Cannabidiol for the Treatment of Diabetic Peripheral Neuropathy: Pilot Study

DPN Pain Level

Pain level will be assessed using the slightly modified "PainDETECT" Questionnaire. This instrument rates subjective pain 0 - 10 (zero no pain, 10 the worst) for current, average and worst over the last 4 weeks. It additionally scores neuropathic symptoms on a scale of zero to 35, with zero being no symptoms to 35 being the worst.

Diabetic peripheral neuropathy diagnosis

DPN severity will be assessed using the DN4 Assessment Tool (including a clinical assessment of hypoesthesia and allodynia). The DN4 tool consists of 10 items across four sections, including both patient interview questions and a physical examination. Each "yes" answer receives 1 point, and each "no" answer receives 0 points. The points from all 10 items are summed to get a total score ranging from a minimum of 0 to a maximum of 10. A total score of 4 or more (≥4) suggests the presence of neuropathic pain. A score of 3 or below indicates that neuropathic pain is unlikely. A higher score is associated with worse DPN.

Diabetic Neuropathy Severity

The DPNCheck™ instrument will be used to assess sural nerve conduction velocity (NCV) and sensory nerve action potential (SNAP) amplitude. Amplitude, The typical normal ranges are \> 40 m/s for SNAV and \> 4 µV SNAP, though values vary by study; lower values indicate worse neuropathy severity, with thresholds like \\(\<40\\) m/s for SNCV and \\(\<5\\) µV (or even \\(\<4\\) µV) for SNAP signaling mild-to-moderate damage, while amplitudes below 1.5 µV may register as zero due to device limits. Device Limitation: Values below 1.5 µV may be registered as 0 µV. Mild DPN: May show delayed SNCV (\< 40 m/s) or low amplitude. Moderate DPN: Often characterized by reduced SNAP amplitude (e.g., \< 5 µV). Severe DPN: Significant decreases in both amplitude and velocity, with very low or undetectable signals

Sleep Quality

Assessment of changes in sleep quality using the sleep scale from the "Medical Outcomes Study" (MOS). The instrument includes 10 Likert-type responses (1 - 6 scale) and are mostly reverse-scoring items (marked with 'R') to transform them into a 0-100 scale. Higher scores generally mean better sleep for "get enough sleep to feel rested" but higher scores indicate more problems for indices like Sleep Disturbance, with specific items like Sleep Quantity measured in hours. Final scores are often expressed as T-scores (mean 50, SD 10) for general population comparison. In the final score higher scores = better sleep

Mood and Depression

Assessment of changes in mood and depression using the Hospital Anxiety and Depression Scale (HADS) instrument.There are 14 Items and the scale has two sub-scales: Anxiety (A) and Depression (D). Each item is rated 0 (not at all) to 3 (definitely/very much). Scoring ranges from 0-7: Normal, 8-10: Borderline, abnormal/Mild, 11-14: Moderate, and 15-21: Severe. There are separate m measures for anxiety and depression. Thus, a higher score is worse.

Quality of Life Index

Assessment of changes in quality of life (using the EQ-5D-5L Quality of Life Scale). The EQ-5D-5L asks about five health dimensions (mobility, self-care, activities, pain/discomfort, anxiety/depression), each with 5 levels (1=no problems, 5=extreme). This is converted into a single "utility" score (0 to 1, with negative values possible) Higher scores are worse while score of 1 is having no problems in that dimension. The measure also includes a separate 0-100 Visual Analogue Scale (EQ-VAS) for self-rated health, with zero as the worst possible health imagined and 100 the best.

Patient Compliance

Assessed by measuring the remaining oil volume in the vials and scoring the completeness of the questionnaires. The higher the volume deviates from the prescribed use, the worse the compliance. The lower the percentage of questionnaires fully completed, the lower the compliance.