identify the likely source of the motor deficits described below. Consider both the sensory and the motor components of the pyramidal system which may be involved. Explain how you reached your conclusion including how you distinguished this particular deficit from the other possibilities.
1. A patient with normal strength displays a waddling gait and maintains a wide stance in order to stay upright. When seated quietly the patient’s muscles are quiet. The patient has great difficulty when asked to touch an index finger to the nose. A Romberg test could not be performed as the patient was unable to balance reliably with feet together even with eyes open.
2. A patient with normal strength displays a resting tremor in the left arm. The tremor diminishes when the arm is in motion (such as when the patient is reaching for something, or when the patient is asked to touch finger to nose). [note: in the real world the character of the tremor and its rate would be important. For our purposes, however, we have only considered one source of resting tremor]
3. A patient with normal strength complains of unusual clumsiness lately. The patient displays a positive sign during the Romberg test (sways with eyes closed). With the patient lying down, a physician moves the big toe up and down. The patient is asked to identify dorsiflexion and plantarflexion of the toe without looking. The patient responds “What’s dorsiflexion?” Subsequently the patient is asked if the big toe is up or down. The patient is unable to correctly identify the position of the toe.
4. Another patient with normal strength complains of dizziness. Blood pressure (sitting and standing), blood hemoglobin levels, and blood oxygen levels are all determined to be normal. The patient displays a positive sign during the Romberg test (sways with eyes closed). Unlike the patient above, this patient has no difficulty sensing the position of limbs and digits in space. When asked to describe the feelings of dizziness, the patient explains that it feels like he has been spinning on a carnival ride.
5. A blind patient reports being unable to maintain balance adequately enough to walk across a room. The patient has no history of motor deficits, but is currently being treated for a serious ear infection. While the infection is responding to treatment, there is still considerable inflammation. The patient is reassured that once the ear infection subsides, balance should also return to normal.
6. What is the source of the above blind patient’s balance problems, and how is the patient’s blindness relevant to the recently developed motor problems?