Wernicke area

**Location:** Posterior part of the superior temporal gyrus (Brodmann area 22) in the dominant hemisphere (left in ~95% of right-handed and ~70% of left-handed people). It lies near the auditory cortex and the angular/supramarginal gyri (the junction of temporal, parietal, and occipital lobes).

**Function:** Comprehension of written and spoken language. It interprets language and links sounds to meaning. It connects to Broca area (inferior frontal gyrus, BA 44/45; motor speech production) via the arcuate fasciculus, a white matter tract.

**Vascular supply:** Inferior division of the middle cerebral artery (MCA). Embolic stroke is the classic cause.

**Wernicke (receptive, sensory, fluent) aphasia:** - Fluent, well-articulated speech with normal rate and prosody, but it lacks meaning. It contains paraphasic errors, neologisms, and "word salad." - Impaired comprehension of spoken and written language. - Impaired repetition. - Patients are often unaware of their deficit (anosognosia) and may be frustrated or paranoid. - Associated findings: superior homonymous quadrantanopia ("pie in the sky," from Meyer loop involvement) and, typically, no significant motor weakness. This lack of weakness can lead to a missed or psychiatric misdiagnosis.

**Comparison with other aphasias (high-yield):** - **Broca (expressive, nonfluent):** Impaired fluency with intact comprehension and impaired repetition. Patients are aware of their deficit. Right facial and arm weakness may be present (superior division of the MCA). - **Conduction:** Arcuate fasciculus lesion. Fluent speech and intact comprehension, but poor repetition. - **Global:** Both areas involved. Nonfluent, with impaired comprehension and repetition. - **Transcortical sensory:** Like Wernicke but with intact repetition. - **Transcortical motor:** Like Broca but with intact repetition. - **Anomic:** Impaired naming only (often the residual deficit after recovery).

**Mnemonic:** Wernicke's is "Wordy but makes no sense"; Broca's is "Broken speech." Wernicke area is also described as "Where? Understanding."

**Don't confuse with:** Wernicke encephalopathy (thiamine deficiency; confusion, ataxia, ophthalmoplegia, with lesions in the mammillary bodies and medial thalamus), which is a different entity named after the same physician (Carl Wernicke).

**Clinical approach:** Evaluate fluency, comprehension, repetition, and naming. Obtain urgent neuroimaging (CT to exclude hemorrhage, then MRI/CTA). Treat an ischemic stroke with thrombolysis or thrombectomy if the patient is eligible. Speech therapy is part of rehabilitation.