julia-pfarr/HarmoniCA_apathy

HarmoniCA — Apathy Model

Part of the HarmoniCA collection for harmonising psychiatric questionnaire items across studies. This model assigns items from apathy questionnaires to one of two theoretically motivated symptom dimensions.

Dimensions

ID	Label	Description
1	Behavioral-Cognitive Apathy	goal-directed cognition and behavior, initiative, planning, curiosity, effort, productivity
2	Affective Apathy	emotional responsivity, emotional blunting, indifference to positive or negative events

Items rated as not belonging to the apathy construct are assigned dimension -1 (Does not fit).

Model Architecture

• Type: ContrastiveModel (contrastive fine-tuning of a sentence transformer)
• Base encoder: BAAI/bge-large-en-v1.5

Training Data

• Training items: 127 expert-labeled questionnaire items
• Questionnaires: AES, AMI, LARS, SAS, MDS-UPDRS (apathy items), NMSSQuest, NPI, DAS, SHAPS, TEPS, SCL-90 apathy subscale, plus data augmentation
• Labels: Expert consensus from a survey of 40 psychiatrists/neurologists (round 1)

Evaluation

Evaluated on 68 held-out items from from unseen questionnaires against expert labels.

Cohen's κ	Accuracy
0.55	0.78

Cross-validation (leave-one-questionnaire-out, 11 folds): mean accuracy 77.9% ± 25.0%.

Limitations

• Trained and validated on Parkinson's disease cohort questionnaires; performance may differ in other populations.
• Dimension structure reflects theoretical consensus among a specific expert panel and may not match all theoretical frameworks.

Citation

in preparation