A radiculopathy is not a specific condition, but rather a description of a problem, in which one or more nerves are affected and do not work properly. The emphasis is on the nerve root. This can result in pain (radicular pain), weakness, numbness, or difficulty controlling specific muscles.
In a radiculopathy, the problem is at or near the root of the nerve, along the spine. However, the pain or other symptoms may manifest in the extremity. For example, a nerve root impingement in the neck can produce pain and weakness in the forearm. Likewise, an impingement in the lower back, or lumbar-sacral spine, can be manifested with symptoms in the foot. Polyradiculopathy refers to the condition where more than one spinal nerve root is affected.
So, your EMG shows evidence that you have several nerve roots which are being affected.
The way you have it listed is a little confusing. Usually the discs between the vertebrae are listed as the C5-6 disc, C6-7 disc, C7-T1 disc, T1-2 disc, etc. Then the nerves roots are called the C5, C6, C7, C8, T1, etc. Since the cervical spine has one more nerve root than vertebral bodies, the root associated with the C7-T1 disc is called the C8 nerve root.
So, you either have problems with the C5, C6, C7, C8 nerve roots, if they are listing all of the affected nerves, or, if it is referring to discs, then the affected nerves would be C6, C7, C8.