Neurology Practice Questions

Q: Ocular bobbing is seen in which type of brain damage?

Pontine damage. **Explanation:** **Ocular bobbing** is a classic clinical sign characterized by a rapid downward jerk of the eyes followed by a slow drift back to the primary position. **Why Pontine Damage is Correct:** Ocular bobbing is a highly specific localizing sign for **acute destructive lesions of the pons**, most commonly a large pontine hemorrhage, infarct, or tumor. The physiological mechanism involves the destruction of the horizontal gaze centers (Paramedian Pontine Reticular Formation - PPRF) in the pons. When horizontal eye movements are abolished, vertical movements (which are mediated by the midbrain) persist but become dysregulated, resulting in the characteristic "bobbing" motion [2]. **Analysis of Incorrect Options:** * **Midbrain damage:** Lesions here typically cause vertical gaze palsies (e.g., Parinaud syndrome) rather than bobbing. In fact, for ocular bobbing to occur, the midbrain must be relatively intact to facilitate the vertical eye movement [2]. * **Medulla damage:** Medullary lesions are associated with different types of nystagmus (like downbeat nystagmus) or Wallenberg syndrome, but not classic ocular bobbing. * **Cerebellum damage:** While large cerebellar masses can cause bobbing, they do so indirectly by compressing the underlying pons [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Ocular Dipping:** Slow downward movement followed by a fast upward flick (the reverse of bobbing); usually seen in **anoxic encephalopathy**. * **Inverse Bobbing (Ocular Tucking):** Fast upward movement followed by a slow downward drift. * **Localization:** If you see "Bobbing," think **Pons**. If you see "Downbeat Nystagmus," think **Craniovertebral junction** (e.g., Arnold-Chiari malformation). * Ocular bobbing is typically seen in **comatose patients** where spontaneous horizontal eye movements are absent.

Q: Which type of aphasia affects the arcuate fasciculus?

Conduction aphasia. **Explanation:** The correct answer is **Conduction Aphasia**. **1. Why Conduction Aphasia is correct:** Conduction aphasia is caused by a lesion in the **arcuate fasciculus**, the white matter tract that connects Wernicke’s area (sensory speech) to Broca’s area (motor speech). Because the connection between understanding and production is severed, the hallmark clinical feature is **severely impaired repetition**. Patients have fluent speech and intact comprehension but cannot repeat phrases spoken to them. **2. Why the other options are incorrect:** * **Global Aphasia:** Results from large lesions affecting both Broca’s and Wernicke’s areas (often due to total MCA territory infarcts). It involves a complete loss of all language functions (fluency, comprehension, and repetition). * **Anomic Aphasia:** Characterized by difficulty in word-finding (naming objects). It is the mildest form of aphasia and lacks a specific localized lesion, though it is often associated with the angular gyrus. * **Broca’s Aphasia:** Caused by a lesion in the posterior part of the inferior frontal gyrus (Brodmann areas 44, 45). It is a non-fluent aphasia where comprehension is preserved, but speech production is effortful and "telegraphic." **3. NEET-PG High-Yield Clinical Pearls:** * **Repetition is the key:** If repetition is **impaired**, the lesion is "perisylvian" (Broca, Wernicke, or Conduction). If repetition is **preserved**, the lesion is "transcortical." * **Paraphasic errors:** Patients with conduction aphasia often demonstrate "phonemic paraphasias" (substituting similar-sounding words) and frequent self-correction attempts (*conduit d'approche*). * **Vascular Supply:** Most aphasias involve the **Left Middle Cerebral Artery (MCA)**. Conduction aphasia specifically involves the division of the MCA supplying the supramarginal gyrus.

Q: Which of the following tests is not useful for the diagnosis of patients with Ocular Myasthenia Gravis?

Spirometry. **Explanation:** The diagnosis of **Ocular Myasthenia Gravis (OMG)** focuses on confirming neuromuscular junction dysfunction localized to the extraocular and levator muscles. **Why Spirometry is the correct answer:** Spirometry is used to assess pulmonary function (forced vital capacity) in patients with **Generalized Myasthenia Gravis** to monitor for respiratory muscle weakness or an impending myasthenic crisis. In purely **Ocular Myasthenia**, the pathology is restricted to the eyes (ptosis and diplopia); therefore, spirometry provides no diagnostic value for the ocular subtype. **Analysis of other options:** * **MRI Brain:** While not a test for Myasthenia itself, it is **essential for the differential diagnosis** of OMG. It helps rule out compressive lesions (like third nerve palsy or brainstem tumors) that mimic ocular symptoms. * **Anti-MuSK Antibody Titer:** This is a specific serological test. While more common in generalized MG, a subset of seronegative (AChR-negative) patients may test positive for MuSK antibodies. * **Ice Pack Test:** A highly sensitive bedside test for OMG. Cooling the eyelid inhibits acetylcholinesterase, increasing acetylcholine availability and temporarily improving ptosis. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Single Fiber EMG (SFEMG) is the most sensitive test. * **Most Specific Serology:** Anti-AChR antibodies (though often negative in 50% of OMG cases). * **Simpson’s Test:** Sustained upward gaze leading to worsening ptosis (fatigability). * **Cogan’s Lid Twitch:** Brief overshoot of the upper lid when shifting from downgaze to primary position. * **Associated Condition:** Always screen for **Thymoma** using a CT Chest in newly diagnosed MG patients.

Q: A pinpoint pupil is a clinical sign that can indicate which of the following conditions?

Pontine hemorrhage. **Explanation:** **1. Why Pontine Hemorrhage is Correct:** Pinpoint pupils (miosis) are a classic hallmark of **pontine lesions**, specifically pontine hemorrhage. This occurs because the descending sympathetic fibers (which mediate pupillary dilation) pass through the pons. A lesion here disrupts these sympathetic pathways while leaving the parasympathetic supply (via the Oculomotor nerve) intact or unopposed. This results in extreme pupillary constriction. These are often referred to as "bilateral pinpoint pupils" and are typically associated with coma, quadriplegia, and hyperpyrexia. **2. Why the Other Options are Incorrect:** * **Barbiturate Poisoning:** While many sedative-hypnotics cause miosis, barbiturates typically cause mid-range or dilated pupils in severe toxicity due to hypoxia. **Opioid overdose** is the classic toxicological cause of pinpoint pupils, not barbiturates. * **Glaucoma:** Acute angle-closure glaucoma typically presents with a **mid-dilated, vertically oval, and fixed pupil**, accompanied by severe pain and a "stony hard" eyeball. * **Congenital Cataract:** This presents as a **leukocoria** (white pupillary reflex) rather than a change in pupil size. **3. NEET-PG High-Yield Clinical Pearls:** * **Mnemonic for Pinpoint Pupils:** "P's" – **P**ons, **P**hosphates (Organophosphates), **P**ilocarpine, and **P**oppies (Opioids). * **Horner’s Syndrome:** Also causes miosis, but it is unilateral and associated with ptosis and anhidrosis [1]. * **Argyll Robertson Pupil:** Small, irregular pupils that accommodate but do not react to light ("Prostitute’s Pupil"), seen in neurosyphilis. * **Midbrain Lesions:** Usually result in mid-position, fixed pupils.

Q: A 20-year-old man complains of increasing difficulty in hearing over the past several years. Physical examination confirms bilateral sensorineural hearing deficits. MRI discloses bilateral cerebellopontine angle tumors, consistent with schwannomas. This patient has a strong family history for benign tumors, including low-grade gliomas and meningiomas on his mother's side of the family. Which of the following is the probable diagnosis?

Neurofibromatosis type 2. ### Explanation **Correct Answer: B. Neurofibromatosis type 2 (NF2)** The hallmark of **Neurofibromatosis type 2** is the presence of **bilateral vestibular schwannomas** (acoustic neuromas), which typically present in the second or third decade of life with progressive sensorineural hearing loss, tinnitus, or imbalance. NF2 is an autosomal dominant condition caused by a mutation in the *merlin* gene on **chromosome 22**. The clinical triad of NF2 includes bilateral schwannomas, **meningiomas**, and **gliomas** (specifically ependymomas), all of which are mentioned in the patient’s clinical presentation and family history. [1] **Why other options are incorrect:** * **Neurofibromatosis type 1 (NF1):** Associated with the *neurofibromin* gene on **chromosome 17**. It presents with Cafe-au-lait spots, Lisch nodules, optic gliomas, and peripheral neurofibromas, but *not* bilateral vestibular schwannomas. * **Sturge-Weber Syndrome:** A neurocutaneous syndrome characterized by a facial **Port-wine stain** (nevus flammeus), leptomeningeal angiomas, and glaucoma. It does not involve schwannomas. * **Tuberous Sclerosis:** Characterized by the triad of seizures, mental retardation, and adenoma sebaceum. Key findings include **cortical tubers**, subependymal giant cell astrocytomas (SEGA), and renal angiomyolipomas. **Clinical Pearls for NEET-PG:** * **Mnemonic for NF2:** "22" — Chromosome **22**, **2** ears (bilateral schwannomas), and **2** eyes (juvenile posterior subcapsular lenticular opacities/cataracts). * **MISME Syndrome:** NF2 is often remembered by the acronym **M**ultiple **I**nherited **S**chwannomas, **M**eningiomas, and **E**pendymomas. * **Imaging:** MRI with gadolinium is the gold standard for diagnosing cerebellopontine (CP) angle tumors. [1]

Question 1

Ocular bobbing is seen in which type of brain damage?

Accepted Answer

Pontine damage

Answer

Midbrain damage

Answer

Medulla damage

Answer

Cerebellum damage

Question 2

Diagnosis of Myasthenia gravis is typically done by using which of the following tests?

Accepted Answer

Edrophonium test

Answer

Neostigmine test

Answer

Succinylcholine administration

Answer

Atropine challenge

Question 3

Arrange the following drugs in sequence of their use in status epilepticus: Phenytoin, Lorazepam, Phenobarbital, Propofol?

Accepted Answer

Lorazepam > Phenytoin > Phenobarbital > Propofol

Answer

Phenytoin > Lorazepam > Phenobarbital > Propofol

Answer

Lorazepam > Phenobarbital > Propofol > Phenytoin

Answer

Phenobarbital > Phenytoin > Propofol > Lorazepam

Question 4

Which type of aphasia affects the arcuate fasciculus?

Accepted Answer

Conduction aphasia

Answer

Global aphasia

Answer

Anomic aphasia

Answer

Broca's aphasia

Question 5

Palinopsia is seen in occlusion of:

Accepted Answer

P2 Posterior cerebral artery

Answer

M1 Middle cerebral artery

Answer

M2 Middle cerebral artery

Answer

P1 Posterior cerebral artery

Question 6

Which of the following tests is not useful for the diagnosis of patients with Ocular Myasthenia Gravis?

Accepted Answer

Spirometry

Answer

MRI Brain

Answer

Anti MUSK antibody titer

Answer

Ice pack test

Question 7

A pinpoint pupil is a clinical sign that can indicate which of the following conditions?

Accepted Answer

Pontine hemorrhage

Answer

Barbiturate poisoning

Answer

Glaucoma

Answer

Congenital cataract

Question 8

A 20-year-old man complains of increasing difficulty in hearing over the past several years. Physical examination confirms bilateral sensorineural hearing deficits. MRI discloses bilateral cerebellopontine angle tumors, consistent with schwannomas. This patient has a strong family history for benign tumors, including low-grade gliomas and meningiomas on his mother's side of the family. Which of the following is the probable diagnosis?

Accepted Answer

Neurofibromatosis type 2

Answer

Neurofibromatosis type 1

Answer

Sturge-Weber syndrome

Answer

Tuberous sclerosis

Question 9

Dissociative sensory loss is not seen in which of the following conditions?

Accepted Answer

Cauda equina syndrome

Answer

Syringomyelia

Answer

Diabetes mellitus

Answer

Damage to the spinothalamic pathway

Question 10

A patient presents with ataxia, urinary incontinence, and dementia. What is the likely diagnosis?

Accepted Answer

Normal Pressure Hydrocephalus

Answer

Alzheimer's Disease

Answer

Parkinson's disease

Answer

Steel Richardson syndrome

Neurology — MCQs

Neurology — MCQs

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