A new method of administering the Grooved Pegboard Test: Performance as a function of handedness and sex

Abstract

The purpose of the present study was twofold: first to examine the influences of sex and handedness on manual performance on the Grooved Pegboard Test; and secondly to provide normative data for two versions (Place and Remove tasks) of the Grooved Pegboard Test, as previous work (Bryden & Roy, 1999) had suggested that the Remove task of the Grooved pegboard may provide a purer measure of motor speed of the two hands than the standard administration of the Grooved Pegboard Test. One hundred and fifty-three (47 males and 106 females) participants completed the Grooved Pegboard Test. Individuals performed the standard version of the Grooved Pegboard Test (Place task) and a novel version of the test (Remove task). In the standard version, participants were timed on their speed for placing the pegs, while in the novel version they were timed on their speed for removing the pegs. Results confirmed previously noted hand and sex differences in the Place task of the Grooved Pegboard Test, as well as the lack of effect of handedness on performance (Bornstein, 1985, Ruff and Parker, 1993, Schmidt et al., 2000). Significant performance differences between the hands were also noted for the Remove task. Findings also indicated that the Remove task was sensitive to sex and handedness effects.

Introduction

Motor tasks are considered to be a fundamental part of any comprehensive neuropsychological evaluation, and are often used as indicators of lesion lateralization (Goldstein, 1974). It is typically assumed, for tests of manual speed or strength, that a preferred hand advantage greater than 10% may indicate a brain lesion ipsilateral to the preferred hand. In contrast, it has been assumed that a lower than 10% advantage of the preferred hand may reflect brain damage contralateral to the preferred hand (Boll, 1981, Reitan and Wolfson, 1993). Early recommendations suggested that lateralized brain damage was likely if either non-preferred hand performance exceeded that of the preferred hand, or the preferred hands’ performance was over 20% better than the non-preferred hand (e.g., Golden, 1978). However, more recent research has raised serious concerns with these recommendations (Thompson, Heaton, Matthews, & Grant, 1987). Using such recommendations, Thompson et al. (1987) found that as many as 36% of normal left-handed individuals would be misclassified as having lateralized hemisphere dysfunction on neuropsychological motor tasks. Likewise, approximately 20% of normal right-handed individuals would have been classified as having dominant hemisphere dysfunction on the basis of performance on several motor tasks. To make matters worse, the performance differences between the preferred and non-preferred hand appear to fluctuate with the particular test used (Bornstein, 1986). For example, almost one-third of normal right-handed individuals have a between-hand performance difference exceeding the original recommendations in at least one neuropsychological motor task. Finally, sex appears to influence performance differences on some motor tasks, but not on others (Bornstein, 1986). Clearly, performance abilities on tests of motor speed and strength should be interpreted with extreme caution.

One commonly used test of motor performance is the Grooved Pegboard Test, which is a component of several neuropsychological assessment batteries, including the Wisconsin Neuropsychological Test Battery (Harley et al., 1980, Matthews and Klove, 1964), the Repeatable Cognitive-Perceptual-Motor Battery (Kelland et al., 1992, Lewis and Kupke, 1992), and the expanded Halstead-Reitan Battery (Heaton, Grant, & Matthews, 1992). As the pegs must be rotated into position to be successfully placed, the Grooved Pegboard Test adds a dimension of complexity not found in other motor tasks, such as the Purdue Pegboard Test (Tiffen, 1968), and thus has been found to be a sensitive instrument in detecting general slowing due to medication or disease progression. For example, researchers have used the Grooved Pegboard Test to evaluate cognitive and motor slowing in bipolar disorder (Wilder-Willis et al., 2001), Asperger syndrome (Weimer, Schatz, Lincoln, Ballantyne, & Trauner, 2001), HIV infection (Honn, Para, Whitacre, & Bornstein, 1999), low birth-weight children (Miller, 1999), and diabetes (Deichmann, 1998). The Grooved Pegboard Test has also been used extensively for identifying lateralized impairment (Haaland et al., 1977, Haaland and Delaney, 1981) in such diseases as Parkinson’s disease (Demakis et al., 2002).

Several individual difference variables have been found to influence the performance abilities of the two hands on tests of motor speed. Specifically, influence of age, education, handedness, and sex have been noted. Whether these individual difference variables influence performance on the Grooved Pegboard Test is highly contentious. With respect to age and education level, Thompson et al. (1987) found neither variable was significantly related to intermanual difference scores. However, Heaton et al. (1992) reported that approximately 40% of the variability in scores for the preferred hand and non-preferred hand could be accounted for by age. Likewise, 17% of the variability in the preferred hand performance score and 13% of the variability in the non-preferred hand performance score was explained by education level. Clearly, it is important to take into account an individual’s age and education level when employing the Grooved Pegboard Test in a neuropsychological battery.

While handedness has been found to influence performance on several motor tasks, it appears to not be a particularly important variable affecting performance on the Grooved Pegboard Test. For example, Ruff and Parker (1993), in a sample of 358 individuals, found no effect of handedness on the performance of the preferred and non-preferred hands, nor did handedness interact with any variables examined. More recently, Schmidt, Oliveira, Rocha, and Abreu-Villaca (2000) conducted a comprehensive study of the influences of handedness on performance on the Grooved Pegboard Test. A significant effect of handedness was found only for the first trial of the test, however, after the first trial, there was no significant difference between left and right-handers. These two studies suggest that there is relatively little or no influence of handedness on performance on the Grooved Pegboard Test.

As stated earlier, sex differences in various neuropsychological tests have been noted by several researchers. For instance, Bornstein (1985) presented normative data on several measures from the Halstead-Reitan Neuropsychological Test Battery. In his extensive study, Bornstein found that men and women differed significantly in performance on the Grooved Pegboard Test for both the preferred hand and the non-preferred hand. On average, women were approximately 4 s faster than men. Thompson et al. (1987) compared the performance of the preferred and non-preferred hands in four neuropsychological motor tests, including the Grooved Pegboard Test. It was found that females tended to have larger percent difference scores than males. Likewise, both Bornstein, 1986, Ruff and Parker, 1993 found that women were significantly faster than men on the Grooved Pegboard Test. However, Peters, Servos, and Day (1990) caution that the sex differences noted by several researchers may be due to finger size rather than sex. In their study, Peters et al. (1990) compared males and females on the Purdue Pegboard, which examines manual dexterity in a slightly different way than the Grooved Pegboard Test. They found that when measures of index finger and thumb thickness were used as a covariate, all significant sex differences in performance disappeared. In a later study, Peters and Campagnaro (1996) found that sex differences in a peg-moving task could be eliminated by controlling for finger size by having participants use tweezers instead of their fingers. These results, however, have not been replicated by other researchers (Hall and Kimura, 1995, Nicholson and Kimura, 1996). The conflicting results may be due to the fact that finger size is difficult to measure accurately. Clearly, a variety of factors other than dexterity determine the magnitude and direction of sex differences in motor tasks.

The purpose of the current study was to examine the influences of sex and handedness on the performance on the Grooved Pegboard Test and to provide normative data using both the standard methodology (Place task) and the revised methodology (Remove task) for the Grooved Pegboard Test. The revised methodology requires participants to remove the pegs from the holes as quickly as possible and place them back into the receptacle. Previous work using this methodology (Bryden & Roy, 1999) showed that the Place task took significantly longer to perform than the Remove task. More specifically, it was found that individuals took, on average, 54.9 s (SD = 5.72) to place the pegs, while they took 16.8 s (SD = 2.14) to remove the pegs in the receptacle. It was also found that the preferred hand was significantly faster than the non-preferred hand for both phases of the test. Further analysis revealed that the difference between the hands was much larger in the Place task (preferred hand = 51.5 s, SD = 5.1; non-preferred hand = 58.5 s, SD = 6.38) than in the Remove task (preferred hand = 16.4 s, SD = 2.03; non-preferred hand = 17.2 s, SD = 2.24). The faster speed of completion and the smaller between-hand difference in the Remove task indicates that the Remove task of the Grooved pegboard may not rely as heavily on visual information, and thus may provide a purer measure of motor speed of the two hands than the standard administration of the Grooved Pegboard Test. As such, the Remove task of the Grooved Pegboard Test may be a worthwhile addition to neuropsychological testing. Furthermore, as our previous work was conducted using only right-handed participants, it was decided that a representative sample of left- and right-handers should be compared on the two versions the Grooved Pegboard Test.