DECLARATIVE MEMORY COMPENSATION
We have also proposed that declarative memory compensates for procedural memory and other dysfunctions in a wide range of disorders, including DLD, dyslexia, motor-speech disorders (e.g., verbal apraxia, stuttering), autism, Tourette Syndrome, and OCD (Ullman & Pullman, 2015a; Ullman & Pullman, 2015b; Ullman et al., 2020). According to this view (the Declarative Memory Compensation Hypothesis), declarative memory remains largely normal in these and various other disorders, and, because it is very flexible, it can and often does learn a wide range of information and strategies to at least partially overcome numerous types of impairments. In some cases declarative memory may even be enhanced as compared to typically developing children, including in dyslexia (Hedenius et al., 2013), developmental language disorder (Lukacs et al., 2017), and autism (Walenski et al., 2008), thus in turn enhancing its ability to compensate.
For example (See Ullman & Pullman, 2015), declarative memory seems to help people with OCD or Tourette syndrome learn to control compulsions and tics; it allows individuals with autism to compensate for social deficits by memorizing scripts for navigating social situations; and it learns strategies to overcome reading and language difficulties in people with DLD (Lum et al., 2012, Conti-Ramsen et al., 2015), dyslexia (e.g., Hedenius et al., 2013), and autism.
Declarative memory compensation has potentially important clinical implications. First, designing treatments that rely on declarative memory, or that improve learning in this system, could enhance compensation and thus reduce symptoms. For example, drugs known to improve declarative memory could ameliorate symptoms, particularly if paired with behavioral therapies learned in this system.
Second, developing treatments that avoid compensation by declarative memory may increase the likelihood of stimulating and potentially strengthening the dysfunctional circuitry. This is akin to therapies that prevent patients from using their good hand so they are forced to use their bad one, which can improve its functionality.
The compensation also has implications for diagnosis. Many individuals might be compensating their way out of clinical diagnosis (the Compensation Underdiagnosis Hypothesis; Ullman & Pullman, 2015). This should hold especially for individuals or groups with better declarative memory abilities. Indeed, underdiagnosis due to compensation may help explain one of the major conundrums of all these disorders: why they are diagnosed more commonly in boys than girls. On this view, because declarative memory seems to be better, on average, in girls and women than boys and men (see Effects of Sex Differences), females are likely to compensate more successfully than males, even compensating themselves out of diagnosis more often than males (Ullman & Pullman, 2015).
Compensation by declarative memory may also be found in other disorders (Ullman & Pullman, 2015), including ADHD and debilitating adult-onset disorders such as aphasia (Drury & Ullman, 2002) and Parkinson’s disease (Ullman et al., 2002). Indeed, given the power and flexibility of declarative memory, it may play compensatory roles in a wide range of disorders.