1. (B): Orthostatic tremor or “shaky leg syndrome” occurs predominantly in the elderly upon standing causing quivering of the legs and difficulties in walking. It is diagnosed by surface EMG in the lower extremities and paraspinal muscles with the patient standing. The EMG pattern displays high amplitude 14- to 18-Hz tremor bursts, distinctive to this disorder. Exaggerated physiologic tremor is of 12 to 14 Hz frequency, best recorded in finger flexors and extensors. (Daube 2002, p. 404)

2. (A): Surface EMG recording lacks selectivity because of interference from other surrounding muscles. This is minimized by the use of shorter interelectrode distance with superficial muscle recording. The low frequency filter should be at least 30 Hz to minimize movement artifact. Surface EMG has the advantages of being a noninvasive method, with easy accessibility of muscles.

When evaluating deep muscles, intramuscular electrodes should be used. (Daube 2002, pp. 400-402)

3. (B): P300 is the most common event-related potential to be recorded by the oddball technique. It is better seen with averaging and is defined characteristically by a bilateral midparietal distribution with a latency of 300 ms and amplitude of 10 μV. Its clinical significance is still debatable and is likely to represent a complex integration of generators involved in selected attention. Its amplitude is decreased and its latency is prolonged in Alzheimers disease and other neurodegenerative disorders like Parkinsons disease or multiple sclerosis. The clinical significance of P300 potential in comatose patients is still unknown. (Daube 2002, p. 164; Ebersole and Pedley, pp. 431-433)

4. (D): In the sympathetic nervous pathway, most postganglionic neurotransmitters act through norepinephrine on adrenergic receptors. In the case of sweat glands, the sympathetic effect is mediated by acetylcholine through the M3 muscarinic receptors. (Daube 2002, pp. 438-440)

5. (C): In healthy subjects, the heart rate fluctuates with the respiratory cycle. Parasympathetic influence by the vagal nerve is highest by the end of inspiration and early expiration. This effect is minimal during early and middle inspiration. (Daube 2002, p. 441)

6. (B): Upon standing, there is pooling of venous blood to the abdomen and lower extremities. This leads to decreased venous return, mean arterial pressure, and cardiac output by approximately 20%. To maintain postural normotension, a compensatory vasoconstriction of the splanchnic, peripheral, and renal beds is mainly mediated by baroreflexes. (Daube 2002, pp. 442-443)

7. (D): The thermoregulatory sweat testing is typically used to evaluate peripheral neuropathies affecting small-diameter nerve fibers. Several techniques have been used including hot baths, infrared or incandescent lights to produce sweating. However, the most reliable and satisfactory technique is the use of controlled-environment cabinets where temperature is controlled and the whole body is equally heated. (Daube 2002, pp. 458-462)

8. (C): Pancoast tumors are tumors of the pulmonary apex, commonly compressing the sympathetic ganglion chain. The loss of sympathetic outflow causes anhidrosis or loss of sweat in the ipsilateral face, upper trunk, and arms (depending on the extent of compression of the sympathetic chain), in addition to a horner’s syndrome. (Daube 2002, pp. 462-464)

9. (B): Dystonia is defined as an intense, prolonged, and simultaneous involuntary contraction of agonist and antagonist muscles producing painful stiffness across a joint and abnormal posturing. (Daube 2002, p. 409)

10. (A): Rubral tremor, also known as Holmes tremor typically presents with a low frequency intentional or resting tremor of 2- to 4-Hz frequency, occurring months after a midbrain insult. (Daube 2002, pp. 402-405)

11. (B): Heart rate depends on the modulation of sympathetic and parasympathetic systems on the intrinsic firing rate of the sinus node. There is frequent spontaneous autonomic fluctuation of the heart rate. At rest, the parasympathetic tone predominates over the sympathetic tone. Also, the effect of the parasympathetic tone is shorter lived than that of the sympathetic effect. (Daube 2002, p. 441)

12. (C): Tremor of Parkinson’s disease is maximal at rest and attenuates with action. The typical tremor frequency is 4- to 7-Hz with alternating agonist and antagonist contractions. The frequency is usually similar throughout the body, becoming more regular as the disease progresses. (Daube 2002, p. 403)

13. (A): The QSART is abnormal in approximately 80% of patients with small fiber or C-fiber neuropathy. In this patient population, it is the most sensitive noninvasive diagnostic test. (Daube 2002, pp. 445-447)