SIR: We are grateful to Drs. Terao and Ikemura for providing us with an opportunity to clarify aspects of our paper.
These authors note that we asked our first patient to bring her musical tunes to mind during SPECT. Although symptom activation paradigms in imaging studies in obsessive-compulsive disorder (OCD) have typically relied on other sorts of manipulations, in our experience it turns out that asking the patient to "obsess" also activates classic cortical-striatal-thalamic-cortical circuits in OCD (Stein et al., unpublished data). More pertinently, despite this admittedly unresolved methodological issue, we would like to emphasize that the patient ordinarily experienced her symptoms as intrusive, consistent with the definition of "obsession."
Drs. Terao and Ikemura also correctly note that our patients experienced tunes as internally generated, but suggest that the term "pseudo- hallucinations" can be applied to such a phenomenon. However, a careful reading indicates unresolved debate around this term, with alternative definitions available.1 Tellingly, it has been argued that the major difference between "hallucination" and "pseudo-hallucination" depends only on the presence of insight.2 In both of our patients the symptoms appeared to be intrusive cognitive phenomena (like obsessions) rather than false sensory perceptions (hallucinations).
Finally, Drs. Terao and Ikemura note that in both of our patients there were no other OCD symptoms. Although it is true that many patients with OCD do have multiple symptoms, there are certainly many other cases in which the primary focus is on a single obsessional concern or compulsive activity.3 This predominance of a single kind of obsessional focus certainly does not rule out the diagnosis of obsessive-compulsive disorder.
In summary, although we continue to hold that the term "musical obsession" is appropriate for our patients, we agree that further nosological efforts are required in this area and that the functional relationship between musical symptoms and temporal lobe abnormalities is consistent with both neuroanatomical and clinical understandings.