WILSON, J.

The employee appeals from a decision denying his claim for permanent and total incapacity benefits under § 34A and, in the alternative, continuing partial incapacity benefits under § 35, by application of § 35B (Decision II). We vacate the administrative judge's denial of the employee's claim for § 34A permanent and total incapacity benefits and recommit the case for further findings. The employee's alternative § 35 request has its genesis in the increase in maximum benefits for partial incapacity granted by the 1986 amendment to § 35. As the employee's injury occurred in 1985, and he had an undisputed "subsequent injury" pursuant to § 35B in 1988, the employee asserts that he is entitled to § 35 benefits at the greater, duration based statutory maximum "rate" of 600 weeks available in 1988, rather than the quantitative statutory maximum of 250 times the maximum weekly compensation rate in effect at the time of the original injury. We agree, reverse that part of the judge's decision that denies the employee § 35 benefits, and remand this case for further findings consistent with this opinion.

The employee was injured at work on February 12, 1985, when he felt a sharp pain in his neck while lifting. He alleges he was incapacitated and out of work for a short time, received workers' compensation, returned to work, and worked for the next three years with pain (Employee's brief, 1-2). In late 1988, the employee consulted with a neurosurgeon, Dr. Peter Goldman, who performed surgery on the employee in November 1988. The employee was paid § 34 benefits for temporary, total incapacity, and has not returned to work since that time (Decision II, 2, filed June 20, 1994; Decision I, Exhibit 4, 2-3, filed March 15, 1993). The employee's weekly compensation rate was paid based on his $546.65 average weekly wage at the time of the 1988 onset of incapacity (Tr. 8-9; Dec. II, 1).

Three and a half months after the operation, Dr. Goldman cleared the employee for light duty work, and the employee contacted the employer about arranging this. He was told by his employer that the company doctor would have to clear him first, and that due to illness, the doctor would be unavailable for six weeks. Days later the employee was beset by the first of what became a series of panic attacks. The employee asserted that the mental problems that were at the root of these panic attacks were causally related to his 1985 industrial injury, and claimed benefits under §§ 13 and 30 for his psychiatric treatment. This claim was the subject of a hearing on December 4, 1992 that resulted in the administrative judge's finding such causal relationship and ordering the medical benefits sought (Dec. I, 3-8).

The employee exhausted the benefits that were available to him under G.L.c. 152, § 34 as amended by St. 1981, c. 572, § 1, which, at the time of the 1985 injury, were limited to an aggregate statutory maximum of 250 times the state average weekly wage. No further benefits were available under § 35 pursuant to the 1981 amendment. See footnote 3, supra. The employee then filed the instant claim for further weekly compensation benefits based on either 1) permanent and total incapacity under § 34A or 2) partial incapacity benefits under the 1986 version of § 35, as amended by St. 1985, c. 572, § 44, and effective at the time of the 1988 onset of incapacity, by application of § 35B. See footnotes 2 and 3, supra. The administrative judge ordered payment of § 34A benefits at conference, and the insurer appealed to a hearing de novo (Dec. II, 1-2).

At hearing on January 21, 1994, the employee and his brother testified, and the following exhibits were marked and entered without objection: 1. "Employee's Biography Sheet;" 2. "Insurer's Defense Sheet;" 3. "Impartial Physician's Exam;" and 4. "Previous Decision." (Dec. II, 1; Tr. 3-4, 8). The parties stipulated to the employee's average weekly wage of $546.65 at the time of his 1988 incapacity, which the insurer acknowledged as the basis for the employee's § 34 weekly compensation rate while those benefits were paid (Tr. 8-9).

The impartial psychiatric examination had been conducted by Dr. Kenneth Jaffe on November 18, 1993 and Dr. Jaffe testified by way of deposition (Dec. II, 1). The administrative judge relied on Dr. Jaffe's report and deposition testimony to deny the employee's claim for § 34A benefits, finding that the employee was at most partially disabled, primarily by his inability to drive more than a few miles from home (Dec. II, 3-4). It was Dr. Jaffe's opinion that the employee "'ought to be able to get back into full-time employment,'" beginning the re-entry into the job market slowly, perhaps with a volunteer position at first, almost immediately (Dec. II, 3-4) (quoting Dep. Tr. at 43). The judge denied the employee's motion to declare the report inadequate or the medical issue complex (Tr. 39). The report, together with the consistent deposition, is prima facie evidence of the medical issues in the case. G.L.c. 152, § 11A(2). The judge additionally appears to have made reference to his initial findings as to the employee's age, education and work experience contained in his earlier March 15, 1993 decision, entered into evidence in this case as Exhibit 4 (Dec. I, 2; Dec. II, 6).

The issue of whether an injury has resulted in permanent and total incapacity is a question of fact for the administrative judge. SeeGramolini's Case, 328 Mass. 86, 88 (1951). We cannot say that the administrative judge erred in his assessment of the medical effect of the employee's panic attack response to his neck injury in view of the definition of the word "permanent" set forth in Yoffa v. Metropolitan Life Insurance Co., 304 Mass. 110, 111 (1939). The court explained that "if recovery is reasonably certain after a fairly definite time," physical disability is not permanent because "[t]he word 'permanent' is the opposite of temporary or transient." Id. at 111; see also, L. Locke, Workmen's Compensation § 344 at 405 (1981); Himmelman v. A.R. Green Sons, 9 Mass. Workers' Comp. Rep. ___ (March 20, 1995). The decision, however, stops short of a complete analysis of both medical and vocational factors that must be considered in order to determine earning capacity. See Scheffler's Case, 419 Mass. 251, 256 (1994); Frennier's Case, 318 Mass. 635, 639 (1945). We therefore vacate the judge's denial of the employee's claim for § 34A total and permanent incapacity benefits and recommit the case for further findings in accordance with Scheffler's Case, supra, and Frennier's Case, supra.

Turning to the issue of entitlement to benefits pursuant to the duration-based aggregate maximum of 600 weeks under the amended § 35, by application of § 35B, the judge relied on Russo v. General Electric Co., 8 Mass. Workers' Comp. Rep. 41 (1994) and Arbogast v. McCord-Winn, Inc., 5 Mass. Workers' Comp. Rep. 189, 196 (1991), and determined that since the employee had not received weekly incapacity benefits at the time of the original 1985 injury, he was not unemployed because of a compensable personal injury and could not have returned to work for a period of not less than two months. "'On that basis alone, application of Section 35B [would be] in error.'" (Dec. II, 6) (quoting Arbogast v. McCord-Winn, Inc., 5 Mass. Workers' Comp. Rep. 189, 196 (1991)). Since the employee had exhausted his §§ 34 and 35 benefits under the aggregate maximum allowed by the pre-1986 Act and the judge found § 35B inapplicable, he ordered only that benefits should continue under §§ 13 and 30.

The employee, upon receipt of the latest decision, immediately filed a Motion for Reconsideration. In that motion, he brought to the attention of the judge proof of the employee's receipt of weekly compensation benefits for approximately four weeks after the 1985 injury. The judge denied the motion in a letter dated November 22, 1994, in which he stated, "Section 35B affects only the rate at which compensation is paid, not the substantive amount the employee is entitled to."

As an initial matter, we dispose of the insurer's argument that § 35B should not apply to this claim because of the employee's failure to prove that he lost time from work and received weekly compensation benefits at the time of his original injury in 1985 (Insurer's brief, 10). We agree that the employee had to prove this initial incapacity as part of his § 35B claim, see Russo v. General Electric, 8 Mass. Workers' Comp. Rep. 41 (1994), and that the employee failed to introduce evidence to that effect. Nonetheless, we note that the insurer accepted the claim for § 34 benefits when the employee subsequently left work in 1988, and paid those benefits at a weekly compensation rate based on the employee's average weekly wage at that time, not on the employee's average weekly wage at the time of his original injury (Tr. 8-9). Indeed, the insurer stipulated to that $546.65 average weekly wage at the hearing (Dec. II, 1). There is only one 1985 industrial accident in this matter, and the causal connection between the onset of the employee's psychological injury and that original incident is law of the case (Dec. II, 2; Dec. I, 7). Therefore, the only explanation for the insurer's acceptance of and stipulation to the 1988 average weekly wage as the basis for calculating the employee's weekly compensation rate is that it has constructively accepted and stipulated to the application of § 35B to this case. The 1989 psychological incapacity was a continuation of the period of incapacity that commenced with the 1988 surgery and recuperation. That entire period of incapacity is attributable to the change in medical condition leading to that surgery — a "subsequent injury" within the meaning of § 35B. The insurer thus has waived any hindsight objections it may have in this regard.

The question we next address is to what extent does § 35B apply? There is agreement that, upon satisfaction of the factual predicate, the employee claiming the benefit of § 35B is to be paid compensation "at the rate in effect at the time of the subsequent injury." The term, "rate," however, is ambiguous. We therefore look to the legislative history of that section to aid in our understanding of what meaning the term was intended to convey.

We begin with some historical context. In 1968, just two years before the enactment of § 35B in St. 1970, c. 667, § 1, Laurence Locke wrote a critique of the then current system of periodic legislative revision of the benefit scale under the Act.

The original Workmen's Compensation Act provided weekly total incapacity benefits of one half the average weekly wage, but not more than ten dollars nor less than four dollars a week; the period of compensation was limited to five hundred weeks and the total amount to three thousand dollars. Over the years, as working people have achieved a higher standard of living and the value of the dollar has declined, the legislature has revised the benefit scale, increasing the rate of compensation, the weekly maximums and minimums, eliminating the limitation as to number of weeks during which compensation is payable, and raising the aggregate maximum payable for total and partial incapacity compensation. . . .

The rate of compensation is determined by the statute in force at the time of injury; injured workmen do not get the benefit of later increases in the rate of compensation.

. . . .

The present system of compensation benefits has been criticized on several grounds: (1) Inadequacy,. . . . To limit payment during total incapacity to $58 or even $65 weekly [the weekly maximum as of 10/13/68] for an employee earning $8,000 to $15,000 a year renders compensation ineffective to replace his wage loss from employment-related disability. . . . (2) Obsolescence, particularly for employees whose injuries occurred before the current legislative amendments and who are restricted to the lower benefit scale. (3) Political controversy. A system requiring repeated legislative amendment of the benefit scale makes compensation benefits a "political football."

L. Locke, Workmen's Compensation § 302 (1968) (emphasis added).

The "rates" that Locke addressed were those established in the "benefits scales" — the legislatively set weekly minimums and maximums, and the statutory maximums, i.e. the total amounts that employees could receive under §§ 34 and 35, separately or in an aggregate amount, depending on which statute was in effect at any given time. Then, after § 35B was enacted, Locke wrote in the supplemental pocket part, and later in his Workmen's Compensation (2d ed. 1981):

In a further effort to overcome the obsolescence of the benefit scale, the legislature in 1970 provided that an 'employee who has been receiving compensation . . . and who has returned to work for a period of not less than two months shall, if he is subsequently injured and receives compensation, be paid such compensation at the rate in effect at the time of the subsequent injury whether or not such subsequent injury is determined to be a recurrence of the former injury. . . .' On a common-sense construction of the section, it requires that compensation be paid at the current benefit scale when a workman suffers a subsequent period of incapacity after working for at least two months following an earlier for which he was paid compensation. Before this section, benefits would be paid at the current rate only if the later period of incapacity were deemed a new injury. . . .

Id. at § 302 (emphasis added).

Locke's focus continued to be on the matter of the "rates" as set by the legislature in its adjustments of the "benefit scale." It seems clear that his interpretation of the effect of § 35B was that employees receive the higher weekly and statutory maximums that obtained at the time of the "subsequent injury," in order to counteract the erosion of benefits through obsolescence.

Our reading of the scant, but probative legislative history to § 35B indicates that the legislature did indeed mean what Locke thought it did. The text of the section was originally introduced in 1970 House Doc. No. 5589, which bill contained two sections. Section 1 was the exact language that found its way into the body of § 35B. See footnote 1 supra. Section 2 addressed only the effective date of the statute and was amended out of the bill when 1970 House Doc. No. 5589 was superseded by its only later version, 1970 House Doc. No. 5930. Section 2 of that enacted version of § 35B, stated: "This act shall take effect February 1, 1971." However, the earlier version of that section, embodied in 1970 House Doc. No. 5589, included the following language:

This act shall take effect when the new rates are set for workmen's compensation insurance (emphasis added).

The inclusion of this language is highly probative of the Legislature's intent with regard to its use of the term, "rate," just six lines earlier in the same statute.

"Rates" contemplated by "the new rates . . . set for workmen's compensation insurance" must be understood as those involved in the periodic legislative revision of the benefit scale. The most regularly revised benefit scale prior to the enactment of § 35B had been the weekly maximums and minimums under §§ 34, 34A and 35. These had increased, on average, every other year from the end of World War II until November 23, 1969, the date of the last pre-§ 35B increase. See L. Locke, Workmen's Compensation § 302 (2d ed. 1981), the tables of benefit scale adjustments in particular. Moreover, the statutory maximums under §§ 34 and 35, although unchanged from 1961 until 1968, were beginning to creep upwards as of 1969, and went into a period of yearly escalation as of November 1, 1971. See id. The compelling inference to be drawn from this information is that in enacting § 35B, the Legislature was concerned with keeping employees current with these "rates" in the event of a subsequent injury relating back to an old injury. Indeed, the drafters tied the effective date for the new entitlement under the proposed statute in a neat little package to the next "rate" increases for workers' compensation insurance that were contemplated. That the Legislature ultimately saw fit to institute the new statute without this nexus to the rate increases — wholly unnecessary as it was — does not dim the light that this initial version sheds on the Legislature's intent regarding its use of the term, "rate," therein.

The use of unenacted, proposed legislation as a tool in the aid of statutory construction is wholly sanctioned by the courts of the Commonwealth. In some cases, it is appropriate to read the elimination of a clause or section as probative of the Legislature's intent to exclude the subject matter therein from the scope of the statute. See Miller's Case, 244 Mass. 281, 285 (1923) (court refused to read "legally bound to support" as inclusive of civil liability, where element of civil liability had been proposed, and then expressly eliminated from statute prior to enactment). In other cases, proposed amendments to statutes are defeated, and the court draws inferences from the attempts. See Pereira v. New England LNG Co., Inc., 364 Mass. 109, 122 (1973) (two attempts to insert language requiring municipal approval for gas storage facility indicative of legislative intent that such approval was not required in unamended statutes). Even more broadly, the Court in American Mutual Liability Insurance Co. v. Commonwealth, 379 Mass. 398 (1979), used the background of a decade of defeated legislation attempting to expand the function of the Second Injury Fund as a clear policy undergirding its holding that the amendment of § 37 finally enacted in 1973 should be applied retroactively. See id. at 403-405 and n. 11 (court took judicial notice of legislative history, which showed attempts "almost every year" to enact the more expansive version of § 37). See generally, L. Locke, Workmen's Compensation § 30 (2d ed. 1981). In the instant case, we likewise take judicial notice of the history of § 35B prior to its enactment. The elimination of the language tying the effective date of § 35B to the Legislature's establishment of new workers' compensation rates is analogous to the history of attempted amendments relied upon in Pereira and American Mutual: it lends context to the concerns of the Legislature as embodied in the statute's final enactment. We conclude that the employee's rate of compensation pursuant to § 35B includes the meaning of "rate" used in the draft phrase, "when the new rates are set for workmen's compensation insurance." In our view, moreover, the meaning of "rate" is inextricably bound to legislative adjustments of both weekly maximum benefit scales and cumulative maximum benefits, whether calculated by quantity of money or duration of total weeks. This being so, the judge erred when he concluded that "Section 35B affects only the rate at which compensation is paid, not the substantive, aggregate amount the employee is entitled to." See footnote 6, supra. The employee prevails with regard to his contention that he is entitled to the 600 week statutory maximum rate for § 35 benefits as of the time of his subsequent injury and incapacity in 1988, which commenced with his surgery, and is claimed to continue as a causally related psychological injury claim.

Our interpretation of the legislative history to § 35B is confirmed by the decision of the Appeals Court in Bernardo's Case, 24 Mass. App. Ct. 48 (1987). Just as in the instant case, the Appeals Court was presented with the issue of whether § 35B was intended to benefit a "subsequently injured" employee by allowing him to receive the larger aggregate amount of statutory maximum benefits available at the time of the later change in the employee's condition. Id. at 49, 51. The Appeals Court affirmed the Superior Court order allowing the employee to collect weekly benefits up to the aggregate statutory maximum in effect at the time of the subsequent injury. Id. at 50-52.

As a final matter, the insurer argues that payment of § 35 benefits in accordance with the statutory maximum rate in effect as of the subsequent injury in 1988 entails a reassignment of the injury date for the employee's psychological injury (Insurer's brief, 9). It is law of the case that the psychological injury is causally related to the original 1985 injury (Dec. I, 7). That liability finding, however, is irrelevant to the application of a new rate of compensation under § 35B. As stated in Don Francisco's Case, 14 Mass. App. Ct. 456, 463 (1982), "[u]nder § 35B . . . the employee's right to compensation at the increased rate and the insurer's burden to pay it originate in the change in the employee's condition subsequent to his return to work." Id. at 463. The onset of the employee's psychological injury is a component of the subsequent "change in the employee's condition," occurring, as it did, as a result of the employee's surgery and related diminished work capacity (Dec. I, 2-5). The psychological condition is not a new, unrelated injury that would remove it from the reach of § 35B altogether. Our conclusion that the new statutory maximum rate applies to it does not retroactively transform the nature of liability already determined in this matter.

We reverse the judge's denial of the employee's application for § 35 benefits, and remand the case for further findings regarding the extent of the employee's incapacity under § 34A or § 35. We affirm the balance of the decision.

So ordered.

_________________________ Sara Holmes Wilson Administrative Law Judge

_________________________ Carolynn N. Fischel Administrative Law Judge

__________________________ William A. McCarthy Administrative Law Judge

Filed: November 21, 1995