful rash around eye (Herpes zoster ophthalmicus).
75
What is Huntington's disease?
✓ Answer:
C
A genetic autosomal dominant neurodegenerative disease causing involuntary movements (chorea), psychiatric symptoms, and dementia
Huntington's Disease (HD) is an autosomal dominant neurodegenerative disease caused by an expanded CAG trinucleotide repeat (>36 repeats) in the HTT gene on chromosome 4, producing mutant huntingtin protein that is toxic to neurons. Anticipation: Number of repeats increases with each generation causing earlier onset in offspring. Primarily affects the striatum (caudate nucleus) and later the cerebral cortex. Features (typically onset 30-50 years): Chorea (involuntary, jerky, dance-like movements), Psychiatric (depression, anxiety, personality change - often precede motor symptoms by years), Dementia (progressive cognitive decline), and Dysphagia (aspiration risk). No cure. Treatment: Tetrabenazine (depletes dopamine - reduces chorea), antidepressants, antipsychotics. Fatal within 15-20 years of onset. Genetic testing available - raises ethical dilemmas.
76
What is the Glasgow Coma Scale (GCS)?
✓ Answer:
C
A scale used to objectively assess consciousness level based on eye opening, verbal response, and motor response
The Glasgow Coma Scale (GCS) was developed at the University of Glasgow (Teasdale and Jennett, 1974) to standardise assessment of consciousness level after brain injury. Three components (mnemonic: EMV - Eye, Motor, Verbal): Eye Opening (E) = 4 Spontaneous, 3 To voice, 2 To pain, 1 None. Verbal Response (V) = 5 Oriented, 4 Confused, 3 Words, 2 Sounds, 1 None. Motor Response (M) = 6 Obeys commands, 5 Localises, 4 Withdraws, 3 Flexion, 2 Extension, 1 None. Total score: 3-15. Maximum = 15 (fully conscious). Minimum = 3 (deep coma). Score <=8 = severe brain injury (consider intubation). Score 9-12 = moderate injury. Score 13-15 = mild injury. Used in ICU, trauma, and emergency medicine worldwide.
77
What is the facial nerve (CN VII) responsible for?
✓ Answer:
B
Facial expression, taste from anterior 2/3 of tongue, and lacrimation/salivation
The Facial Nerve (CN VII) has multiple functions: Motor = Muscles of facial expression (forehead, eyes, nose, mouth - raises eyebrows, closes eyes, smiles). Sensory = Taste from the anterior 2/3 of tongue (via chorda tympani branch). Parasympathetic = Lacrimation (tear secretion - lacrimal gland) and Salivation (submandibular and sublingual glands). Bell's Palsy: Idiopathic (often viral - HSV) unilateral lower motor neuron facial nerve palsy causing entire face on one side to droop (including forehead - helps distinguish from UMN stroke where forehead spared due to bilateral cortical representation). Treatment: Prednisolone (oral steroids), eye protection. Most recover fully within weeks.
78
What is the difference between sensory and motor nerve fibres?
✓ Answer:
C
Sensory (afferent) fibres carry signals from receptors to the CNS; motor (efferent) fibres carry signals from the CNS to muscles and glands
Sensory (Afferent) fibres: Carry signals FROM sensory receptors (skin, muscle, organs) TO the CNS. Cell bodies in dorsal root ganglia (spinal nerves) or cranial nerve ganglia. Enter the spinal cord via the dorsal root (Bell-Magendie Law - dorsal = sensory). Motor (Efferent) fibres: Carry commands FROM CNS TO effectors (muscles and glands). Cell bodies in anterior horn of spinal cord (somatic motor) or lateral horn (autonomic). Leave via the ventral root (Bell-Magendie Law - ventral = motor). Most spinal nerves are mixed nerves (contain both sensory and motor fibres). Mnemonic: SAME DAVE = Sensory = Afferent; Motor = Efferent; Dorsal = Afferent; Ventral = Efferent.
79
What is an EEG (Electroencephalogram) and what is it used for?
✓ Answer:
B
A test that records the electrical activity of the brain using electrodes placed on the scalp - used to diagnose epilepsy and sleep disorders
An EEG (Electroencephalogram) records electrical activity (brain waves) from multiple electrodes placed on the scalp - non-invasive. Normal brain wave patterns by frequency: Delta (0.5-4 Hz) = Deep sleep, infants, brain disease. Theta (4-8 Hz) = Drowsiness, light sleep, meditation. Alpha (8-13 Hz) = Relaxed, awake, eyes closed. Beta (13-30 Hz) = Alert, active thinking, anxiety. Gamma (>30 Hz) = High-level cognitive processing. Clinical uses: Epilepsy diagnosis (characteristic spike-wave patterns), Sleep disorders (polysomnography), Encephalopathy, Brain death (flat/isoelectric EEG), and Monitoring sedation in ICU. Limitations: Poor spatial resolution (compared to MRI). Advantages: Excellent temporal resolution, cheap, non-invasive, and bedside.
80
What part of the brain is primarily responsible for processing vision?
✓ Answer:
D
Occipital lobe
The Occipital Lobe is located at the posterior pole of the brain and is the primary centre for visual processing. Key areas: Primary Visual Cortex (V1) = Brodmann area 17, located in the calcarine sulcus - receives raw visual input from the thalamus (LGN). Visual association cortex (V2-V5) = Processes colour, motion, depth, shape. Two visual processing streams: Dorsal stream (Where pathway) = Occipital > Parietal - spatial awareness, motion. Ventral stream (What pathway) = Occipital > Temporal - object recognition, face recognition. Occipital lobe damage: Cortical blindness (cannot see but pupils react to light), Visual agnosia (cannot recognise objects). Anton syndrome: Patient is blind but denies it (confabulates).