Guidelines For Reporting Worker’s Impairment

This is the second in a 2-part series on closing Workers’ Comp cases.


This article is to help physicians measure and record impairments to assure proper disability rating and compensation.

Workers who have been permanently impaired by a work injury are compensated based on the severity of the impairment. The amount of compensation depends upon the extent of the impairment found by the attending physician. The standards are arbitrary rules used to convert physical findings to a disability rating.

One of our better informed readers wrote in response to our statement in the last issue that “only the attending physician may rate an impairment.” The reader stated correctly that attending physicians record impairments and give medical diagnoses, and the actual rating of the disability is done by the Workers’ Compensation Department. We apologize for any confusion this misstatement may have caused.

“Impairment means a permanent loss of use or function of a body part/area or system due to the compensable condition.” The Workers’ Compensation Division (of the Department of Consumer and Business Services) rates the disability for the purposes of a compensation award, based on the attending physician’s reports setting forth the impairment. The doctor, then, reports the impairment. The Workers’ Compensation Division rates the disability based on the impairment findings reported by the attending physician (or the medical arbiter), in order to set the level of compensation for the disability under the workers’ comp law and regulations.

This article takes a condensed look at the “disability rating standards” found in the Oregon Administrative Regulations.

When an injured worker is impaired by a compensable condition that combines with a preexisting condition, the doctor needs to allocate the percentage of the disability related to the compensable (work-injury caused) condition as separate from all other conditions.

For example, a female has a work-related low back strain and she is also pregnant. The doctor needs to apportion the extent to which her range of motion limitations are attributable to the work injury as opposed to the pregnancy.

So, a doctor must always apportion the extent to which any disability is caused by a compensable condition as opposed to all other (non-compensable) conditions.

These are the most common types of impairments:

1. Loss of Range of Motion – measured by degrees of flexion, extension, rotation, etc. Doctors must record the degree of impairment in terms of active, not passive, range of motion.

2. Loss of Sensation – this is based on two point discrimination. The standard considers 6 millimeters apart or less, normal; 7-10 millimeters, less than normal; 11-15 millimeters, protective sensation; and greater than 15 millimeters, total loss of sensation.

3. Loss of Strength – The 0 to 5 international grading system and method noted in the AMA Guides to the Evaluation of Permanent Impairment (3rd Ed. Revised 1990) is listed. 5/15 is normal. Ratings descend, 5-/5, 4+/5, 4/5, 4-/5, etc. At 5/5, the worker retains range of motion against gravity with full resistance applied. At 4/5, the worker retains range of motion against gravity with some resistance applied. At 3/5, …without resistance applied; at 2/5, the worker has to have some assistance. At 1/5, the worker has only slight muscle contractility; and at 0/5, no muscle contractility.

In reporting loss of strength, the nerve which supplies or innervates the muscle must he identified. The disability is based on the nerve. For muscles supplied by the same nerve, the loss of strength is determined by averaging the percentages of impairment for each involved muscle to arrive at a single percentage of impairment for the involved nerve.

4. Amputation – For example, of a finger, the extent of disability depends on whether loss is only of skin, or involves significant flesh, or bone, or extends beyond the distal phalanx to the middle phalanx.

Disabilities are also based on hearing and visual losses; impairments to the abdomen; impairments to the cardiovascular, respiratory and other internal systems; and mental illnesses resulting in impairments.

A worker may he entitled to an award for a chronic condition that limits the repetitive use of a body part.

The rules can be applied only if the doctor provides the degree/extent of impairment and any needed apportionment.

The ultimate percentage of disability and amount of compensation are calculated by Workers’ Compensation Division personnel using objective regulations. But their starting point is the impairment reported by the attending physician.

This article was prepared by Robert F. Webber