Validation Study of Neuropathic Pain
Validation Study of Neuropathic Pain
This study seeks to validate clinically evoked or obtained objective pain signs with the
 patient's corresponding quantified subjective pain symptoms. This will allow for validation
 of objective clinical pain signs to then be used to begin to classify patients with pain
 based on symptoms and signs. This then can be used as a basis for further study of
 neuropathic pain mechanisms in human patients.
Inclusion Criteria:

 -  Subjects must be 18 years of age and older, and able to provide informed consent and
 communicate in English. Pain rating inclusion criteria will be pain greater than 3 up
 to 9, as rated on the 0-10 pain scale, where 10 is the worst pain imaginable. This
 rating is based on the numeric pain rating scale (NPRS).

 -  PHN - Subjects with PHN will have a history of pain of at least 6 months duration in
 the area that was the site of a zoster rash resulting in nerve injury. In most cases,
 subjects experience a number of sensory abnormalities in the affected area, ranging
 from pain to numbness, and various degrees of hypersensitivity. Subjects with PHN must
 otherwise be in stable health. Pain rating inclusion criteria for PHN subjects will be
 pain greater than 3 up to 9, as rated on the 0-10 pain scale, where 10 is the worst
 pain imaginable.

 -  PDN - Subjects with diabetes mellitus and neuropathy who have a history of pain,
 predominantly in the lower extremities, of at least 6 months duration qualify for the
 diagnosis of PDN for purposes of this study. In most cases PDN is due to small fiber
 neuropathy, so physical examination should yield sensory abnormalities, such as pain,
 paresthesiae and numbness. Motor function and stretch reflex abnormalities are common
 but not necessary for inclusion. PDN patients in whom large fiber functions are
 affected, experience weakness and decreased or absent stretch reflexes, respectively,
 and are eligible for this study. Other causes of neuropathy will be excluded. PDN
 patients with pain rating of greater than 3 up to 9 on 0-10 scale will be included.

 -  SCI pain - Subjects with SCI and pain of at least 6 months duration will be invited to
 participate. In most cases, these subjects' sensory, motor and stretch reflex
 abnormalities are consistent with SCI. Sensory findings range form complete loss of
 sensation to preservation of all sensory modalities. Motor findings range from mild
 weakness to complete paralysis. Stretch reflexes are most frequently increased though
 in a few patients they can be absent. Based on the constellation of sensory and motor
 findings in particular patients, diagnosis of complete versus incomplete SCI is made.
 In this study we will study patients with incomplete SCI who have pain at level of
 injury or below level of injury, or both. Subjects with SCI who have pain rating of
 greater than 3 up to 9 on 0-10 scale will be included.

 Exclusion Criteria:

 -  Patients with pain due to disorders other than PDN, PTN, or SCI, as well as unknown
 causes, will be excluded.

 -  Patients with neuropathies from causes such as vasculitis, demyelinating
 polyneuropathies, HIV-associated neuropathy, and paraneoplastic and post-infectious
 neuropathies will be excluded.

 -  Patients with chemotherapy-induced neuropathy will be excluded.

 -  Patients who suffer from pain due to different pain mechanisms will be excluded.

 -  Patients with other pain (at a different site) that is more severe than their PDN or
 PTN pain will be excluded.

 -  Patients with a history of recent or ongoing alcohol or other drug addiction disorders
 (as self-reported or previously documented in the medical record) will be excluded.

 -  Patients who are determined to have cognitive and reading impairments which would
 preclude them from completing questionnaires will be excluded.

 -  Patients whose chronic medical and psychiatric comorbidities are not under optimal
 control, or who are currently experiencing an acute exacerbation of a medical or
 psychiatric comorbidity, will be excluded.