The Evaluation of Permanent Impairment

The permanent impairment provisions of the Workers Rehabilitation and Compensation Act are covered in sections 70 to 72.

Introduction

Section 71 of the Northern Territory Workers Rehabilitation and Compensation Act provides a mechanism by which workers may receive a lump sum payment for compensable injuries or illness which result in a permanent impairment.

When considering undertaking permanent impairment assessments the Doctor should be able to demonstrate a degree of independence in respect of the person being assessed.

In addition the Doctor should feel confident that their experience training and skills will lead to a balanced assessment.

For the purposes of the definition of "permanent impairment" in Section 70 of the Act, permanent impairment means an impairment or impairments assessed in accordance with the American Medical Association Guides to the Evaluation of Permanent Impairment (4th edition), as being an impairment, or a combination of impairments, of not less than 5% of the whole person.

The AMA Guides are available for perusal at the office of NT WorkSafe in Darwin.

The AMA Guides provide a structured set of medical criteria to establish medical ratings of permanent impairment.

It is important to note that a permanent impairment rating is not the same as a disability rating. Permanent medical impairment is related directly to the health status of the individual, whereas disability can only be determined within the context of the personal, social, or occupational demands that the individual is unable to meet as a result of the impairment.

Procedure

Before medical evaluation is undertaken to determine a rating of permanent impairment, the doctor should review the whole chapter of the AMA Guides which is applicable to the condition, in order to;

• ascertain the methodology involved,
  
  
• the nature of the particular criteria and,
  
  
• determine the extent of the examination necessary to obtain enough clinical information to rate the impairment.

Careful attention should be paid to the definitions listed in the Glossary

Evaluation

• The first step in rating permanent impairment is to make a thorough clinical evaluation with particular attention to reviewing the history of the condition(s). Then a thorough physical examination should be done, supported by appropriate tests and diagnostic procedures.
  
  
• The second step is analysis of the history, clinical and laboratory findings to determine the nature and extent of the loss, loss of use of, or derangement of the affected body parts, systems or functions.
  
  
• The third step is the comparison of results of the analysis with the criteria that are specified in the AMA Guides for the particular body part, system or function.
  
  
• The final step in rating permanent impairment should take into account all relevant considerations in order to reach a "whole person" impairment rating.

When a single permanent impairment is present, the percent of impairment may be read directly from the text, or it can be related to a part of the body or to the "whole person" by referring to the appropriate tables.

When two or more impairments exist, the value of each impairment is determined separately and related to the "whole person" using the combined Values Chart.

The final impairment value, whether the result of single or combined impairments, may be expressed in terms of the nearest 5%.

Once an assessment is made by the Doctor, the award for the impairment will proceed under the provisions of the Act. Therefore, impairment should not be considered "permanent" until maximum rehabilitation has been achieved and until, in the Doctor's best clinical judgement, the impairment is static or well-stabilised.

If apportionment is needed (see the AMA Guide's Glossary), the analysis must consider the nature of the impairment and its possible relationship to each alleged factor and provide an explanation of the medical basis for all conclusions and opinions.

To establish that a factor could have contributed to the impairment, the analysis and explanation should include, in accordance with scientific and epidemiological principles, reference to the minimum exposure and to its timing that would have been necessary for the factor to have contributed to the impairment, and a discussion of the pathophysiology of the particular condition and of pertinent host characteristics.

The Report

The Doctor should provide clear and well reasoned conclusions about medical matters that are supported by complete and accurate data.

The medical evaluation report should include information such as the following.

Medical Evaluation

• Narrative history of condition(s) with specific reference to onset and course of the condition, any available findings on previous investigations. Treatment and responses to treatment.
  
  
• Results of the present clinical evaluation, including any of the following:
  • physical examination findings;
  • laboratory test results;
  • electrocardiogram;
  • radiographic studies;
  • mental status examination and psychological tests; and
  • other special tests or diagnostic procedures.
    
    
• Assessment of current clinical status.

Analysis of Findings

• Explanation of the impact of medical condition(s) on life activities
  
  
• Explanation of the medical basis for any conclusion that the medical condition has, or has not become static or well-stabilised.

Results of Analysis

• Description of specific clinical findings related to each impairment, with reference to how the findings relate to the criteria described.
  
  
• Explanation of each percent of impairment rating, with reference to the applicable criteria.
  
  
• Summary list of all impairment ratings.
  
  
• Whole person rating for each condition then combined whole person rating using the Combined Values Chart when more than one impairment is present.

More Information

More information for workers on the permanent impairment process can be found in Information Bulletin 13.01.10.