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Table 17.21 Characteristics of the Galveston Orientation and Amnesia Test

 
Criterion Evidence
Reliability

Interobserver Reliability: Kendall tau=0.99 (p<0.001) and 0.99 for individual items (Levin et al., 1979).

Internal Consistency: On Rasch analysis, person separation reliability=2.46 and item separation reliability=8.68, and all items adhered to a single construct (Bode et al., 2000).

Validity

Construct Validity: On Rasch analysis, the constructed item hierarchy confirmed previous research, namely that focus should be on the person, that place and time precedes dealing with memories surrounding the injury (Bode et al., 2000). GOAT scores correlated positively with Glasgow Coma Scale (GCS) scores (r=0.456, p<0.002) and with admission and discharge FIM scores (r=0.701 and 0.531, respectively) (Novack et al., 2000). Levin et al. (1979) reported impaired eye opening on the GCS was strongly related to regaining orientation as measured on the GOAT(χ2=21.09; p<0.00001), GCS motor responding and subsequent GOAT performance (χ2=18.98; p<0.00001) and GCS verbal responding and persistence of amnesia as assessed by GOAT (χ2=19.53; p<0.00001). Levin et al. (1979) also demonstrated that GOAT performance was associated with CT findings (p=0.02).

Concurrent Validity: Scores on GOAT and JFC PTA scale are reported to be strongly correlated (r=0.99; p<0.000) (Forrester et al., 1994) and GOAT scores were also correlated with Orientation Log scores (r=0.901, p<0.001) (Novack et al., 2000). GOAT assessment of PTA correlated with Length of coma (r2=0.575, p<0.0001), however, this relationship varied with severity of injury and duration of coma (Katz & Alexander, 1994).

Predictive Validity: PTA, measured by GOAT scores, is a significant independent predictor of functional outcome (p=0.00005) as assessed by DRS and FIM total, motor, and cognitive scores (Zafonte et al., 1997). Length of PTA as assessed by GOAT was significantly associated with employment status at 1 year post-injury (Cifu et al., 1997) (TBI). Levin et al. (1979) reported GOAT performance association with long term outcome (at least 6 months post-injury) rated on the GOS (p<0.0001). Katz and Alexander (1994)(TBI) reported GOAT scores (PTA) to be associated with GOS at 6 and 12 months post injury (r2=0.447 and 0.476, respectively, p<0.0001) among patients with diffuse axonal injury.

Responsiveness N/A
Tested for ABI/ TBI patients? Designed for use with TBI patients
Other Formats A-GOAT: Developed specifically for use with aphasic patients ((Jain et al., 2000); TBI), essentially the GOAT in a multiple choice format, allows for comparison of aphasic and non-aphasic patients using the same standard. It includes 10 items with a 3-choice response format. Using GOAT as the gold standard, the AGOAT (cut-off >90) demonstrated 100% sensitivity and 95% specificity in identifying PTA.
Use by proxy? N/A