Validation Study of Neuropathic Pain

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.