Basis of the Electroretinogram An electrical potential exists between the cornea and the fundus of the living eye. When the eye is illuminated by a flash of light a small potential is generated in addition to this corneofundal potential, which forms the ERG. This is analogous to the way in which the ECG is recorded above the steady skin potential. The final response is the sum of a number of co...

PURPOSE Cadaveric palmar dissections reveal an ulnar sensory crossover (Berrettini anastomosis) to the third common palmar nerve so frequently that this crossover is considered a normal part of the anatomy. No literature has documented electrophysiologic evidence of the Berrettini anastomosis (BA). Presentation of third digit ulnar sensory crossover waveforms. METHODS Retrospective chart revi...

Brachial plexus injuries represent a complex clinical challenge from both a diagnostic and treatment standpoint. Given the potential etiologic mechanisms of injury, as well as the varied number of anatomic sites vulnerable to such injury, it is essential that a precise diagnostic approach be utilized. From a neurophysiologic perspective, the electrodiagnostic examination has been shown to be th...

Schwannoma is an encapsulated nerve sheath tumor that is distinct from neurofibromatosis. It is defined as the occurrence of multiple schwannomas without any bilateral vestibular schwannomas. A 46-year-old man with multiple schwannomas involving peripheral nerves of the ipsilateral lower extremity presented with neurologic symptoms. Electrodiagnostic studies revealed multiple mononeuropathies i...

Posterior interosseous nerve entrapment is a potential cause of upper extremity muscle weakness and pain. The diagnosis may be difficult to make clinically, and electrodiagnostic tests may not identify the exact site of nerve compression. We report a case of posterior interosseous nerve entrapment in which electrodiagnostic studies suggested radial neuropathy at the level of the spiral groove, ...

The motor neuron diseases are a set of disorders associated with the selective degeneration of motor neurons. Amyotrophic lateral sclerosis (ALS) is the most common and confers the gravest prognosis. Although ALS occurs with known genetic causes in a small minority, other motor neuron disorders have well-defined genetic mutations. Electrodiagnostic testing is important to distinguish these vari...

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Amyotrophic Lateral Sclerosis (ALS) are two separate disease entities with differing clinical and electrodiagnostic features. We report the case of a 56-year-old female who was referred to us with a confusing clinical and electrodiagnostic picture of CIDP vs ALS. In spite of immunosuppressive treatments, her condition rapidly ...