23rd August 2024

A 68-year-old gentleman presents with progressive right hand weakness. He reports he is struggling to grasp a pen

A 68-year-old gentleman presents with progressive right hand weakness. He reports he is struggling to grasp a pen and lift a mug of tea. Most recently he has also noticed a right-sided foot drop.

On examination he has reduced power in his right hand with absent reflexes. He is noted to have tongue fasciculations. He has absent reflexes in both his lower limbs with right-sided weakness extending up to his knee.

He has blood tests, which show no abnormality. He has an MRI head and spine, which is normal.

What investigation would be the most helpful in diagnosing his condition?

Select the SINGLE most appropriate option from the list below. Select ONE option only.